Dielectric behavior of organically modified siloxane melting gels

• Published in: Journal of non-crystalline solids Vol. 358; no. 24; pp. 3501 - 3504
• Main Authors: Gambino, Louis, Jitianu, Andrei, Klein, Lisa C.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Oxford Elsevier B.V 15-12-2012; Elsevier
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Dielectric constant; Dielectric properties of solids and liquids; Dielectric strength; Dielectrics, piezoelectrics, and ferroelectrics and their properties; Equations of state, phase equilibria, and phase transitions; Exact sciences and technology; Low-k dielectrics; Materials science; Materials synthesis; materials processing; Melting gels; Optical constants: refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of bulk materials and thin films; Organic–inorganic gels; Permittivity (dielectric function); Physics; Solid-liquid transitions; Specific phase transitions; Low-k dielectrics; Dielectric constant; Dielectric strength; Organic–inorganic gels; Melting gels; Frequency dependence; Organic-inorganic gels; Melting; Refractive index; Permittivity; Sol-gel process; Low k dielectric; Electric strength
• ISSN: 0022-3093; 1873-4812
• DOI: 10.1016/j.jnoncrysol.2012.01.002

Hybrid melting gels were prepared by a sol–gel process, starting with a mono-substituted alkoxysilane and a di-substituted alkoxysilane, methyltriethoxysilane (MTES) together with dimethyldiethoxysilane (DMDES). Five gel compositions were prepared with concentrations between 50% MTES–50% DMDES and 75% MTES–25% DMDES (in mol%). The index of refraction was measured using a Becke line method. The index of refraction decreased slightly as the amount of mono-substituted alkoxysilane decreased. The dielectric constant was determined from impedance spectrometry that followed dielectric constant and dielectric loss as a function of frequency. The dielectric constant was lowest in the 50% MTES–50% DMDES composition at frequencies greater than 1kHz, around 3.3. Since direct SiC bonds are less polarizable than SiOSi, the di-substituted alkoxysilane component decreases the dielectric constant.
► Mono-substituted alkoxysilanes and di-substituted alkoxysilanes produce melting gels. ► Dielectric constants measured on melting gels show values as low as 3.3 at 1kHz. ► An increase in di-substituted alkoxysilane decreased the dielectric constant.