Surface Modification of Indium Tin Oxide Nanoparticles to Improve Its Distribution in Epoxy-Silica Polymer Matrix

A semiconducting nanoparticle indium tin oxide (ITO) was modified with silane groups and for this purpose trimethoxysilane (TMOS) precursor was used under specific experimental conditions for surface modification of ITO nanoparticles. It is found that the modification of ITO nanoparticles increases the interactions between the filler and the matrix and subsequently improves the distibution of indium tin oxide nanoparticles in the polymer matrix. The epoxisilica polymer matrix was produced using trimethoxysilane and 3-glycidyloxypropyl trimethoxysilane precursors and ethylenediamine (EDA) as curing agent at low temperature by sol-gel process. The sol-gel process was very useful due to its easily controllable process، solution concentration and homogeneity without using expensive and complicated equipments in comparison with other methods. Then، Fourier transform infrared (FTIR) spectroscopy was employed to study the formation of Si-O-Si and Si-OH groups on ITO nanoparticles. X-Ray diffraction (XRD) technique and thermal gravimetric analysis (TGA) were employed to investigate the modification and weight loss of the modified ITO، respectively، as an indication of the presence of organic groups on these nanoparticles. The separation analyzer tests were performed to check the stability of the nanoparticles suspension and it revealed that due to better interaction of nanoparticles with the polymer matrix the stability of modified ITO suspention is higher than the unmodified sample. The morphology and particle distribution were determined by scanning electron microscopy (SEM). It was found that the distibution of modified indium tin oxide in epoxy-silica polymer matrix was improved in comparison with pure ITO.