Polydiacetylene-Crosslinked Oligosiloxanes for Dual-Mode Temperature Sensing

Polydiacetylenes (PDAs) are versatile smart materials due to their unique optoelectronic properties and sensitivity to environmental changes such as temperature, pH, and pressure, leading to distinct color transitions. Despite advantageous features, the limited solubility and challenging processing of PDAs often restrict their application in sensor manufacturing. Addressing the limitations of PDAs, this work combines PDAs with oligosiloxanes to create a material exhibiting good solubility in common organic solvents, facilitating the formation of thin films through solution deposition. A meticulous characterization strategy is used, including Raman spectroscopy, optical spectroscopy, and differential scanning calorimetry, to explore the thermochromic and electronic properties of the new crosslinked materials for the fabrication of optical-electronic temperature sensors. The synthesized material displayed reversible thermochromism from 25 to 47 °C and a nonreversible transition beyond this temperature range. Dual-mode capacitive temperature sensors fabricated from the new materials exhibited sensitivity (0.1 pF/°C) in the 25–80 °C range. The hybrid sensing mechanism developed enhances accuracy and reliability by monitoring temperature changes through both colorimetric shifts and capacitance variation. The development of new PDA-crosslinked oligosiloxane not only marks an advancement in smart material technology but also opens new possibilities for diverse sensor applications.