The interfacial interactions and their effects on electrical properties are reported for thermally grown SiO2-Parylene-C laminar composites. The segmental chain mobility of the interfacial Parylene-C was found to be enhanced in the composites. TSDC (thermally stimulated depolarization current) measurements showed the presence of dipolar interfacial energy states in these laminar composites. Functionalization of the oxide surface with 3-aminopropyltriethoxysilane (APTES) created dipolar energy states with larger activation energy at the interface between Parylene-C and SiO2. In addition to the modification of interfacial states, incorporation of APTES interfacial layer also increased polarizability (real part of permittivity) and reduced the quasi-DC conductivity of laminar composites. The systematic changes in interfacial characteristics with thickness of APTES layer were explained based on structural orientation and cross linking of silane molecules. (c) 2009 Elsevier Inc. All rights reserved.