Contact-probe methods have been developed to measure thermal transport properties of solid materials. Although they have an advantage of being used for non-destructive in-situ measurement, it has a substantial problem that the measured results are influenced by thermal contact between the probe and the specimen. To overcome this problem, we proposed a new technique using a gel to eliminate the contact resistance. A unique feature of the method is that a thin film heater is fabricated on a substrate at the bottom of a shallow cavity, which provides a gel layer of the thickness that is almost the same as the cavity depth. When we use this sensor, we press it against a surface of a specimen with a gel in between. We named it "stamp sensor" from its supposed use and appearance. The thermal conductivity and the thermal diffusivity of a specimen and the thickness of the gel layer are determined simultaneously by comparing the measured temperature rise of the sensor with that obtained by numerical analysis. The objective of the present paper is to demonstrate the feasibility of the method by virtual experiments. The process to determine the thermal conductivity and the thermal diffusivity was examined using simulated experimental data that have been generated from the temperature rise of the sensor obtained by numerical analyses with given artificial scattering. Effects of the scattering of the data, the heating power and the heating time on the measurement error were also discussed.

A contact method has been proposed for measuring thermal transport properties of solids including soft materials. The method has an advantage of potential utilization for in-situ measurement without preparing a sample specimen. A unique feature of the method is to prepare a shallow cavity around a film sensor for a layer of a gel that is used to eliminate the thermal contact resistance between the sensor and the sample. A prototype sensor, 3 mm in diameter, was fabricated on the surface of 0.16-mm thick glass substrate, and used with a 50-m thick silicon rubber sheet as a spacer for the gel. The transient temperature rise of the sensor was determined from the electrical resistance after heating the sensor at a constant current. The thermal conductivity and the thermal diffusivity of a sample as well as the thickness of the gel layer were then determined from an iteratively obtained theoretical temperature rise that agreed with the measured temperature rise. The results obtained the experiments with four different materials indicated that the thermal conductivity could be determined within 10% errors. The present study therefore demonstrates feasibility of the method, while improvement is still needed to reduce the error particularly in the thermal diffusivity.