Spherical polyelectrolyte brushes （SPBs） with PS core and poly（acrylic acid） （PAA） brushes were prepared and analyzed by SAXS in this article. A radial electron density profile of SPB was brought up, which fits well with the SAXS result and shows a core-shell structure. The effect of pH on SPB form was represented by SAXS and it proves that the chains of SPB will stretch in response to increased pH owning to the increased electrostatic repulsion. SPBs immobilized with magnetic nanoparticles or bovine serum albumin （BSA） were prepared and analyzed by SAXS as well. SAXS could characterize the changes of electron density inside brushes of SPBs due to the immobilization of magnetic nanoparticles or BSA. This provides significant supports for further application of immobilized metal nanoparticles or proteins.
Xuan-ji YuWei-hua Wang李莉Xu-hong GuoZhi-min ZhouFu-chen Wang
Bifunctional spherical polyelectrolyte brushes （SPBs） with tunable thermo-and pH-sensitivity are synthesized by combining therrno-controlled emulsion polymerization and photo-emulsion polymerization. They consist of a spherical polystyrene core and a shell of mixed brushes of poly（N-isopropylacrylamide） （PNIPAM） and poly（acrylic acid） （PAA） whose composition can be easily modulated by the dose of monomers. The kinetics of SPB synthesis as well as their size change with temperature and pH is determined by dynamic light scattering （DLS）. The scanning electron microscopy （SEM） images show that the bifunctional SPBs have a defined spherical morphology with a narrow size distribution.
