Welcome to the 30th lecture in our particle characterization course. In the last lecture, we started discussing nano particles and in particular, there are three aspects of nano particles that we need to be concerned about the synthesis, dispersion and characterization of nano particles. So, in the last lecture, we started to get into some introductory material on what is nano technology, what are the various aspects of nano technology, some applications of nano technology and then we started our discussion of synthesis methods of nano particles and in particular, the bottom up methods. Essentially, nano particle synthesis methods can be classified as bottom up and top down. The bottom up approaches require that we take precursors that are essentially in atomic form and assemble them together to form a nano dimensional material and that is the definition of bottom up. Whereas, in the case of top down, we start with materials that are of micron scale and fragment them down to nano dimensions. So, in terms of bottom up nano particle synthesis methods, we again sub classified them based on the nature of the precursors and we discussed several methods where the precursor is in the form of a solid which must be vaporized to generate the vapor which can then be crystallized to form solid particles. Now, later we also started discussing applications where the precursors are in the form of liquid droplets or vapors. So, we will continue that discussion in this class. There is a method called thermal plasma synthesis which basically requires that you take vapor precursors and introduce them into a thermal plasma. When you do that, the plasma supplies additional energy to break down the precursors completely into atoms. So, the precursors may be in the form of a high molecular weight molecules which using the plasma irradiation can be broken down into their constituent atoms which then can react or condense to form particles and this can be accomplished by providing cooling, the mixing with a cool gas or simply expanding the vapors through a nozzle. This method is used quite widely for the production of silicon carbide and titanium carbide for nano phase hot coatings. Another technique is flame synthesis. Here, the primary difference is that combustion reactions are used to generate the heat that is required. So, particle synthesis here occurs literally within a flame. The flame is used to generate the energy or the heat that is required to drive the reaction to completion. It is a very successful commercial process. In fact, there are millions of tons per year of carbon black and metal oxides being produced using this method. The drawback to this method is that combustion is not an easy process to control. So, it is a complex process but widely used for making oxides and recently we have been able to make various types of oxide nanoparticles as well as sintered agglomerates. In terms of control, it has been found that if you can apply a DC field to the flame that can actually stabilize the combustion reaction and produce a more tightly controlled particle size distribution. Flame spray pyrolysis is a combination of two methods that we have discussed earlier flame pyrolysis and spray pyrolysis. Here, the liquid is sprayed directly into the flame. So, the liquid precursors are injected into the flame. The advantage of this method is that you can use low vapor pressure precursors because the combustion process will supply sufficient heat to vaporize even low vapor pressure precursor materials and this is applied to synthesis of silica particles. Low temperature reactive synthesis is the name given to nanoparticle synthesis methods that do not employ high temperatures. Now, in most of the methods that we talked about earlier energy is being supplied in the form of heat and therefore, there is some limitations to such methods. If you are trying to make materials that are not compatible with high temperatures, then you can actually wind up damaging or changing the composition of the material that you are manufacturing. Here, we try to bring vapor phase precursors to react without adding heat and without producing heat. For example, zinc selenium nanoparticles can be made from dimethyl zinc, trimethylamine and hydrogen selenide using this technique. All we do here is provide intimate mixing. Essentially, we use a counter flow jet reactor that is kept at room temperature, but it provides very intimate mixing of the reactants. The heat of reaction itself is sufficient to allow particles to crystallize. So, it is a very energy efficient process because it can be run at room temperature without external addition of heat and the fact that there is no heat generation also means that it can be essentially done in simple equipment designs where you do not have to worry about heat generation and the heat dissipation and so on. Another method that is been widely used in the bottom up side of manufacturing nanoparticles is sonochemical nanosynthesis. Ultrasound is an interesting technique in the sense that it can be used to synthesize nanoparticles both from the bottom up approach as well as top down approach. Later, we will see how ultrasound can be used to make nanoparticles in a top down kind of application, but when we apply an acoustic field to a liquid, instantaneously extremely high temperatures and pressures can be realized within the liquid as cavitation happens. So, essentially when you apply an oscillating acoustic field, you start forming bubbles in the liquid which collapse and as they do, they release high amounts of energy and according to the hot spot theory, as bubbles implode, temperatures of the order of 5000 to 25000 Kelvin can be realized for a few nanoseconds which is followed by very rapid cooling, but during the time when these high temperatures and high pressures are in effect, chemical reactions can be driven by several orders of magnitude faster than they would proceed otherwise. So, this acoustic cavitation effect can break chemical bonds and can make chemical reactions run very very fast and therefore, it can intensify the process by which nanoparticles are synthesized using chemical reactions. The high cooling rate can be advantageous in some ways because by quenching the reaction which happens naturally in a cavitation field, you prevent crystallization of the product. So, you can essentially make amorphous nanoparticles very easily by using the sonochemical method. Therefore, it is considered a superior process for preparation of amorphous nanoparticles because of this cold quenching mechanism. Insertion of nanomaterials into mesoporous materials also becomes possible because as we have discussed in one of the earlier lectures on surface cleaning, when you couple an acoustic field to a liquid, two things happen cavitation which is a mechanism of bubble implosion and acoustic streaming which is the high velocity unidirectional flow that is induced with very high frequencies when the bubbles are very very fine, but bubble density is very very high. So, the net effect of these bubbles forming and collapsing is that there is no cavitational force that is significant. However, the phenomenon of bubble implosion at very very small size scales leads to this process of acoustic streaming by which the fluid is directed at high velocities in one direction. So, if you can harness this acoustic streaming process, you can take the nanomaterials that you have fabricated and actually make them flow into porosities in materials. So, you can actually insert or incorporate nanomaterials into a porous matrix by taking advantage of acoustic streaming. You can deposit nanoparticles on ceramic surfaces and polymer surfaces and you can form essentially spherical nanoparticles. Sonochemical reactions are particularly suited to making spherical nanoparticles. Indeed, we will see later that when you use sonofragmentation that also has the effect of making spherical nanoparticles. So, there are applications which require sphericity in the nanomaterials and for that, sonochemistry is a good process to use. You can also make very small particles because of this rapid quenching effect. As the particle starts to form, if you can quench the formation process, then you do not provide time for the nanoparticles to grow to larger sizes. So, sonochemistry can be very effectively deployed to control the size. Some examples of materials that are synthesized using sonochemical methods are shown here and other materials are listed here. So, there is a huge variety of materials and compounds that are commercially manufactured using sonochemical nanosynthesis techniques. Now, moving over to the bottom from bottom up to top down methods of nanoparticle synthesis, size reduction is the primary mechanism by which we can make nanoparticles starting from larger sized particulate material. Crushers, grinders, ultrafine grinders, cutting machines, you are familiar with all of these tools from your courses and labs in industrial processing, mechanical operations. They can actually be used quite effectively to do size reduction. However, reaching nano dimensions is very difficult with many of these machines. Crushers, grinders are only good for reducing particle size from say millimeters down to possibly tens or hundreds of microns. A ball mill as well as ultrafine grinders are effective in making particles down to roughly 10 microns. But when you try to get the size below 10 microns to 1 micron or less, there is a huge energy penalty. Some of these size reduction techniques do not work very well and that has somewhat limited their application to synthesis of nanoparticles. A ball mill which I am sure everyone is familiar with is basically a cylindrical shell that slowly turns about a horizontal axis. It is filled to about half the volume with a solid grinding medium and essentially as it rotates, the balls that are in the grinding chamber reach a maximum height and then drop and as they do the impact on the material being size reduced and break it to a smaller size. The advantage of a ball mill is that it can be operated in continuous mode or batch mode. Size reduction happens by a simple impaction process. If you look at the forces acting inside a ball mill, you have centrifugal force which is lifting particles along the sides and gravity force which then causes the ball to drop on the feed and crush it and you can establish a critical speed of the ball mill NC which is related to the acceleration due to gravity, the radius of the shell and the radius of a ball. You want to keep the actual operating speed of the ball mill to no more than 75 to 80 percent of the critical speed otherwise essentially all the balls will become entrained and just keep following the circumferential motion of the grinding chamber rather than dropping on the material