A novel quaternized-chitosan-modified reduced graphene oxide（HACC-RGO） combined the adsorption advantages of RGO and 2-Hydroxypropyltrimethyl ammonium chloride chitosan（HACC）. The adsorption property of HACC-RGO sheets for methyl orange（MO） was demonstrated and compared with RGO and HACC. The removal ratios of HACC-RGO sheets reached 92.6% for MO after a 24 h adsorption. The adsorption kinetics, isotherms and thermodynamics were investigated to indicate that the kinetics and equilibrium adsorptions were well-described by pseudo-second-order kinetic and Freundlich isotherm model, respectively. The thermodynamic parameters suggested that the adsorption process was spontaneous and endothermic in nature. Moreover, monodisperse HACC-RGO/CS beads were fabricated by the microfluidic method. The adsorption and desorption of HACC-RGO/CS beads for MO were studied. After three adsorptiondesorption cycles, the adsorption capacity remained above 55% and the desorption capacity was not below 70%. The HACC-RGO/CS beads can be reused and have great potential applications in removing organic dyes from polluted water.
The gradient copolymers of acrylic acid and trifluoroethyl methacrylate（coded as P（TFEMAgrad-AA）） were synthesized via reversible addition-fragmentation transfer（RAFT） emulsifier-free emulsion polymerization. The spontaneous batch feeding approach was used to control the gradient chain sequence. Transmission electron microscopy（TEM） analysis revealed that the P（TFEMA-grad-AA） can self-assemble to form spherical micelles, rodlike micelles or vesicles in selective solvents. Morphological transition of the P（TFEMA-grad-AA） micelles was sensitive to the water content of the dioxane/water mixed solvent. More interestingly, Ag nanoparticles（NPs） were encapsulated by the P（TFEMA-grad-AA） micelles during the selfassembly process. The gradient chain sequence made the Ag NPs easily enter the core of the micelles, even when P（TFEMA-grad-AA） had less hydrophobic fluoro-units and more hydrophilic units. TEM images with energy dispersive spectrometer indicated that the nanocomposite micelles consisted of a Ag NPs core and a gradient copolymer shell.
