SYNTHESIS AND CHARACTERIZATION OF POLYMER BRUSHES CONSTRUCTED ON SiO2 SURFACES BY ELECTROSTATIC-ASSEMBLY

Sodium sulfonate terminated polystyrene (PS-SO3Na) was synthesized by atom transfer radical polymerization of styrene with 2'-(p-sulfophenyl)ethyl 2-bromoisobutyrate ao initiator, and the resulting polymer reacted with NaOH. The initiator was lyntheaized front 2-phenylethanol and 2-bromoisobutyryl bromide. Polymer brushes constructed on the surface of cationically functionalized SiO2(SiO2-CBAFS) were prepared via electrostatic-assembly between PS-SO3Na and SiO2-CBAFS, IR, H-1-NMR, TG, TEM, AFM, GPC and water contact angle were used to characterize the structure, the assembly amount and the regularity of the assembly system. The results show that PS-SO3Na can be synthesized with 2'-(p-sulfophenyl)ethyl 2-bromoisobutyrate successfully, the assembly efficiency is increased in some extent with the polymer terminated 100% sodium sulfonate, and the amount of polymer brushes assembled on the surface of SiO2 is as high as 34.4%; white layers can be observed at the surface of SiO2 colloid particles with TEM, and the dispersion of SiO2 is modified obviously; the descent of water contact angles of the samples below 4 degrees when the rinsed solvents altered from THF to H2O; the decorate effect of SiO2 is preferable when the molecular weight of PS-SO3Na range from 1.5 x 10(4) to 3.6 x 10(4) and the molar concentration of polymer solutions range from 2.5 x 10(-5)mol/L to 5 x 10(-5) mol/L with the analysis of the results of TG, AFM and water contact angles.