to be crushed. So this is a schematic of how the inside of the grinding chamber looks, the yellow popcorn like things or the material that are being crushed and the spherical balls or the grinding media. The ball mill is the workhorse in industry as far as fine grinding is concerned. Applications are limited by high power requirement and low efficiency. I am sure you all recall the lab experiments you have done which demonstrate that as the effective particle size decreases, you have to keep supplying more and more energy to produce new surface area. So it is essentially a self-limiting process as the surface becomes finer, it becomes more and more difficult to reduce its size further. However, it is widely used in many mineral processing industries, cement industry, coal processing and so on. Here are some examples of industrial ball mills. You can see a you know the scale of the equipment. These are huge chambers that are used to make 1000s of tons of material on a weekly basis. So you know it is difficult to think of these machines in the context of nanotechnology where our production rates are much more modest and so many of these industrial ball mills really do not lend themselves to making nanoparticles. However, more recently there have been advances in ball milling technology in particular the high energy ball mill which is an improvement over the conventional ball mill in the sense that it is a much it is a more controlled operating environment. So you can actually control the temperature inside the milling chamber, you can control the pressure, you can even control the chemistry of the ball milling chamber in order to produce product that you need. This is again a schematic of how a high energy ball mill might look. Essentially, the mechanism remains the same, you are still taking material to be size reduced, putting it in a chamber and allowing the grinding media to impact on the material with some force which causes a size reduction to happen. However, in this example you can see that the inside of the chamber is filled with argon and inert material to prevent oxidation. So for example, if you have aluminum or copper that you are trying to produce, if you do this in the ambient environment air itself is sufficient to cause aluminum and copper to oxidize. So if you want to make sure that you synthesize the metal nanoparticle without any oxide being taken up, then you have to provide an inert environment. This table shows the differences between ball milling and high energy ball milling. One of the key differences is in a high energy ball mill, you run the mill for much longer. Essentially, the mean size will keep decreasing as you run the mill longer and longer. So while in a ball mill with a milling time of 1 hour or less, you can achieve particles that are say 10 microns mean size. In a high energy ball mill just by running it much longer, you can achieve much smaller sizes. Also the impact energy is designed to be much higher in a high energy ball mill. The particle size that is produced, well actually if you take a look at it, the output from the high energy ball mill looks not very different from the output from a conventional ball mill. That is because even though you may be size reducing to much smaller sizes, because you are running the process for so long, agglomeration sets in. So the final product that you get from a high energy ball mill is a kind of a powdery substance that has agglomerates or clusters that are micron in size. Now it is possible to take these clusters and then disperse them. So that extra step is required after high energy ball milling to take the material that you have produced and disperse it into the sub micron sized individual particles. In a high energy ball mill structural changes and chemical reactions can be induced. The atmosphere can be vacuum or it can be gas filled in a high energy ball mill and the temperature can be controlled all the way from sub zero temperatures that are achieved using cryogenic fluids to 700 degree centigrade. So the very wide temperature range is possible in a high energy ball mill. The impact energy of a vibrating ball mill can be calculated based on the operating conditions in particular the frequency of the vibrating ball mill. The vibrating ball mill is an alternative to the impact ball mill where the balls drop by the force of gravity and it is another method for making fine particles from coarser feed. However vibrating ball mills are not widely used in industry compared to the impact based ball mills that are more conventionally used. Now why is there a size limit in mechanical grinding? There are really two reasons. One is that as the size decreases particles become monocrystalline in nature and as they do the energy requirement to break the particle keeps increasing. So essentially the particle itself becomes more and more unbreakable as it gets smaller. In addition agglomeration begins to happen. Belting of small particles into clusters begins to happen. And again the longer you run it the stronger are these inter particle cohesive forces and essentially sintering begins to happen after some period of time and these clusters that form over long period of operation can be very very difficult to break down into their component materials. Extended milling also leads to amorphization. This is shown here in a series of graphs that are taken at various time intervals ranging from 23 hours to 73 hours to 165 hours. And you can see that what started out as very crystalline material where the structure can be easily identified soon reaches an amorphous form where it is very difficult to really identify the shape of the individual particles. Essentially you get an amorphous powder which you know if you were to test it using x-ray diffraction would basically tell you that it is a highly non crystalline material. So one of the problems with the extended time high energy ball milling to make nano particles is that it is very difficult to get crystalline materials using this process. There is over time an amorphization that happens which is very difficult to avoid. It is TEM pictures of titanium nitrite nano particles that are produced by high energy ball milling and here you can see the clustering that is happening. This is a good example of characterization of nano particles using tunneling electron microscopy. You can see that the resolution is fantastic. You can actually see particles that are you know nanometers in size and you can actually resolve particles that are nearby which are about a nanometer apart. So the primary advantage of the TEM over scanning electron microscopy is its ability to sensitively detect as well as resolve particles that are in the nano size range and the clustering is very apparent in this picture. Now these are examples of metal oxide nano particles that are produced by milling of various powders titanium, iron, zirconium in an oxygen environment. Again this is done in a high energy ball mill where the interior of the of the mill can be made to be oxygen rich and what you produce is nano titania nano Fe x o y and nano z r o y and here again when you look at the TEM picture at the bottom you can see the extent of clustering that is happening. Clearly nano particles are being produced but by the time you take them out of the mill they have essentially clustered into an agglomerate that is of the order of several hundred nanometers in dimension. So they have to be broken up somehow before you can employ them for further processing. So there is this process that is labeled as Meccano thermal process which involves a two stage procedure. In step one you use high energy ball milling to produce a structure that is a nucleate structure. Step two is to then produce a controlled thermal annealing process which leads to growth. Now thermal annealing is essentially taking a nano material that you have produced and exposing it to high temperatures in a controlled manner in order to obtain a certain structure and size that you are interested in. Typically thermal annealing is done to get a more sintered a harder structure compared to the amorphous structure that a high energy ball mill would normally produce. So if you want to take the output from a high energy ball mill and give it more of a crystalline structure then thermal annealing is a process that is highly recommended. These are examples of nano tubes that are produced by ball milling. Here you can see that ball milling is been able to produce the precursors for nano tubes. So the nucleation structures are there. There are pentagons, microprores as well as nano sized metal particles and you can see that carbon is being incorporated as the source of carbon atoms. Now when you look at this process that combines mechanical milling and thermal annealing it is actually difficult to decide whether you should label it as a top down process or a bottom up process because the mechanical milling itself is a top down process obviously but thermal annealing is where you are essentially taking loose fragments that you have generated by the mechanical milling and bonding them together to produce a crystalline structure. So it is kind of a combination of top down and bottom up methodologies just like the liquid gel technique was that we talked about earlier. So here is some output from this combined process. Boron nitride nano tubes can be produced using this process and you can see the structure of the nano material that results after 10 hours and after 16 hours. In fact high energy ball milling combined with thermal annealing was the first commercial process to be used for the production of boron nitride nano tubes and cost wise actually this is very competitive with bottom up approaches. You can see some prices listed here for grams of material. In comparison if you were trying to make the same materials using a bottom up process it would cost you at least 3 to 4 times as much. There is in literature many applications of ball milling for the synthesis of nano particles and you can see that there is a large variety of materials that are made using the ball milling process particularly popular for making nano tubes. Now these are some results from our laboratory where we have taken carbon and do and try to do size reduction using various techniques. So when we do this in a high energy ball mill and you plot the mean size as a function of time you can see that there is a leveling of effect or an asymptotic effect which in this case is reached at about 6 microns or so and the size reduction stops happening after this limiting size is reached. When you increase the rpm of the ball mill it really does not affect the asymptotic size that is reached what it does affect is the rate at which the size is approached. So by increasing the rpm you can increase the kinetics of the