POLYMORPHISM OF (QUASI) 2-DIMENSIONAL MICELLES

Langmuir films of block polyelectrolyte surface aggregates formed at the air-water interface have been visualized as Langmuir-Blodgett films using transmission electron microscopy. The morphologies adopted by these (quasi) 2-D aggregates are critically dependent upon the ratio of the hydrophobic and hydrophilic block sizes. Three morphologies are observable (starfish, rod, and planar) in polystyrene/decylated poly(vinylpyridinium) block polyelectrolytes. Each particular morphology is observed within a well-defined composition range. Parallel polymorphism in 3D aggregates of block copolymers and small molecular weight amphiphiles suggest that the rules governing self-assembly in 2D and 3D and both small and large molecular weight molecules are qualitatively quite similar.