Development and Characterization of a DC-Driven Thermal Oscillator Using Acrylate-Based Composites

Abstract

This paper presents the design, fabrication, and characterization of a thermal oscillator driven by fixed DC voltages. The proposed device consists of a miniaturized ultra-sensitive temperature sensor and a microheater. The temperature sensor was fabricated by depositing acrylate-based temperature sensing material with a positive temperature coefficient (PTC) effect on an interdigital electrode pair, and this was the key component that enabled oscillations by periodically switching the microheater on and off. The acrylate-based material, which was prepared by dispersing an acrylate copolymer with graphite particles, exhibits an order-of-magnitude variation in resistivity over a temperature change of a few degrees. The transient behavior of the fabricated device was measured, and the effects on different driving conditions with active cooling were measured and discussed. In addition, the measurement results also show that the temperature drift is not obvious in long-term testing, which indicates that the acrylate composite is quite reliable during repeated phase transition.