size reduction process but you really cannot do anything about the final size which is more dependent on the dynamics of the mill itself such as the size of the ball the size of the chamber and ultimately the size reduction process itself will stop after a certain minimum size is reached. This is a comparison by size versus energy. So if you look at energy that is being input and the size that is achieved as a result of the energy input you can see that there is a similar amount of energy being consumed at various milling intensities in other words even if you change the rpm as long as the input energy remains the same the final size that is achieved also remains the same and again you can see that the process of size reduction by ball milling essentially becomes energy inefficient after about 5 microns is reached because you can keep increasing the amount of energy that you input without causing any change in the in the mean size after roughly in this case about 50 kilowatt hours per kilogram. Here we compare the ball milling processes with ultrasonication to look at the energy efficiency of these processes. As we have seen in the previous pictures milling at various rpm's starts to show a leveling of tendency around 6 microns whereas if you did the size reduction using sonofragmentation as a technology at in this case at 40 kilo hertz you can keep driving the size much lower than you can with conventional size reduction processes such as ball milling. In fact if you look at this figure more closely you can see that actually milling is a more energy efficient process until a size of roughly 5 microns is reached after which sonication becomes the more energy efficient process. So if you are trying to do nano particle synthesis by size reduction then you are probably better off using a combination of techniques. So to get from an initial size that is let us say around 70 to 100 microns to about 5 microns you should use ball mill to reach that size and after that you start sonicating the particles to do further size reduction. So let us quickly recap what is sonotechnology. We have discussed this in the context of surface cleaning earlier. Sonotechnology refers to intensification of bulk fluid as well as surface and interfacial processes by the combined action of cavitation and acoustic streaming and here we see schematics of what a cavitation bubble looks like just before it implodes. We see a typical acoustic streaming pattern which is essentially uredirectional in nature and at the top we see the typical compression and rarifaction cycles of a sound wave. Here of course the bubbles will be forming during the rarifaction cycle and they will be collapsing during the compression cycle. This is how the cavitation actually happens. There is a bubble growth which leads to a maximum bubble size at which point the bubbles collapse in the compression cycle and releases energy as a shock wave that propagates through the liquid medium and either impacts on particles that are suspended in the liquid or it impacts on a surface that the liquid is adjacent to and the energy that is transferred due to this shock wave impaction causes physical changes or chemical changes to happen and then the cycle keeps repeating itself as new bubbles form and implode. Frequency is a major player in this. As you increase the frequency of the acoustic field the cavitation intensity drops quickly. Actually there is a 1 over f cubed dependence. Cavitation strength decreases with frequency as 1 over the cube of the frequency. So you can see here that as you approach 400 kilohertz, 800 kilohertz or close to 1 megahertz cavitation is virtually absent and it is at its most significant levels for ultrasonic frequencies that are less than 100 microns. The 25 kilohertz to 100 kilohertz range is where you get the most intense cavitation. Some of the advantages of sonofragmentation for synthesizing nano particles are high purity because essentially you are taking the base material. If you are trying to make nano alumina, you are taking micron sized alumina. So there is no additional chemicals involved and all you use is high purity water typically. So you immerse the micron sized particles in high purity water, turn on the acoustic field and you start fragmenting the particles. So it is a very simple process, energy efficient, easy to scale up and also it does some interesting things to the crystalline structure of the material. The sonication introduces what is known as lattice strain. So the crystallinity of the particle is maintained. It does not become amorphous with extended exposure like high energy ball milling does, but there are subtle changes in the crystallinity. Effectively from a physical view point, what you see is a rounding off of the corners so that a material or a particle that is subjected to long term sonication becomes increasingly spherical with the passage of time. It also lowers the sintering temperature. Now that is an advantage when you are using these particles in an application that requires them to be sintered and the ability to use a lower temperature is advantageous from an energy efficiency view point. Of course the reason that the sintering temperatures are lower is because the process of sonication increases the surface energy of the particle. So the natural adhesiveness or cohesiveness of the particle is greatly increased by the process of sonication. This is actually true for all top down methods, but in particular ultrasound because it imparts such high energy to the particles to fragment them, leaves behind a residue of the energy which is much higher compared to for example high energy ball milling. So the particles, nano particles that are synthesized using sonofragmentation are essentially much more reactive, much more adhesive and much more conformable to your process compared to nano materials that are made by other techniques. Here are some examples of particles that are produced using sonofragmentation and again from a particle characterization view point what you see here are data that are produced using a particle size analyzer. In this chart you can see that compared to the untreated alumina particles as you expose them to sonication for various periods of time and this is using fairly low power ultrasound 88 watts you can see that the mean size keeps shifting to a smaller size range. This is an illustration of a silica particle or silica powder that has been exposed to ultrasound and you can see here that a very characteristic bimodal distribution develops over time and here again what you see is a reduction in the mean size of particles and also an increase in the volume fraction of particles in the finer size range. So you can see that there is a significant enrichment of particles in the sub 1 micron size range as you subject the powder to sonication over an extended period of time. This is a sample of zirconia powder that has been subjected to ultrasound and again you show you see the same trend the volume fraction of particles in the larger size range decreases with increasing sonication time and the volume fraction of particles in the sub micron size range increase with increase in sonication time. So the mean size decreases as well. So if you actually took all the data that was in literature and plotted it as mean particle diameter versus sonication power in watts, you see a very interesting trend that with increasing sonication power you can drive the mean particle diameter after 30 minutes of sonication down to 1 micron. However if you look at the literature data there is not much work reported for particles that are smaller than 1 micron. It is reasonable to expect that this line cannot simply be extrapolated to sub micron sizes. There will be a leveling of effect even with sonofragmentation. However based on this it is reasonable to expect that sonication will remain a viable technology even for particles that are smaller than a micron. If you look at the fragmentation rate expression reported in literature the fragmentation rate in sonofragmentation is related to the ultrasonic power input with a exponent of 0.38, particle volume with an exponent of one third and total suspension volume which is in the denominator. This is an interesting expression what it implies is that as the total suspension volume increases the fragmentation rate will decrease reciprocally. The reason for that is that sonofragmentation is a volumetric effect. You are supplying a constant power if you increase the volume of the liquid then the power per unit volume decreases and that results in reduced fragmentation. It is reasonable to expect that power input will be in the numerator but an interesting finding is that particle volume is in the numerator. What that implies is as the concentration of particles in the suspension increases sonofragmentation efficiency will increase. That is somewhat counter intuitive because what that says is that if you process more material the process will be more efficient. That is usually the reverse of what happens with most chemical processes as you try to pump in more material your efficiency will decrease. The fact that in this particular case the particle volume or concentration is in the numerator gives us a lot of hope that scale up would not be that difficult because in scaling up what you are trying to do is essentially process more material. At least this expression would indicate that fragmentation rate will not decrease when you do that if anything it will increase as the particle volume to the power one third. Now, if you look at the mechanism of sonofragmentation there are actually two mechanisms by which particle fragmentation happens. There is direct interaction of the bubble with the particle and also interaction between two adjacent particles that are being accelerated by the bubble explosion. So, in this particular case the bubble collapse due to implosion is one of the mechanisms but the other mechanism is simple particle to particle impact. So, particle fragmentation here occurs due to the violent bubble collapse as well as inter particle collisions and the resulting attrition in the particles. So, this is basically what happens the bubbles impact on the particle particles impact on each other and the net result is a fragmented population of particles. So, in a laboratory setting this can be easily simulated by taking a beaker with distilled water put some micron sized feed particles into it and subjected to ultrasound which can be in the form of a tank with bottom mounted transducers or it can be in the form of a horn or nozzle through which the ultrasonic energy is transmitted. And if you look at what happens in the beaker now you will see that you have essentially three layers that show up. The bottom most layer will contain the unfragmented particles