Preparation Of Hollow Organic Silicone Microspheres With Regular Morphology By Soft Templating Method

Hollow microspheres have broad application prospects in many fields such as catalysis,drug transportation,energy storage and photonic crystals due to their unique structural characteristics such as large specific surface area,low density and high load capacity.Compared to other organic fluids,poly(dimethylsiloxane)(PDMS)emulsions are widely used in fields like waterproofing surfaces,antistatic coatings,and defoaming agents because of its highly hydrophobicity of the droplets and better chemical stability.In addition,since the PDMS emulsions contain a large amount of siloxane molecules,they can also be used as soft templates to prepare hollow organic silicone microspheres.However,different emulsifiers have a great influence on the monodispersity,particle size and coating results of the emulsions.In this paper,monodisperse poly(dimethylsiloxane)(PDMS)oil in water emulsions with controllable particle size were prepared by using different monomers and emulsifiers.Then,the emulsions were coated as templates,and finally washed with ethanol to obtain hollow silicone microspheres with regular morphology.Firstly,monodisperse poly(dimethylsiloxane)(PDMS)oil in water emulsions were perpared through hydrolysis-polymerization under basic conditions by using dimethyldiethoxysilane(DMDES)as monomer and Tween80,Span80,F127,CTAB as different emulsifiers.The effects of emulsifier type,emulsifier HLB value,reaction time and monomer content on the emulsion were studied.When Tween80 and Span80 were used as compound emulsifiers,the HLB value is 13 and the reaction time is 12 h,monodisperse PDMS emulsion with controlled particle size could be prepared.The particle size regulation range is 374~575 nm,and the particle size distribution index(PDI)is less than 0.1.Hollow microspheres with regular morphology could be obtained by coating with the emulsions.The hollow microspheres have a particle size about 590 nm,but their regular morphology is poor and the particle size can't be controlled.Secondly,according to the above research results,using dimethyldimethoxysilane(DMDMS)as a monomer,Tween80 and Span80 as compound emulsifiers.Highly monodisperse PDMS oil-in-water nanoemulsions with controlled diameter could be obtained when the emulsifier HLB value is and reaction time is 6 h.The particle size of the emulsion could be turned from 320 to 472 nm,and the PDI of the emulsion is less than 0.05.Then,monodisperse hollow microspheres with regular morphology and controlled particle size could be obtained by using the emulsion as a template.The particle size regulation range is 500~710 nm and the PDI of the microspheres is less than 0.1.Finally,hollow microspheres were characterized by EDS and FTIR.The results showed that the hollow microspheres contained silicon,oxygen and carbon,and the content decreased in turn.The composition of the hollow microspheres was organic silicone.