Thermal conductivity of porous silica films using modified polydimethylsiloxane and polyethyleneglycol as templates by sol–gel process

This paper reports the heat-resistant property of porous silica films synthesized using the sol–gel method. In the sol–gel system, a mixture solvent was adopted and side-chain polyether modified polydimethylsiloxane and polyethyleneglycol were introduced as the template and viscosity adjusting agent, respectively. Differential thermal analysis/thermogravimetric analysis, Fourier transform infrared spectroscopy, field emitted scanning electron microscope, and high-resolution transmission electron microscopy were employed to characterize the samples. Thermal conductivity measured by the 3ω method as functions of porosity, thickness, and annealing temperature was discussed in detail.

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► Side-chain polyether modified PDMS and PEG are used to prepare porous silica films.
► Large area porous silica film with crack-free is easy to be prepared.
► Thermal conductivity as a function of porosity is in agreement with the PWSM model.
► Thermal conductivity is dependent of film thickness.
► Thermal conductivity is also dependent of annealing temperature.