Preparation and characterization of temperature‐ and pH‐responsive diblock copolymers and their silica‐coated nanoparticles

摘要

> Multiresponsive amphiphilic poly( N , N ‐dimethylaminoethyl methacrylate)‐ b ‐poly( N ‐isopropylacrylamide) (PDMAEMA‐ b ‐PNIPAM) was successfully synthesized by reversible addition‐fragmentation chain transfer polymerization. Poly( N , N ‐dimethylaminoethyl methacrylate)‐ b ‐poly( N ‐isopropylacrylamide) has thermal and pH stimuli responsiveness. Their lower critical solution temperature and hydrodynamic radius can be adjusted by varying the copolymer composition, block length, solution pH, and temperature. In addition, a convenient method has been established to prepare cross‐linked silica‐coated nanoparticles with PDMAEMA‐ b ‐PNIPAM micelles as a template, resulting in good organic/inorganic hybrid nanoparticles defined as 175 to 220?nm. The structure and morphology were characterized by proton nuclear magnetic resonance ( ₁ HNMR), Fourier‐transform infrared spectroscopy (FT‐IR), transmission electron microscopy (TEM), and transmission electron microscopy‐energy dispersive X‐ray spectroscopy (TEM‐EDS).