A. Levent Demirel, Koc University
Self-organization of polymers
Polymeric molecules self-organize into various structures and morphologies mainly due to selective interactions. For two thermodynamically immiscible polymers A and B attached by a covalent bond, micro-phase separated ordered equilibrium morphologies depend on the length of the polymers and their interaction. By attaching side chains to one of the polymers (say A), it is possible to change the morphology from hexagonal arrangement of cylinders of one polymer (A) in the matrix of the other (B) to lamellar morphology (ABBA) and to inverted hexagonal morphology (cylinders of B in the matrix of A). In liquids, selective interactions of polymers with solvent molecules are critical. The self-organization of a water soluble polymer above its lower critical solution temperature into nanofibers by directional crystallization will be discussed in terms of hydrophobic interactions, dipolar interactions and backbone salvation.