It isn't a photonic crystal, but the opal is a form of this type of system which can self assemble to form photonic crystals. Removal of electrostatic barriers from these systems, such as by adding salts, can lower the zeta potential and cause them to destabilize in a process called flocculation. Examples of these types of systems include sols and gels, and unlike a similar mixture, these will not settle under gravity. Li
It isn't a photonic crystal, but the opal is a form of this type of system which can self assemble to form photonic crystals. Removal of electrostatic barriers from these systems, such as by adding salts, can lower the zeta potential and cause them to destabilize in a process called flocculation. Examples of these types of systems include sols and gels, and unlike a similar mixture, these will not settle under gravity. Light is scattered by these mixtures in a process similar to Rayleigh scattering called the Tyndall Effect. For 10 points, name this type of dispersion midway between a solution and a suspension.
It isn't a photonic crystal, but the opal is a form of this type of system which can self assemble to form photonic crystals.
{Colloid}s [prompt on "foam," "emulsion," "sol," or "gel" before mention, prompt on "dispersion" before mention]