Prolate and Temperature‐Responsive Self‐Assemblies of Amphiphilic Random Copolymers with Perfluoroalkyl and Polyoxyethylene Side Chains in Solution

Two amphiphilic random copolymers, PEGMAx‐ co ‐FAy ( x  = 90 and 70 mol%), are synthesized by ATRP and their solutions are investigated as a function of solvent, concentration, and temperature by DLS and SANS analyses. Both copolymers self‐assemble in nanostructures by single‐chain folding in water solutions over a wide range of temperatures. The values of the DLS hydrodynamic radius and the SANS radius of gyration are found to be ≈4 nm and ≈3.4–3.7 nm, respectively. Moreover, SANS shows the self‐folded nanoassemblies to be prolated spheroids with a ratio of polar/equatorial axes of ≈5:1 for PEGMA90‐ co ‐FA10 and ≈2:1 for PEGMA70‐ co ‐FA30. On heating above a critical temperature T c , multichain microassemblies are formed that revert back to nanoassemblies on cooling below T c . This temperature‐responsive transition is fully and sharply reversible.