This paper describes a novel chemical method for preparing SiO2/TiO2 Janus particles. First, polystyrene （PSt）/SiO2 particles with a raspberry-like structure are prepared by electrostatic assembly. The influences of the reaction time of sulfonation and the treatment times of polyelectrolyte solutions （PDADMAC, PSS） on PSt and SiO2 are investigated with respect to the surface charge density of the particles. SiO2/TiO2 Janus particles are then obtained by hydrolysis of butyl titanate on the surface of PSt/SiO2 particles followed by a calcination process. Particle size analyzer, Zeta potential instrument, FTIR, TEM and SEM are used to characterize the particle size, the amount of charge on the surface of PSt and SiO2 particles and the compositions and morphologies of PSt/SiO2, SiO2/Ti02 and PSt/SiO2/Ti02. The diameters of the PSt, SiO2, PSt/Si02 and SiO2/Ti02 particles are 2.0 t^m, 303 nm, 2.7 bcm and 330 nm, respectively.
Baoliang ZhangQiuyu ZhangHepeng ZhangXinlong FanDezhong YinXiangjie LiWei Li
This article presents a facile approach to preparation of polystyrene/silver （PS/Ag） asymmetric hybrid par- ticles. In this method, polystyrene/polyglycidyl methacrylate （PS/PGMA） Janus particles were synthesized via internal phase separation triggered by evaporation of dichloromethane （DCM） from PS/PGMA/DCM- in water emulsion droplets. Then, the Janus particles were aminated and sequentially carboxylated to obtain PS/PGMA-NH2 and PS/PGMA-COOH particles. Ag＋ self-assembled on the surface of PGMA hemi- sphere of the functionalized PS/PGMA particles by coordinating with amine/carboxyl. PS/Ag asymmetric hybrid particles with 7.29 wt% of Ag were obtained by reduction of Ag＋, Scanning electron microscopy, energy-dispersive X-ray spectroscopy and transmission electron microscopy results confirmed that Ag was asymmetrically distributed on the surface of polymer particles.
Xinlong FanQiuyu ZhangHepeng ZhangBaoliang ZhangChunmei LiXiangjie LiXingfeng Lei
