A material has been discovered that exhibits an electrical response to temperature changes in the lab.
The component responsible for this sensitivity to temperature is pectin, the long-chain molecule present in plant cell walls.
Chiara Daraio, professor of mechanical engineering and applied physics in the Division of Engineering and Applied Science at Caltech, said: “Pectin is widely used in the food industry as a jellifying agent. It’s what you use to make jam. So it’s easy to obtain and also very cheap.”
Daraio and her research team made the discovery while making synthetic woods in a petri dish. As a result the team switched its attention to pectin and created an ultra-thin, transparent flexible film of pectin and water.
The weakly bonded double-strand structure of pectin molecules contains calcium ions. An increase in temperature breaks the bonds and the double strands ‘unzip, so releasing the positively charged calcium ions.
Currently this ‘skin’ is capable of detecting changes across a range of temperatures between five and 50 degrees Celsius (approximately 41 to 158 degrees Fahrenheit).
Daraio’s team would like to boost that up to 90 degrees Celsius (194 degrees Fahrenheit), making the material appropriate for industrial applications, such as thermal sensors in consumer electronics or robotic skins to augment human-robot interactions.