Tailoring the supramolecular interaction of ionic liquids for high-sensitivity temperature monitoring under high pressure

Abstract

Temperature monitoring with high-pressure resistance, precision, and sensitivity is crucial for temperature measurement in complex environments. Traditional temperature sensors are limited by the sensitivities and cannot meet the requirements for temperature sensing under high-pressure conditions. Here, we propose a straightforward method to modulate supramolecular interactions within ionic liquids by doping them with metal salts, thus achieving enhanced temperature sensitivity. Iron-ion doping in 1-butyl-3-methylimidazolium dicyanamide ([BMIm][N(CN)₂]) led to exceptional sensitivity (>20%/°C) and detection of minute temperature differences (0.01 °C). Besides, polyurethane swollen by ionic liquids successfully detected temperature changes under a high pressure of 2000 N. Importantly, the approach allows studying structure–property relationships and demonstrates the potential of ionic liquids in high-pressure temperature monitoring, catering to the temperature monitoring needs in various complex environments.