Microdomain Composition in Two-Phase Hydrogels

Hydrogels which form spontaneously from surface-active graft copolymers in solution are characterized by two distinct phases — a continuous phase consisting of water and the hydrophilic backbones of the polymer chains, and a dispersed phase composed of clusters of the hydrophobic side chains. The composition of these clusters, or microdomains, has been investigated using fluorescence probe techniques, and was found to depend on the composition of the solvent. The microdomain composition in turn influences the bulk network properties, since the microdomains act as linkage points in the network. In addition, hydrophobic solutes permeating the network are absorbed into the microdomains, permitting higher solute loading into these hydrogels than in equivalent volumes of water.