Preparation of poly-(NIPAM) grafted hybrid silica particles with hollow structure in emulsion

The successful preparation of hybrid silica particles was studied using 3-(trimethoxysilyl)propyl methacrylate (TMPM) and poly(N-isopropylacrylamide) (poly-(NIPAM)) in W/O (water-in-oil) emulsion. In general, hollow silica materials were made using a template method that was needed a process of template removal. However, in this paper, hollow particles grafted with organic materials were synthesized directly and the structure of particles was controlled by adjusting ratio of reactants. A large amount of thermo-responsive polymer such as poly-(NIAPM) can be formed at the surface of hollow silica particles because silica substrates have many methacrylate functional groups at surfaces. Detailed characterization of the hybrid silica particles was investigated using scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) to elucidate the morphologies and properties of the hybrid silica particles.