Characteristics of Thin Films Synthesized from Colloidal Silica-Silane Sols

Three kinds of colloidal silica (CS)/silane sol solutions were synthesized by using three kinds of CS at different reaction time. Sol solutions were prepared from 1034A CS/methyltrimethoxysilane (MTMS), HSA CS/MTMS and LS CS/MTMS materials. In order to understand their physical and chemical properties, sol-gel coating films were fabricated on glass. Coating film on glass, obtained from 1034A/MTMS sol, had high contact angle and much enhanced flat surface in comparison with those of HSA/MTMS and LS/MTMS sols. Enhanced surface properties were observed in the case of sol solutions left for 7 days. With increasing reaction time in sol solutions, surface free energy and roughness in coating films decreased. Good thermal stability was observed in all used films, i.e., no thermal degradation up to 550°C. In the case of 1034A/MTMS coating film, thermal degradation did not occur up to 600°C. In addition, microhardness of 1034/MTMS coating film was higher than those of HSA/MTMS and LS/MTMS due to active networking and surface treatment reactions between 1034A and MTMS.