Preparation And Characterizations Of Amorphous SiO₂ Nanoparticles

Nanoglass is a solid material made up of nanometer-sized glassy regions connected by glass/glass interfaces with a large number of free volumes,which may have special physical characteristics and chemical reactivity.SiO₂ nanoglass may be with different properties from ordinary glass due to the special structure to solve the problem of the brittleness and broaden the application of glass.Therefore,it is necessary to prepare amorphous SiO₂ nanoparticles which are completely disperse,spherical in shape,and fine in particle size.In this work,we synthesized amorphous SiO₂ nanoparticles via a microemulsion method and investigated the effects of the amount of surfactant,the amount of co-surfactant,and the amount of starting material on the dispersion,morphology,and particle size.Microemulsion method is an important method for preparing amorphous SiO₂ nanoparticles.In present work,fine disperse amorphous SiO₂ nanoparticles were synthesized using tetraethyl orthosilicate?TEOS?as starting material,n-hexanol as co-surfactant,cyclohexane as organic solvent,ammonia?28-30 wt%?as catalyst,polyoxyethylene?10?tertoctylphenyl ether?TX-100?,tert-OCLylphenoxy poly?oxyethylene?ethanol?TX-114?or polyoxyethylene?20?cetyl ether?Brij-58?as surfactant via a facile microemulsion method and subsequent calcination.The structure,composition and morphology of the samples were characterized by XRD,TEM,EDX,and FT-IR.The results show that the nanoparticles prepared in TX-100/n-hexanol/cyclohexane/ammonia reverse microemulsion are pure amorphous SiO₂ nanoparticles,and these nanoparticles are irregular in shape,nearly disperse with weak agglomeration,large in size with an average size of 39 nm,and wide in particle size distribution from 28 to 56 nm at 4.2 mL TX-100,8.3 mL n-hexanol,6.3 mL TEOS,1 mL ammonia,and 1.3 mL water.If prepared in TX-114/n-hexanol/cyclohexane/ammonia reverse microemulsion,the nanoparticles are pure amorphous SiO₂ nanoparticles,and these nanoparticles are irregular in shape,completely disperse,small in size with an average size of 21 nm,and wide in particle size distribution from 10 to 34 nm at 3.5 mL TX-114,5.0 mL n-hexanol,6.3 mL TEOS,1 mL ammonia,and 1.3 mL water.If prepared in Brij-58/cyclohexane/ammonia reverse microemulsion,the nanoparticles are pure amorphous SiO₂ nanoparticles,and these nanoparticles are spherical in shape,completely disperse,fine in size with an average size of 21 nm,and narrow in size distribution from 15 to 26 nm at 3 mmol Brij-58,0 mL n-hexanol,1 mL TEOS,and 1.2 mL ammonia.