Understanding the Temperature-Responsive Self-Assemblies of Amphiphilic Random Copolymers by SANS in D2O Solution

The self-assembly behavior, in aqueous solution, of amphiphilic methacrylic random copolymers with perfluoroalkyl and polyoxyethylene side chains and the morphology of the resulting nanostructures are investigated by small-angle neutron scattering (SANS). The results allow to clarify the effect of temperature on the self-assembly features of copolymers and the structural morphology of both unimer single-chain entities and larger multi-chain aggregates of unimers. Shape, flexibility, and size of the aggregates are proved to be modulated by temperature and copolymer composition. The existence of three distinct phases of self-assembled structures is pointed out as a function of increasing temperature: 1) globular unimers; 2) coexistence of extended unimers and aggregates; and 3) aggregates, which overall show full reversibility in a wide range of copolymer concentrations.