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Summary: Based on silsesquioxanes (SSO) derived from the hydrolytic condensation of [3-(glacildoxy)propyl]trimethoxysilane (GPMS), 20 wt-% tetraethoxysilane (TEOS) and titanium tetrabutoxide (TTB), two-layer SSO films were prepared for nanoindentation and nanoscratch tests. The tests were carried out to study the influence of different amounts of TTB in the two-layer hybrid films on hardness (H), elastic modulus (E) and scratch (S) testing profiles. The H profiles of the modified films showed two kinds of H corresponding to the two-layer structure. In the S testing profiles, all final-scan profiles did not absolutely coincide or overlap with the firstscan profiles. All S profiles revealed a fluctuanting characteristic and all S profiles can be divided into two regions in the horizontal displacement, because of the two-layer structure. The film containing an adequate amount of TTB (20 wt-%) was found to possess the largest H and E, as well as the best S resistance.

Summary: Three silsesquioxane (SSO) building blocks based on [3-(methacryloxy)-propyl]trimethoxysilane (MPMS), [(3-glycidoxy)propyl] trimethoxysilane (GPMS), (vinyl)trimethoxysilane (VMS) and modified with 15 wt-% tetraethoxysilane (TEOS) were prepared using hydrolytic condensation. The hardness, elastic modulus and harmonic contact stiffness for three films [f-MTSSO (film-MPMS-TEOS-SSO), f-GTSSO and f-VTSSO] and bulks (b-MTSSO, b-GTSSO and b-VTSSO) derived from the three SSOs were tested by instrument-indentation testing. Different profiles of nanomechanical properties of the films can be attributed to a different functionality and the functionated structure of the different SSOs. The f-MTSSO shows better mechanical properties which are higher than the other two films containing more OH or OCH 3 groups. For the f-GTSSO with a bulky organic substituent, the unsatisfactory properties resulting from ring opening during hydrolytic condensation and an incomplete crosslinking network are discussed. However, the nanomechanical properties of the three bulks are very different from the corresponding nanomechanical properties of their films: b-VTSSO possesses the best nanomechanical properties (note: not b-MTSSO) among three bulks due to the differences in reaction conditions and chain less flexibility which are also discussed.

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