Understanding cationic polyelectrolyte thermogels with varying charge densities toward biomaterials design

Abstract Polyurethane thermogels are attractive materials for biomedical applications due to their reversible temperature‐controlled gelation that allows for in situ gelation at physiological temperatures. However, traditional thermogels are limited by their lack of ionizable groups, rendering them electroneutral. Herein, pendant amine groups were incorporated into amphiphilic polyurethane copolymers to obtain cationic polyelectrolyte thermogels. Polyurethane thermogels, unlike other cationic thermogels, have greater control over functional group density, enabling customization of charge density and resulting properties. This study elucidates the influence of cationic charges on their self‐assembly and thermogelling properties. Notably, thermogels with greater cationic group density exhibit amplified pH responsiveness, enabling the material's pH sensitivity to be tailored. These findings provide critical insights into the hierarchical self‐assembly mechanism, which dictates the thermogelling behavior and properties of cationic, amphiphilic copolymers, offering a deeper molecular understanding necessary for designing polyelectrolyte thermogels for specific biomedical applications.