Study of the mechanical properties of two organic-inorganic hybrid systems: GPTMS/colloidal silica and GPTMS/TEOS

This work investigates the mechanical properties of different scratch resistant coatings, namely, a mixture of 3-glycidoxypropyltrimethoxysilane (GPTMS) with either colloidal silica particles or tetraethoxysilane (TEOS). Coatings were prepared by the hydrolysis and the condensation of the precursor's alkoxide (sol-gel process) with thermally catalyzed polymerization of epoxy ring of GPTMS. Dip deposition techniques were used on silicon substrate. The nanoindentation technique was used to analyze the force required to indent the coating with a diamond tip. At low forces, this technique, based on indentation depth, predicts the hardness and the elastic modulus of the coating, while at higher forces, cracks appear. Another analysis based on geometric approach, namely, the crack length, allows the determination of both coating and interface toughness. (C) 2012 Elsevier B.V. All rights reserved.