mostly the feed particles that have escaped the process of sonofragmentation. The top most layer will show the fragmented particles that have been reduced from micron sized to nano sized because of the sonofragmentation mechanism. Then there will be a middle layer which is a mix of both it will have a fraction of the particles being the size reduced nano dimensional particles and it will have a fraction of the particles being the original micron sized particles. So, this gives us a clue that if you were to combine this sono process with a kind of beaker decantation process you can not only make nano particles but you can also quickly collect them by a process that is based upon the sedimentation characteristics of the various sized fragments. If you have a beaker decantation type of setup you can simply take the top layer off and drain it into a collector and that will be enriched in nano particles whereas the bottom most layer can be recycled so that it can be size reduced further. What you can also do is take this sample which is stratified you know with three different size distributions and you can actually mix them up again. Now, that may be important in some applications where you need a range of particle sizes rather than a particle size in a particular size range. So, it is very easy to take this stratified layer of sub micron, micron and nano sized particles and remix them to produce a homogeneous suspension. So, in this particular case it is possible to take particles that have been produced by sono blending as this is called and essentially make a uniform composition of nano sized, sub micron sized and micron sized particles which can then be used to make composites. One of the major applications of sono technology is not only to synthesize nano particles but also to incorporate them into polymers and other materials to make composite materials. So, the way that works is you take this blend of various sized particles dry them out and keep the blended sample ready to make into composites. The polymer precursor itself has to be prepared by dissolving it in a solvent and then you take the nano materials that you have prepared by your nano your sono fragmentation process and blend them into the polymer that you have prepared by dissolving in a solvent and then you can again use sonication to uniformly mix the particles into the polymer and the polymer matrix that you have prepared in this fashion will essentially look like this. You will have the polymer material within which the nano particles are incorporated. Now, there are two important things here. The particles should be non-agglomerated. So, they should be dispersed very well. They should also be distributed. We will see later on when we talk about nano particle dispersion that these are two different characteristics dispersion and distribution. They are both very important in preparing a high quality polymer composite material. The strength of these nano composites can also be tested by subjecting them to cavitation erosion. For example, you can take this composite material that you have prepared and expose it to an ultrasonic field and look for weight loss and as the material becomes stronger, there will be less weight loss due to cavitation erosion. So, ultrasonic processing can be used very effectively to synthesize nano particles, to prepare nano composites and also to test the cavitation resistance or strength of the nano composites. In our laboratory, we have some state of the ultrasonic facilities that we use to make nano particles as well as the nano composites. You can see our 20 kilohertz probe type sonicator here on the left hand side and the 58 kilohertz tank type sonicator on the right hand side. On the right hand side picture, if you look down on the water, you can see that the ultrasonic field is very uniform over the entire surface. That is in fact, the primary advantage of the tank type sonofragmentation process that you produce very uniform cavitation patterns over the entire liquid, whereas in the probe type sonicator, the acoustic field is highly localized. So, you get very high intensities in the immediate vicinity of the probe, but as you move farther away from the probe, the energy intensity drops off very rapidly. Some of the analyzers that are used for testing particle compositions and sizes and counts are shown here. The left hand side top picture shows a turbidimeter. You may recall that we discussed this in the context of measuring particle concentrations in suspensions. Turbidities are measure of the total scattering intensity of particles in suspension. So, it can be used as a qualitative measure of particle size as well as particle concentration in liquids. The top picture on the right hand side shows a laser particle counter, which works by the principle of laser scattering, which we also discussed in one of the earlier lectures. This particular laser particle counter can count particles in liquids down to 1 micron. And at the bottom, you have a particle size analyzer, which works by the principle of acoustic attenuation spectroscopy, which we also discussed earlier in one of the lectures. So, these are the three instruments that are very widely used in our laboratory as well as many other laboratories to characterize particle sizes and particle counts in liquid suspensions. The data that we will be reviewing here are taken from one or the other of these instruments. So, here we see what happens to feed particles of alumina that are subjected to sonofragmentation. So, the feed size that is shown on the left hand side graph is 74 to 80 microns. When you expose it to 20 kilohertz ultrasonics at 500 watts for 30 minutes, you can see that there is a substantial reduction in size and the particle mean size is now close to 1 micron and you can see that a substantial fraction of the particles are less than a micron. So, even a fairly short duration sonication is sufficient to make a sizable number of submicron particles. Another indicator of size reduction is the color change. You will find that for the same material in this case white fused alumina, which is being size reduced, the color of the suspension changes as particle size decreases, which actually gives us an idea that if you can monitor the turbidity or the color of the suspension quantitatively, that can actually be used to track size reduction without having to use more sophisticated techniques such as a particle size analyzer. So, the graph shows sonication time in minutes and on the left hand side vertical axis, we see the particle size that results after sonofragmentation and you can see that that decreases to a very low value. On the right hand side vertical axis, the data are plotted in terms of turbidity, which is a measure of particle suspension in the liquid and also the color of the suspension and you can see that with sonication time the color essentially becomes darker and darker, which is indication that we have many more particles now in suspension but of smaller sizes. So, this is an interesting plot that says that color change can actually be correlated to size reduction when you subject a suspension to sonication in order to achieve size reduction. Here we are showing the effect of feed particle concentration on size reduction. The interesting thing here is that it is actually not a monotonic relationship. The fragmentation rate expression that I showed earlier seemed to suggest that as particle concentration increased, the size reduction efficiency will keep increasing. However, you will see from this figure that that is not necessarily the case. There is actually an optimum value of particle concentration at which you have the best size reduction efficiency but if the concentration increases beyond that the size reduction efficiency actually starts to drop and the reasons for that are interesting and we will pick up the discussion from this point in the next lecture and we will highlight the influence of feed particle concentration on size reduction efficiency. Are there any questions on what we have talked about today? So, see you at the next lecture.


Dyma'r cyfnod o'r cyfnod i chi'n amser. Fy enw'r amser i'n ddweud i chi'n gael i chi'n gweithio'r ystafell ar y OU History Lecture Series, a mae'n ysgrifennu newid yng Nghymru ar y OU History Department i'ch gael i'r gweithio ar y cwmdeithasol yr oedlaethau cymdeithasol yng Nghymru ar y gael i chi'n gweithio ar y oedlaethau. Ond mae'n gweithio'n gweithio ar y oedlaethau i chi'n gweithio'r ysgrifennu ar gyfer cyfnod. Ac mae'n mynd i wneud o'r hollwch gwybod yw'n ysgrifftau yma ar y gyfer hynny. Mae'n gwybod i'r cyfnod yn dysun o gyntaf, ac mae'n bwysig i'r ysgrifftau i wneud, ac mae'n gyfnod i'n meddwl i'r dyflawn oedd yn gweithio'r gwybod. Yn gweithio'r Llewc yn gwybod, ac o'r ffordd yw mae'n gweithio'r adroddau i ddiweddio'r hwnnw, felly mae'n cymaint gweithio yw'r adroddau. The procedure, if you are watching live and you like to send a question in, is to send it to the email address which is next to the to the kind of the video window, but I'll give it to you again, just in case, it's FAS FAS sorry F-A-S-S rogue dash lectures at open.ac.uk. Please feel free to send your questions in if you are watching online. If you're in the room, the procedure is to put your hand up. I hope that's not too technical for everybody. So with no more ado, it's my very great pleasure to introduce my friend and colleague, Luke Andre Brunet, who is a history lecturer in the history of 20th century Europe, and Luke is going to be talking to us today. With Europe, but not of it, why Britain joined the European community. Over to you, Luke. Great. Thanks very much, Richard, for the introduction. And hello and thank you to all of you who are joining us today in Milton Keynes and to those of you who are joining us online. So I'm delighted to be giving the first lecture in this series, which is organised by Richard, and part of the events to mark the 50th anniversary of the Open University. And as Richard mentioned, I think the subject of tonight's lecture could hardly be more topical, as you know, this evening, just after this lecture, I think, the House of Commons, the MPs will be voting on the proposed deal of Theresa May on the terms of Brexit. Now, given that the future relationship of Britain with Europe could well change quite significantly by the end of the evening, I think I'll refrain from commenting too specifically on the Brexit deal currently being debated in Westminster and any musings on the imminent future of Britain's relations with the European Union. So instead, this evening, I'd like to focus on Britain's initial relationship with the forerunner to the European Union, namely the European community and before that the European coal and steel community. And I'm interested especially in exploring