Preparation And Properties Of PH Responsive Janus Nanosheets

Janus materials have been of interesting due to their functional diversity and wide application. Janus materials prepared from polymers may possess flexibility and responsibility. A pH-responsive hollow polymer nanosphere was prepared and crushed to give Janus nanosheets. The preparation method is universal to some extent. Magnetic labeling showed that the nanosheets were strict partition. Zata-potentiometric analysis and SEM demonstrate that Janus nanosheets were pH responsive and they can be used as emulsifierto stabilize oil/water emulsion.When the pH is 2, the emulsion effect is the best. The details are as follows:1. the SiO2 nanoparticles were prepared by the "Stober" method and surface fuctionalized with making the surface amination, followed by translating the amino groups to hydroxyl group. Ring-opening polymerization of lactide was initiated by the hydroxyl groups and grafting polylactic acid (PLA) hydrophobic polymer layer on the template surface.Then the terminal PLA groups were bromide-fuctionalized, and the abtained nanoparticles were used to initiate the polymerization diethylamino ethyl methacrylate(DEAEMA) through the ATRP. Ethylene glycol dimethacrylate ester (EGDMA) was used to crosslink the polymer layers. Etching SiO2 template with HF, pH responsiveness Janus hollow nanospheres were obtained. Finally the Janus nanosheets were formed after crushing of the hollow nanospheres. FTIR, TGA, EDX, XPS, TEM and SEM were used to confirm their composition and morphology.2. paramagnetic ferroferric oxide nanoparticles(Fe3O4) were prepared and absorbed on the different suface of the Janus nanosheets to demonstrate that the nanosheets is strict partition. Zata- potentiometric analysis and SEM demonstrate that Janus nanosheets were pH responsive and they can be used as emulsifierto stabilize oil/water emulsion.When the pH is 2, the emulsion effect is the best.