Functional film by trigger-free self-assembly of adhesive soft microgels at skin temperature

Abstract Trigger-free self-assembly of oligo(ethylene glycol) OEG-based responsive microgels is for the first time described via simple solvent evaporation process at skin temperature and ambient pressure. This unique behaviour is attributed to the intrensic OEG microgel structure and properties due to a negative glass transition temperature, a high adhesion energy, an elastic mechanical property and a high interpenetration of microgels, combined in an all-in-one building block. Furthermore, the encapsulation of magnetic nanoparticles (NPs) into the OEG-based microgels introduced interferential photonic and magnetic properties to the films. These microgels exhibiting simultaneously spontaneous film-forming and colored photonic properties open up the development of a unique easy-to-handle material for cosmetic applications, but also smart patches for healthcare or medicine.