Mechanical Properties of Sol-Gel Inorganic-Organic Hybrid Films in Nanoindentation

Methylsilsesquioxane films were formed on glass substrates by dropping a sol prepared from methyltriethoxysilane and then heat-treated in an oven. Nanoindentation test was performed to assess the elastoplastic properties of the films, including the relative residual depth xi(n) Meyer hardness H-M, work-of-indentation W, and the elastic modulus E'. The values of xi(r), H-M and W-I were obtained by a Berkovich indenter and E' was determined by a spherical indenter on the basis of Hertz elastic theory., decreased with the increase in the heat treatment time, whereas H-M, W-I and E' significantly increased with the time. The changes in the mechanical properties with the heat treatment time well reflected the evolution of the Si-O-Si network structure in methylsilsequioxane film.