Dense oxycarbosilane films:
G_c = 15-17 J/m²

The fracture energies of the OCS films vary with film density as expected, but are considerably higher than those of their CDO and MSSQ counterparts. More precisely, porous Et-OCS films present adhesive and cohesive fracture e nergies, which are 2-3 times higher than those obtained for CDO and MSSQ materials. For instance, at a density of 0.85 g.cm^-3 (k = 2.05), G values measured for Et-OCS are 2.83 and 3.19 J.m^-2 (adhesive and cohesive, respectively), as compared to 1.32 and 1.51 J.m^-2 for CDO and MSSQ. Interestingly, when compared to materials which have been toughened with UV treatment, Et-OCS films still exhibit higher adhesive fracture energies, suggesting that these materials could be integrated without adding this processing step. Moreover, unexpectedly the cohesive fracture energies measured for dense Me-OCS and Et-OCS films (4.96 and 6.95 J.m^-2 respectively), are actually higher than those measured for pure silica (4 J.m^-2).

References:
Dubois et al., Adv. Mat. 2007, 19, 3989-3994.
E.P. Guyer et al. J. Mater. Res. 2006, 21, 882.