Highly sensitive multiresponsive photonic hydrogels based on a crosslinked Acrylamide- N-isopropylacrylamide (AM-NIPAM) co-polymer containing Fe3O4@C crystalline colloidal arrays

Multiresponsive photonic hydrogels (MRPHs) were prepared by magnetically controlled self-assembly of Fe 3 O 4 @C nanoparticles and these are sensitive to temperature, humidity, compression, tension and ethanol. This exhibits brilliant structural color thanks to the combination of AM and NIPAM monomers. Along with the increase of compression and tension on the MRPHs, the reflection peak of the samples blue shifts. When exposed MRPHs in environments with different humidity, its structure color red shifts as the humidity increases from 33% RH to 95% RH. Besides, the reflection peak redshift was observed when the MRPHs was immersed in absolute ethyl alcohol. This work may provide a new way to prepare smart photonic hydrogel with integrated functions of mechano-, humidity-, temperature- and solvent- responses.