Self-Templated Generation of Triggerable and Restorable Nonequilibrium Micelles

Conditional variations can lead to micellar transformations resulting in various (equilibrium) morphologies. However, creating differently shaped assemblies under the same final conditions (same ingredients, composition, temperature, etc.) is challenging. We present a thermoresponsive polyelectrolyte system allowing a pathway-dependent preparation of kinetically stable spherical star-like or cylindrical micelles. In more detail, a temperature-induced structure switch is used to generate equilibrated interpolyelectrolyte complex (IPEC) micelles of different morphologies (templates) below and above the lower critical solution temperature in the presence of plasticizer (salt). Then, lowering the salt concentration at a specific temperature kinetically freezes the formed IPECs, keeping the respective microstructural information encoded in the frozen IPEC also at other temperatures. Hence, different nonequilibrium morphologies at the same final conditions are provided. The salt-triggered transition from nonequilibrium to equilibrium micelles can be repeated for the same sample, highlighting a system with an on-demand changeable and restorable structure.