A Method For The Preparation Of Hollow SiO₂ And TiO₂ Particles

Recently,synthesis of inorganic hollow particles ranging from nanometer to micrometer scale is attracting increased interests.The successes in synthesis of hollow structures gave the ability to customize their mechanical,optical,electrical,chemical,and other properties.These successes,in turn,became the incentive to the growing list of applications.However,it should be noted that a high quality hollow particles(for example,not agglomerated,and with controlled sizes)is necessary in many cases for both fundamental research and practical applications.A review of the literature in this area shows that the methods of producing hollow particles of such high quality are still very limited,and that even if these methods can be found,they are suitable for small kind of the materials.Due to the increasing interest(both from scientific and technological point of view),in hollow particles;in the present research we focus on several aspects regarding this type of particles:1.P(St-co-AA),P(St-co-NaSS),P-(St-co-AA)modified with KH570,copolymer templates were prepared by soap-free emulsion polymerization,with particles size of about 250 nm,78 nm and 290 nm,respectively.2.Monodisperse SiO2 particles with controllable diameters and shell thicknesses were prepared by using untreated anionic P-(St-co-AA)particles prepared by soap-free emulsion polymerization as a template.3.PAANa nanoparticles were prepared through PAANa aggregating in ethanol by nanoprecipitation,then silica shell was formed on the templates were through sol-gel process.Hollow particles were obtained by removal of the water-soluble templates by washing with water.Hollow silica particles with controllable diameters and thicknesses can be obtained ultimately under the control of PAANa solution concentration,TEOS and NH4OH amount.4.TiO2 particles were prepared by using anionic polymer templates.Different factors affecting coating process were investigated.