Low dielectric constant silica-containing cross-linked organic-inorganic materials based on fluorinated poly(arylene ether)s
Abstract
In this work, for the first time, we describe the design and synthesis of novel fluorinated poly(arylene ether)/silica cross-linked materials (FPAE/SiO1.5) through a sol-gel process by using the triethoxysilyl-containing fluorinated polyethers as precursors for both organic and inorganic networks formation. The polyether-based precursors with the sol-gel active species were synthesized via hydrosilylation reaction between triethoxysilane and the corresponding allyl-functionalized FPAE under Pt catalysis.
Herein, we present two approaches of hydrolysis triethoxysilane groups to silanol ones within sol-gel chemistry: (1) hydrolysis with air moisture and (2) hydrolysis of the ethoxysilyl groups at the interface between two liquids. The mechanical and thermal properties of the FPAE/SiO1.5 materials were studied depending on the structure of macromolecular chains and synthetic route.
Scanning electron and atomic force microscopies were employed to investigate the morphology of the resulting silica-containing cross-linked materials. The resulting FPAE/SiO1.5 films were flexible and tough with tensile strength above 25 MPa, and exhibited high thermal stability, having the initial decomposition temperature about 300 degrees C.
For more detailed explanation of the thermophysical behavior of the FPAE/SiO1.5 materials, the synthesis method of new silica-containing organic-inorganic system was developed by the direct hydrosilylation reaction between allyl-functionalized polyethers and 1,1,3,3-tetramethyldisiloxane. All films exhibited high hydrophobic properties (water contact angles above 102 degrees), low dielectric constants and losses at room temperature.
In particular, the FPAE/SiO1.5 film prepared from tetrafluorobenzene-based polyether showed the ultra-low dielectric constant of 1.86 at 10 kHz. This makes the obtained polymer FPAE/SiO1.5 materials attractive for microelectronics and many other emerging applications.