a specific puzzle around Britain and Europe. So when the European community was first set up in the 1950s, Britain was invited to join as a founding member, but the British government decided against it. So the European community was set up in 1958, but within barely three years, by 1961, the British government had come to the opposite conclusion that it should belatedly seek membership in the European community. So this was a dramatic U-turn in British policy and one whose consequences we're still grappling with today. So in today's lecture I'd like to delve into this and I'd like to look at two related questions in particular. So first, why did Britain decide to not join the European community in the 1950s? And then second, why did the British government reverse this decision by 1961 and apply to join so soon after the community was set up? Now before we dig into these two questions, I think it would be useful to contextualise this discussion just with a very quick overview of the history of European integration since the end of the Second World War. So for that we go back to May 1950 when the French government proposed the so-called Schumann Plan. As this was written by Jean Monat, we see in the photograph who was the head of French economic planning at the time, and it was put forward by the French Foreign Minister, Robert Schumann. And the idea, effectively, was to pool the coal and steel industries of several countries of Western Europe, really whoever was willing to sign up, and that these industries would be placed under the authority of a supranational body known as the high authority of the coal and steel community. And by supranational I mean that specific agreed upon powers would be delegated by national governments to this European high authority whose decisions in these areas would be binding. And this led in 1952 to the creation of the European coal and steel community. Later on in the 50s this was expanded to other areas of the economy, and in 1958 we saw the creation of the European community or the European economic community as the full name. Now in both cases six countries agreed to participate. France, West Germany, Italy, Belgium, the Netherlands and Luxembourg were collectively usually referred to as the six for obvious reasons. Though in Britain the favored term tended to be the somewhat derogatory little Europe to refer to this grouping of six countries. Now in 1961 the British government led by Macmillan belatedly applied to join the community. Now unfortunately for Britain the road to membership was a bumpy one as we can see from this German cartoon from the period. Now in 1963 the French president Charles de Gaulle, pictured here with Macmillan vetoed the first British application to join. Four years later Harold Wilson and his Labour government applied to join yet again and once more the French stalled that application. In 1970 the Conservative government led by Heath applied yet again or reactivated that 67 application which finally was successful and Britain joined the European community in January 1973 along with the Republic of Ireland and Denmark. Finally 20 years after this in 1993 the European community became the European Union of which Britain is for the moment still a member. So this gives us a potted history of the process of European integration over the past few decades and this is hopefully should serve to contextualise our discussion and specifically it allows us to tackle the question so why did the British government choose to not participate in the Coal and Steel community and then the European community? Well the traditional explanation in much of the historiography is that this was a catastrophic choice by the government led by Clement Attlee. So it's argued that Britain overestimated its strength following its victory in the Second World War and believed that Britain remained one of the big three alongside the United States and the Soviet Union. The British government is also criticised for effectively favouring its empire even as it crumbled around them in the years after the Second World War over cooperation with their closest European neighbours who were in the midst of an economic boom at the time. So to use a phrase coined by the Conservative politician Anthony Nutting Britain missed the bus by not joining in the 1950s. Now there's certainly some merit to this explanation and in hindsight the British decision not to join the European community at its creation meant that Britain missed the opportunity to decisively shape Europe's first institutions during this time and the UK had it joined in the 1950s might well have emerged as the leader of this block of six or seven or potentially even more European powers which Britain might have been able to use to further bolster its position as a great power on the world stage. But rather than retrospectively dismiss this decision as a missed opportunity I think it's more interesting to go back and try and understand why the British government at this time made this decision based on the information available to it at the time. I think we can focus on three main factors to understand that decision. So one factor of course was the importance of the Commonwealth. Now in hindsight it's clear that Britain backed the wrong horse in favouring trade with the Commonwealth over trade with the European community but in the early 1950s this was by no means clear. First of all the economies of the other European powers were not particularly impressive in the early 1950s. They were still recovering from the Second World War where unlike Britain the six had all experienced the ravages of military defeat and occupation and far more of their infrastructure and their industrial base had to be rebuilt than was the case in Britain even with the damage sustained from the Luftwaffe over the Second World War in Britain. Now it's also important to remember that the economic boom in Western Europe associated with this period came later on in the 1950s indeed partially as a consequence of the process of European integration. So in 1950 when Britain received the invitation to take part in the Schuman Plan Britain's industrial output was roughly equivalent to that of France and West Germany combined. In terms of trade meanwhile the importance of the Commonwealth still significantly outweid Britain's trade with its continental partners. So in the early 1950s the Commonwealth accounted for just under half of both Britain's exports and imports. The corresponding figure for the six during this period is about 12 and 19 percent so significant figures but markedly less important than trade with the Commonwealth. So based on the existing economic situation in the 1950s it made more sense to the British government to maintain and protect its existing trade with the Commonwealth than sacrifice this in favour of the highly uncertain gains that joining the community might bring. Now the second consideration had to do with the supranational architecture of the community and the pooling of sovereignty which was made a precondition of joining the community. Now in the Brexit referendum campaign of 2016 of course this pooling of sovereignty came under attack as the leaf side called on the British electorate to take back control. Now these days we typically think of this argument as one on the political right maybe associated with figures from Nigel Therodge to Boris Johnson to Michael Gove and so on but in the early 1950s it was a decidedly left wing argument that focused on opposition to sharing control of British industry. So at the head of Labour's first majority governments elected in 1945 and then again in February 1950 Clement Attlee had succeeded in the long held Labour objective of nationalising key industries. In 1946 we see the nationalisation of coal mining followed in 1949 by the Iron and Steel Act. From the perspective of the Labour government the invitation in 1950 to share control over these industries which had only just come into public hands in Britain led to concerns that membership of the community would compromise Labour's economic priorities. Indeed this left wing argument that the European community and later on the European Union is effectively a capitalist club that would thwart democratic socialism at the national level is a concern that we see raised intermittently from the left ever since. Now the third factor informing the British government's decision to not join had to do with Britain's role as a world power. So unlike the six of course Britain had not suffered military defeat and occupation and regime change during the Second World War it had been one of the victorious powers and it had influenced the shape of the post-war international order. By the early 1950s of course it was clear to the British government that they were not a superpower in the same category as the United States and the Soviet Union but it nevertheless remained an important international power. It was an ally of the United States through its empire it had an important string of strategic naval bases throughout the world and from 1952 onwards Britain became the third nuclear weapon state joining the two superpowers and following the London Conference, the Commonwealth Conference of 1949 it seemed that the Commonwealth now including the Republic of India had a bright future ahead of it. So all of this dissuaded the British government from pooling its sovereignty and its industry with its Western European neighbours and it's also important to remember that this idea of Britain with its Commonwealth and Empire as being separate from the rest of Europe was certainly not a uniquely British view. Jean Monnet, for example, the brains behind the European Coen Steel community and the Schumann Plan had suggested in the 1940s that alongside the United States and the Soviet Union that a united Europe could stand as an important international player on the world scene but alongside these three he identified a fourth player, namely Britain with its Commonwealth and Empire which Monnet acknowledged was distinct from a united Europe founded mainly on a Franco-German axis. De Gaulle's veto of Britain's application in 1963 was also justified at least partially on the grounds that in his view Britain was not fully European. So to sum up, while the British decision to not join the European community meant that the UK missed its chance to shape the first European institutions in a way that may have been more to Britain's liking this decision was not simply the result of delusions of grandeur in the aftermath of the Second World War rather based on the situation as it appeared to decision makers in Britain in the early 1950s it was a perfectly rational policy on its own terms and the government concluded that the national interest would be best served by not joining