Two Gel States of a PEO-PPO-PEO Triblock Copolymer Formed by Different Mechanisms

Abstract

Two gel states of a PEO-PPO-PEO (Pluronic P103) triblock copolymer in water are investigated using small-angle X-ray scattering, rheology and differential scanning calorimetry. The first gel state turns out to be the hexagonal microphase while the second gel state, showing turbidity change with four distinct regions, is somewhat disrupted. The second gel is moreover not thermoreversible as evidenced by rheology. Based upon the present study, two different gelation mechanisms for aqueous PEO-PPO-PEO solutions are proposed.