 Other surfactants produced on a particularly large scale are linear alkylbenzene sulfonates (1700 kton/y), lignin sulfonates (600 kton/y), fatty alcohol ethoxylates (700 ktons/y), and alkylphenol ethoxylates (500 kton/y).In the bulk aqueous phase, surfactants form aggregates, such as micelles, where the hydrophobic tails form the core of the aggregate and the hydrophilic heads are in contact with the surrounding liquid.Other types of aggregates can also be formed, such as spherical or cylindrical micelles or lipid bilayers.