the community. The problem, however, is that the conditions that informed this decision deteriorated rapidly in the years following. So while Commonwealth trade had been far more important for the British economy than trade with the rest of the Europe in the early 1950s this was no longer the case by the early 1960s. So 1950 for example the year of the Schuman Declaration the Commonwealth took roughly half of Britain's exports. By 1960 just ten years later this figure had fallen to 30%. Moreover the members of the European community were enjoying a sustained economic boom outpacing Britain in economic growth year after year and as a result by the early 1960s Britain was now doing more trade with the six members of the European community than it was with its Commonwealth. So if rational policy making dictated that Britain should ensure the greatest possible access to its main markets then this meant saying no to Europe in the 1950s but from the 1960s onwards yes to Europe. Now even more important than these changing economic realities I would argue is Britain's rapidly diminishing presence on the world stage. In 1956 of course we have the Suez crisis in which Britain was forced into a humiliating reversal of policy as a result of the threat of US economic pressure leading to the resignation of the Prime Minister Anthony Eden. The late 1950s also saw the acceleration of decolonisation in Africa and this along with the exit of South Africa from the Commonwealth in 1961 under its apartheid regime highlighted the fact that the Commonwealth had become a much more diverse organisation than it had been and one much less susceptible to bending to Britain's will than had been the case earlier when it was a small group of the so-called old dominions or white dominions. Furthermore the influence of the US on Britain's decision was crucial. The success of American administrations had supported and encouraged the European integration process led by France from the early 1950s onwards and were consistently supportive of Britain applying to join the European community. It was also feared that with Britain's relative political or strategic decline during this period and with Britain being outpaced economically by the members of the European community that the United States might come to favour another European power, specifically West Germany as its preferred European partner rather than Britain. So in this sense joining the community far from being at the expense of Britain's so-called special relationship with the United States would actually be a means of strengthening it and making Britain an even more valuable partner to the United States. So in short against the realities of Britain's economic weaknesses and ongoing decline as a great power the European community was seen as a means for Britain to bolster its power internationally. Seriously despite Britain's weakening position the Macmillan government never really doubted that Britain would be able to set the terms on which it would join the European community. So as a result the UK's first application to join in 1961 came with a long list of special arrangements and exemptions ranging from protection of British farmers to commonwealth links to relations with other trading partners and so on what we might describe today as wanting to have one's cake and eat it. The rejection of this application in 1963 was perhaps predictable and only when Britain reapplied largely on the community's terms rather than trying to set the terms itself was Britain ultimately successful. Now this discussion of Britain's reasons for applying to join I think brings out two key insights. So first Britain's motivations were largely defensive. The government wanted to curb Britain's economic and political or strategic decline and saw membership in the European community as a means of doing this so there was very little enthusiasm within the government for the European project as such. Rather it was simply seen as less bad than the alternative of being shot out of the community altogether. We can see this in the political cartoon published in August 1961 just after the Macmillan government applies and we see Macmillan very hesitantly dipping his toe in the water without much enthusiasm. Second, there never seemed to be any doubt in the minds of the members of the British government that once Britain was part of the community that it would emerge naturally as the bloc's leader. Indeed the political argument behind Britain joining was largely that the community could take the place of the Commonwealth and so Britain's role rather than being ahead of the Commonwealth would be the leader of this Western European bloc. It was never seriously entertained that this might not happen for example that the French or German governments may not be so eager to be placed under British tutelage. So by means of a conclusion then I'd like to return to the puzzle that I set out at the beginning of this evening's lecture. Why did Britain not join in the 1950s and then apply to join in the early 1960s? Well despite the apparent inconsistency in British policy I would argue that there was in fact an underlying consistency in the British government's pursuit of what it thought would be best for Britain. Specifically throughout this period the government followed the policy of maintaining or securing the greatest possible access to Britain's main trading partners. Although in hindsight it's clear that Britain backed the wrong horse in opting for the Commonwealth over the community in the 1950s it was nonetheless a rational policy in the pursuit of the national interest. So too was the decision to apply to join in 1961 even if that application was handled rather poorly. So I think this marks an important contrast with today where Brexit effectively means adding barriers to trade with Britain's most important trading partners. Similarly the decision to join was informed by Britain's declining international position and the diminishing role of the Commonwealth in the hopes that the booming European community could be the means of shoring up Britain's standing in the world. We can see this depicted in yet another cartoon where the Commonwealth is presented as a sinking ship but Europe as a rather promising alternative but today however it's not at all clear to possibly take the EU's place. And I think the most likely result is a decline in Britain's international position and influence in the world. But this is in part explained by a crucial difference between the decision to join and the decision to leave. Now the decisions regarding British membership in the community that we've been discussing this evening in the 1950s and the 1960s tended to be taken by a small group of ministers and policymakers unlike the choice to leave in 2016 which of course was decided by a national referendum. So the outcome of the referendum suggests in part that voters are more concerned with questions of immigration or such as the funding of the NHS rather than the rather more obscure questions of trade flows and Britain's international prestige. In other words arriving at a cabinet decision and winning a national referendum require two decidedly different strategies. Throughout the 1960s and in many ways ever since British governments concluded often reluctantly and half-heartedly that it would be less bad for Britain to be a member of the European community or later the European Union than to be outside. And we can see this attitude reflected in a slogan from the remain side in the 2016 referendum, better off in. This reflected the sober but somewhat unenthusiastic assessment that things would be worse for Britain if it were to leave. And this ultimately proved to be less appealing to the optimism reflected in the message of take back control. Now at this very moment in the House of Commons of course MPs are struggling to define precisely what taking back control actually means. Whatever the outcome it's clear that the consequences of Britain's decision to apply to join the European community back in 1961 continue to shape British politics today. Thank you. OK thank you Luke for a fascinating talk which provides some really useful historical context I think ahead of tonight's votes in Parliament. So it's just a reminder to people at home if you have any questions you can email them. Richard will be manning the email and looking out for questions from people at home. In the meantime though I'll be taking some questions from people in the room so do we have any questions to kick things off? Yes. OK a couple of points. When the ECSC was set up the whole idea of that was to combine the steel industries of France and Germany because it's very difficult to go to war if you didn't control your own steel industry. But obviously Britain must have rejected that idea for whatever reason. The second point I can't think can you answer that bit as the first point? Sure. Great. You're absolutely right. In the Schumann Declaration Robert Schumann highlighted the symbolic nature of Colin Steele saying that these were the necessary industries to wage war and that by pooling them it would make war not only unthinkable but materially impossible. So I think at the heart of it the Schumann plan was effectively a French proposal focused squarely on western Germany and there were all sorts of other reasons behind France's strategy for dealing with Germany at that time to explain why that was the case. But it was also open to all countries in western Europe. Italy joined largely for other reasons for both west Germany and Italy. Part of the appeal was that of course they had been the Axis powers in the Second World War they remained to differing degrees international pariahs on the world stage whereas by joining they were able to be rehabilitated effectively and stand as equals to France. For a country like the Netherlands for example they didn't really have much of either a Steele or a coal industry but they found that it would be politically advantageous to join. So I think you're right that it was founded primarily on this question of ensuring Franco-German peace in the post-war era but it was certainly open to Britain and it might well have joined as the other four countries chose to. The second point if you don't mind as a young teenager I can remember going round the streets with posters of Edward Heath etc extolling the virtues of the EEC as it was then and if you looked into it you knew that the whole point of the EEC was in the end a United States of Europe which I thoroughly agree with. You've never heard this extolled during the debates and you certainly hear very little about that now because personally I don't think the British people have ever been truly European. Right, so I think that you've touched on a really important debate not only within