Strain sensor with low thermal conductivity concealing resin for enhanced detection sensitivity and improved spatial resolution

Abstract

An advanced thermoresistive strain sensor was proposed and realized with a concealing layer in this work, in which the heat transfer by conduction and convection for Joule heating-induced thermal energy were different from the existing sensor. Because the existing sensor was with a structure concealed by air and the proposed concealing layer in the advanced sensor was composed of polymeric materials, studies were made on the impacts generated by different concealing materials. Results indicated that conductions of heat transfer of solid spin-on glass and resin were that, although stronger than that of gaseous air, the heat transfer by convection in solid materials were negligible for enhanced performance. Results also indicated that the sensor with a solid concealing layer outperformed in detection sensitivity than the sensor without a concealing layer, and a low thermal conductivity solid concealing layer outperformed a high thermal conductivity solid concealing layer. On average, the detection sensitivity was enhanced by 46.32% and 58.57% for tension and compression in terms of background temperature-based gauge factor, respectively. Theoretical designs, numerical simulations, fabrications, analyses, and discussions were comprehensively provided in this work with additional case study on practical application of microscopic strain in a slightly deformed plastic substrate in a roll-to-roll manufacturing system as the proof-of-concept.