Preparation of Temperature-Responsive Janus Nanosheets and Their Application in Emulsions

In this study, patch-structured C8/CHO template microspheres were successfully synthesized through in situ reduction and sol–gel reactions, providing a reusable platform for subsequent modifications. Based on these templates, temperature-responsive PW12O403−-PILs/PNIPAM Janus nanosheets were prepared via sequential Schiff-base coupling and ATRP. Structural characterizations (XRD, SEM, TEM, FTIR, and TGA) confirmed successful functionalization and nanosheet formation. The PNIPAM moiety endowed the nanosheets with temperature responsiveness, while the incorporation of polymerized ionic liquids and phosphotungstate anions further enhanced amphiphilicity and dispersion stability. When applied as particulate emulsifiers in water/toluene systems, the Janus nanosheets formed stable Pickering emulsions at elevated temperatures and underwent reversible emulsification–demulsification upon temperature cycling. These findings demonstrate the potential of PW12O403−-PILs/PNIPAM Janus nanosheets as smart emulsifiers for responsive separation and formulation technologies.