Thermal diffusivities of commercial polyvinylidene fluoride films measured by laser induced carbon heat source method

摘要

A simple and effective method, laser induced carbon heat source (LICHS), for estimating the thermal diffusivity of P-films is discussed. The black carbon was used for the substrate since it does not change in surface irregularity because an epoxy adhesive was used for the contact between the polyvinylidene fluoride (PVDF) film and carbon substrate (C-substrate). The irradiated light that passed through the film without absorption reached the surface of the C-substrate. A heat source was formed there, and thermal wave (TW) propagated from it. TW reaching the film surface was converted to a sound wave (gas pressure wave). The pressure wave was detected and converted to voltage through a microphone. The TW propagating toward the boundary of the P-film and adhesive generates a heat source having the surface temperature of adhesive T_a there. The thermal diffusivity α_p values of commercial PVDF films are not constant.