Britain but across every member state of the European Union today which is just how federalist should the European project be is the ultimate aim to create more or less a single political entity, the United States of Europe or is it rather much more effective cooperation, economic efficiency and so on. And I think even amongst historians is an important debate of well was the European colon steel community really primarily motivated by this idea of the first kind of the founding step of what would ultimately become the United States of Europe or was it purely about national self-interest of the countries that joined. But I think you're right that in Britain that I think the federalist voice is much quieter or finds much less resonance than certainly in France or Germany although even today that's problematic in those political environments as well. I think we have a question from someone at home watching online. Okay, Stuart is asking whether Luke would like to say anything about the impact of EFTA on the 1961 decision to apply for membership. Would you like to say something about that, Luke? I would. Thank you, Stuart. And Richard for that question. Yes, so one thing I should say was in a draft version of this talk which ended up being an hour long. So the 20 minute version EFTA got cut out unfortunately. But yes, so in the mid 1950s after the European community was set up, Britain tried to create its own free trade bloc, the European free trade area or EFTA with the members of Scandinavia, Switzerland and slightly controversially, the sort of fascist regime in Portugal. And this was meant really as an alternative to the European community. But in the end it didn't really succeed for a number of reasons. But it was never envisioned as anything more than simply a free trade area unlike the European community which had this super national element which set it apart. And so I'd mentioned that the UK had wanted a number of exemptions when it applied to join the European community in 1961. Among these was that it wanted to keep all of its privileged economic relations with its partners in EFTA and the European community effectively said no. But by the early 1960s even Britain had abandoned hopes that EFTA would amount to a real alternative to the European community. So I think it shows that Britain was engaged with its European neighbours if not necessarily with the sixth, with the seventh as the EFTA was known. But ultimately that Britain was unsuccessful in mounting a challenge to the European community. Do we have any more questions in the audience? Can I first of all thank you very much for a really interesting talk. I certainly would have been happy to listen to the hour long version. I think you did really well to condense that into 20 really interesting minutes and I just wish that both the people at Westminster and indeed everybody who turned up for the referendum knew a little bit about this background and so striking particularly a lot of the parallels you talked about having your cake and eating it and the idea that the Macmillan Government went into these negotiations thinking we can really make demands, we're so impressive and clearly the same things happening now and it's not really necessarily the case so I think it's really food for thought but I wondered whether at the time that these negotiations were made rather than the negotiations which follow the decision that's being made yes we will go in whether anyone gave any thought to how one would possibly in future get out as is clearly where we are now. Did anyone think ahead? What if it doesn't work out? What if actually eventually there will be other trading partners even more promising which is of course one of the arguments we're hearing did anyone think ahead? It's a very good question I'm inclined to say that it wasn't really top of mind I think the idea was well how do we protect as much as of what we already have in terms of things with the Commonwealth and so on and have all of those advantages and the advantages of community membership and then I think the idea was that if Britain couldn't get a good enough deal that it could simply walk away and rely on the Commonwealth to my knowledge there wasn't any escape hatch built in to that strategy but when Britain finally does join of course in 1973 the first thing that they do rather than try to emerge as the leader of the bloc or fit in as good Europeans is that they immediately try to renegotiate all the things that they just agreed to to get in they try and reopen them from the inside and so this is the renegotiated package which is then put to the British people in the 1975 referendum asking them do you want to remain part of the European community or not which of course had a very different outcome from the 2016 referendum And one more question over here I was just curious to know in terms of what people expected at the time we joined how far did they expect the European community to have control over not just our trade but other aspects of life our legislation and immigration what was the expectation in terms of how far we would give up control to Europe So that's a good question I think so initially I think there wasn't much in the way of fears of this building over into other areas because it was a gradual process and I think the idea was that Britain as a member would be able to put a break on certain sort of the more federalist tendencies with which the British government might be less comfortable and we see this particularly during the Thatcher period and the negotiation of the single market and so on and actually as touching on migration initially the British fears were that with the greater freedom of movement of people that the issue wouldn't be migration into the UK it would actually be migration out as all these Britons that fled Britain with its economic problems and instead stampeded to the dynamic economies of France and Germany and so on and certainly in the 1975 referendum for example migration didn't feature at all food prices did but migration was virtually absent I think we've got one more question from someone at home do you Richard? Thanks Neil Okay so Malcolm is asking and this is a tough one for you Luke so Gerdjialoins are there statistics regarding the demographics demographic comparison between the 1975 referendum to join and the 2016 referendum to leave no pressure By demographic I mean almost certainly somebody has crunched these numbers but it just I don't know if I can ask a follow up question to clarify but by means of who backed sort of remain and leave in the the pro Europe and anti Europe I'm not entirely sure about the demographics of the sort of age groups and so on but certainly the support for Europe was much broader in 1975 and even amongst the political classes and we have a figure like Harold Wilson who of course was Prime Minister in 75 in the early 1960s he was opposed to community membership by the mid 1960s he'd come around to the idea that yes Britain is better off in than out and of course applied in 1967 of the second application to join and in the 1975 referendum he was able to remain somewhat neutral he tended to prefer or he believed that Britain would be better off in Europe than out of Europe but he didn't take on a lead role in the campaign that was left to other cabinet colleagues notably Roy Jenkins but really on among the leading political figures who actually campaigned against British membership in the 1975 referendum they tended to be not fringe politicians but the people on the extreme right or left tended to be the most prominent supporters so people like Enoch Powell on the right, someone like Tony Ben on the left who were on the right and left wings of their respective party, Powell of course by this time had been ejected from the Conservative party I think the only newspaper backing the anti-European side in the 1975 campaign was the Morning Star on the grounds that it didn't really suit the communist agenda to have a strong European community whereas the Daily Mail, the Telegraph and so on were all fully in favour of Europe and obviously things changed a bit since then so I'm not sure Malcolm that answers your question OK time for another question from the audience Ian's got one here I was intrigued by the fact that when you were discussing economic matters the trade changes and so on your juxtaposition was always between the European community and the Commonwealth but of course there's another player which is the United States which isn't just a strategic military whatever connection for Britain it's also been a very important trading partner and I think I'm right in saying off the top of my head that even now remains the largest by individual country remains the largest single trading relationship with Britain and certainly in terms of investment relationships I think is significantly the largest so I wonder if it's quite as clear cut as you were making out that in the 1950s it was self evidently the national interest that the Commonwealth was the way to go and by the 1960s things have flipped in the sense that there's always been this additional thread about Britain's relationship with the United States which happens on a multi level including the economic that's an excellent point and something that I would have happily gotten into in the lectures I'm glad we're able to address it here so of course the US is a crucial partner economically but also militarily politically and so on of the UK throughout this time and I think the US matters especially for a couple of reasons first of all Britain wants to maintain its economic relations with the US though that doesn't particularly affected by its relations with the European community I think Britain sees the community not as a kind of closed autarkic grouping to join but they want to ensure that they can continue trading with the United States and also it's important to note that the United States in this period is partially responsible for the declining trade relations between Britain and the Commonwealth because the US in the post-war period is eating into traditionally British zones throughout the Commonwealth so it isn't simply a matter of dynamic European economies and a declining Commonwealth the US certainly has a hand in the latter tendency and of course as I mentioned in the lecture I think the US was quite supportive of Britain joining the European community because they expected that it would contribute to prosperity across the North Atlantic which is very much in the US interests so they certainly did play a role and it is a little bit more complicated than in my simplified version of the lecture and another question from someone at home Margaret in London is asking would it have been consistent with the aptly government's policy to nationalise Colin