Solution Characterization of PEGL, a Water-Soluble, Non-Ionic, Helical Polypeptide

In this work, a non-ionic, water-soluble rigid rod polymer was investigated for viability in replacing organic-soluble rigid rod polymers as these legacy rigid polymers require difficult solvents. Producing a rigid, water-soluble polymer that does not suffer from aggregation or ionic effects is a difficult proposition. Herein, the synthesis of a poly(lysine) with a short ethylene glycol side chain, PEGL, was duplicated, based on previous work by Deming et al. and characterized by various techniques. It was discovered that PEGL suffers from aggregation, evidenced by dynamic and static light scattering experiments that showed non-ideal rigid rod behavior and multiple decay rates. PEGL also showed a changing lower critical solution temperature when varying salt concentration. Although PEGL can exhibit a double helix conformation and has non-ionic side chains, the propensity for aggregation precludes PEGL from being used for fundamental polymer investigation.