Bilayer Formation by Aggregation of Polymeric Amphiphiles

Acrylic monomers possessing dialkyl(double-chain) and single-chain tails were prepared. The tail portions are made of characteristic structures common to the hydrophobic portion of bilayer-forming amphiphiles. They are dialky(C12 to C18)chains connected by amide, glyceryl ether or glutamate moieties or single chains with rigid aromatic segments(azobenzene and biphenyl). These monomers were copolymerized by azobisisobutyronirile with hydrophilic monomers such as acrylamide, acrylglycinamide and other charged monomers. Copolymers which contain as much hydrophobic units as possible were dispersed in water by sonication. They formed the bilayer aggregate spontaneously, as confirmed by electron microscopy, differential scanning calorimetry and small-angle laser light scattering. On average, 10 to 10 polymer molecules aggregate to form huge(molecular weight, 106–108) bilayer aggregates. The bilayer assemblage of the polymeric amphiphiles appears to be inferior to that of the small-molecule counterparts, although introduction of the spacer between the polymer main chain and the side-chain portion improves the bilayer orgainzation.