Understanding Large Temperature Responsivity of Plant-Inspired Polymer

The electrical resistance of higher plants has been reported to be exponentially correlated with the ambient temperature. Their large temperature sensitivity is attributed to the pectin-calcium-ion complex in the plant cell wall. Our group has fabricated flexible transparent films, containing pectin and calcium chloride, and measured two-order of magnitude higher response than the best flexible temperature sensing films, between 0 to 45 Celsius. The potential application of this material is broad, ranging from temperature-sensing artificial skin to micro-bolometers. However, the physics of this high temperature sensitivity is still unknown. In order to understand the molecular mechanism of this behavior and to optimize its properties, we performed spectroscopic experiments and computational modeling on various pectin-based systems. Results explain how ion-pectin interactions change with temperature, and shed some light on the mechanisms behind the record-high temperature responsivity.