Steele to then have ceded that area of policy to a supranational authority? That's an excellent question I think that was one that was debated within the aptly government itself and the aptly government came to the conclusion that no having finally brought control of these strategic industries into public hands that it couldn't really surrender it to a supranational body a key part of that objection, which I didn't get into in the lecture had to do with the issue of democratic accountability and representation so for the aptly government during these discussions there was this idea that the high authority it was unelected, undemocratic at the time at nine officials I would later turn into the European Commission and so these were simply people who were appointed yet were given very significant powers over British and other countries strategic industries so for the aptly government it was much more a question of democratic accountability and really having effectively the people having control over the industry rather than a distant, unelected representative Any more questions in the audience? Gentleman over here I was just thinking we're a full nation university and we're talking about Britain's response is there any sort of sense of what the different were their different views in different parts the different nations in the periods that you've discussed? So that's an excellent question and I should probably apologise at this point I keep referring to Britain where of course I'm referring to the UK to the 124 nations so I think we see this especially in the nationalist movements that emerge so the Plaid Cymru, the Scottish Nationalists tend to oppose British membership in the European community in the 1975 referendum they campaign against it on the grounds that they're trying to win greater effectively greater sovereignty and so surrendering or transferring sovereignty from the UK to somebody else isn't really in their interests which contrasts of course with the SNP's policy notably today I don't think within cabinet level or the grassroots level that there were any very significant differences at least to the point that it informed cabinet decisions at this time which may simply suggest that these were taken less importantly at the time and we have another question at home I think so this is from Harriet she's asking if Luke could expand a little bit on the socialist position regarding the EEC given that you said that the left wing of the day weren't very keen on closer integration and she says she's curious to know if looking at that period can shed any light on why anti-EU sentiment these days has become more of a right wing position than a left wing one and I I don't have a ready answer to it I suppose one important factor during the period that we're looking at in the 1950s and 60s onwards is that this initial objection this fear that belonging to the European community meant that democratic socialism couldn't be pursued at the national level and this was one of the great fears of the Adelaide government I think throughout the 1950s and 60s we do see socialist governments in other members of the community who are able to pursue this with the steel and or coal industries which had similarly been nationalised in the early post-war period and so we don't see this level of interference it's not as if the high authority is intervening and saying no that policy is too left wing and so on and I think that puts a lot of those anxieties or puts those with those anxieties at ease within the Labour Party in the UK and as for why it's more associated with the right than the left that's an excellent question I think the question may be more about why it has come to be why is it that so much of the British right has come to latch on to this idea of national sovereignty and euroskepticism whereas on the left that existed but it's largely subsided since then I think it's very much a minority position within the Labour Party at least that the EU is a negative force for Britain Pardon? Yes Okay, do we have any more questions in the audience here? Yes, just a gentleman over there then Chris afterwards My question is in two halves and I say from a leave point of view and from a remain point of view what would you say is the main lesson from history for both sides, one pro leave and one pro remain That's a fun mental exercise The remain lesson I think is very clearly that I suppose throughout this period as I said the British policy and I think it was a rational policy to pursue at the time was preserving access to Britain's main trading partners and I think today it's like 53% of imports and 44% of exports are with the EU so erecting new barriers and tariffs are singularly not in the national interest and I suppose I could build on that for if a to take more of a pro leave position on this I suppose pointing to the fact that in the early 1950s Britain did about half of its trade with the Commonwealth comparable to the amount currently done with the EU today yet it was able to effectively well wasn't purely a decision of the British but those trade flows did change over time and they were able to find prosperity with other trading partners which had a much lower initial share of British trade initially although I personally remain unconvinced I thought by that lesson I had a question from Chris as well extra factors to what extent does the sort of British experience of Sue is and the millions perhaps at the time shocking embrace of African independence movements and the wind of change speech how much of that was part of an overall package of the foreign office deciding posts with wind of change that a reorientation of Britain's or the UK's place in the world was necessary an excellent point and you're absolutely right to situate it in that context that when Britain succeeds in 1937 there is a broad re-evaluation of Britain's foreign policy its overseas engagements, its empire and so on and from this comes a couple of years later a thorough assessment of effectively should Britain join the European community once it's set up in January 1958 and the results of that report come back in 1960 it's very clear that it's in Britain's interests to join the community rather than out, than remain out and that if Britain were to remain outside then its decline as seen in various examples would accelerate and continue Do you have any more questions in the audience here? We've got a few more minutes left. Yes, Neil. Can I just sort of pick you up on some of the comments you've made in other answers relating to the issue of sovereignty vis-à-vis the UK population I mean, why do you think it is that I mean, I guess you can sort of see that the sovereignty argument and the sort of limited nature of democracy within the EU structures is a plausible argument even if you don't find it completely persuasive it has persuaded quite a lot of people in this country I mean, why do you think, though, that that has been so much more persuasive to the UK population than it has to the 27 other populations of the EU? That's a very good question I'm one of my instincts is that Britain is the only member of states to have had an exit referendum and despite talks of a potential Brexit and Grexit and so on and I think at different points in time actually leaving seems to be a more popular option within individual member states and I think in the case of the Brexit referendum a number of factors notably the time it was held how the two campaigns were run of course were decisive but I think it was a number of factors which contributed to this outcome I would suspect that notwithstanding Britain's distinctive history as a member of the European community and the European Union I think if all the other 27 member states were to launch exit referendums I'm not entirely convinced that all 27 would necessarily result in votes to remain Any more questions from our audience over here? It's more of a comment really it was interesting when the Scots tried to break away the headline was better together the same people are now saying better apart I don't understand that but another thing I don't understand, a lady behind me I don't know who it was was talking about handing over this, that and the other from our country to them people don't seem to realise that we are them we are part of the European Union at the moment but it's always to them it's never explained that we are them I think there are a number of long term understandings of what Europe is that have evolved over the years in Britain such as that that Europe is over there and we're over here and we send money over there and so on that in some cases were encouraged and indulged by politicians for various reasons over the years and that all contributed to the referendum results in 2016 We've got time for one quick question from Annika before we wrap up Thanks but it's possibly also just a comment but I'm just struck by the importance of the second world war in all of this and how differently it impacted on this country and I think we talked earlier about learning lessons from history or in this case I think forgetting lessons from history and it just seems so much easier in this country to forget about the second world war whereas that is pretty much still impossible to do in France or in Germany so I think it is how Britain relates to its continental neighbours to the history of the 20th century and it is just fundamentally very different Absolutely and just a comment on that comment really but certainly when I was preparing for this lecture I didn't explain but the quotation of course with Europe but not other it comes from Churchill and I was doing a search around that and there seems to be a whole cottage industry so Churchill arguing and placing op-eds in various newspapers in the UK arguing what would Churchill have thought about Brexit and I mean there are, you can read these by the meter and various arguments about how Churchill of course would have backed to remain he would have backed no deal Brexit and everything in between so yeah I think that's an oversimplification of the lessons from history I think you can look at the same historical figure and draw radically different and mutually exclusive lessons from it Okay I think we're going to have to leave it there I know Richard has an announcement now about our next lecture in the series so I'll hand over to Richard again to finish for today I think we've grilled Luke enough Luke I've booked you an appointment tomorrow morning with the OU counselling service thank you all for coming again our next lecture is on the 6th of February it is making this realm of England an empire, the Tudors in Europe my colleague down there Neil Younger will be delivering it can I ask you to show your appreciation for Luke one last time he's done a great job, cheers