BILAYER STRUCTURES IN SIDE-CHAIN LC COPOLYMERS

Random copolymers AxB1-x of two comonomers having sufficiently long an d different side chains can form double comb conformations wherein the two types of side chains are demixed. These copolymers can build up b ilayer structures, with alternating layers filled by the side chains o f A and B. The structures and transition temperatures of such copolyme rs were studied, by DSC, light microscopy, and X-ray scattering. The m ain chain is always methacrylic; the side chains consist of spacer dec oupled mesogens or of n-alkyl sequences. Three rings in the mesogenic side chains and ten methylene groups in the alkyl side chains are requ ired for good bilayer structures. Calculations show that the bilayer s tructure is not hindered by the random comonomer sequence order in the AxB1-x chains, unless x is very large or small.