Low surface free energy cyanate ester-silica hybrid (CE-SiO2) nanomaterials for low k dielectric applications

The present work addresses the synthesis of 1,4-bis(2-(4-hydroxyphenyl)-2- propyl)benzene based cyanate ester-silica hybrid (CE-SiO₂) nanomaterials by an in situ sol-gel method. The nanomaterials are synthesized using a 1,4-bis(2-(4-cyanotophenyl)-2-propyl)benzene [CE] (organic phase) monomer and tetraethoxysilane (TEOS) (inorganic phase) in the presence of various molar ratios of coupling agents [γ-aminopropyltriethoxysilane (APTES) or 3-glycidoxypropyltrimethoxysilane (GPTMS)] through covalent bond interaction. The formation of a covalent bond between the organic and inorganic phases is confirmed by FT-IR. Thermal studies indicate that nanomaterials (CE-SiO₂) show a higher T_g and thermal degradation temperature when compared with neat CE. Morphological studies confirm the molecular level dispersion of silica and CE resin. From the contact angle measurement, the hybrid materials are seen to possess better hydrophobicity i.e. the contact angle value increases from 89°and 57°to 108°and 78°for water and diiodomethane as a probe liquid respectively, also surface free energy reduced from 32.8 to 19.00 mJ m^-2. These materials are expected to find wide application in the field of microelectronics and optoelectronics.