University of Cambridge
Stretchability in an electronic system is its ability to negotiate mechanical deformations without letting them interfere with its electrical functionality. This is a novel and challenging demand on electronic device technology, which has, to date, mainly pushed for smaller scale fabrication and increased performance. When interfaced with the human body, the electronic system should ideally match the 3D shape and natural elasticity of the biological.
Today, electronic circuits are thousands of time stiffer than the human skin and have limited flexibility. My research aims at reducing the mechanical mismatch between hard, rigid electronic devices and soft, compliant biological tissues. To do so, I develop the technology for stretchable circuits, thin-film electronic circuitry prepared on rubbery substrates.
Over the last year, I have shown that it is possible to fabricate simple logic circuits on silicone rubber using organic semiconductor materials. The circuits on elastomer do not perform as fast as a silicon chip but well enough to interface arrays of sensors such as touch or pressure receptors. The characterisation of their mechanical robustness is the next step to validate.
When the electronic interface is to be implanted directly in the body, the involved artificial materials need to be biocompatible, i.e. non-toxic to cells and tissues and not affected by the biological environment. Various silicone elastomers have been evaluated in vitro to define whether or not they would trigger harmful response from cultured cells. We found that some photosensitive silicones do and therefore will not be used for future devices.
Future electronic systems will be soft and elastic. Their field of applications will reach everyone, either by enabling wearable electronic devices, providing cheap and disposable skin healing monitors, or offering alternatives to patients in need of active prosthesis.