Preparation of novel stretchable conductors for smart fabric applications.
Current Flextronics systems available commercially are based on thermo-plastics like polyimide, can only bear strains of a few % and hence can flex but not stretch. To have a truly stretchable electronic circuit would bring many innovations in a range of technologies including bio-implantable devices, bio-sensing, solar cells, smart clothes and embedded systems.
A current and relatively efficient method to prepare stretchable conductors is to deposit a metal film on an elastomeric substrate (ie gold/PDMS). The challenge, nonetheless is that these metal films are laced with cracks. This results from the large thermo-mechanical dissimilarities between the two materials and the ensuing strains, either built-in from the post metal deposition cooling or from applied stresses.
Uni-axiale pre-stretching has been used for many years now to produce periodic microstructures which in effect release the compressive stress due to thermal mismatch on cooling. The idea is simply that until the applied stress reaches the pre-stress, the film bends but does not stretch, hence is unlikely to experience significant cracking. In NIBEC, we have generalized this concept to bi-axial stress release using a photolithographic patterning technique [1] and an amorphous carbon interlayer [2]. The present investigation is aimed at using random patterns to produce bi-axial strain relief which can be effective in any direction, hence widening the usage of such materials to truly bi-axial applications. The work is of a pluri-disciplinary nature and provides opportunities for inspired students with background in physics, material science, biomedical, or mechanical engineering or chemistry
[1] Tuinea-Bobe, C, Lemoine, P, Manzoor, MU, Tweedie, M, D'Sa, R, Wallace, E and Gehin, C (2011) Photolithographic structuring of stretchable conductors and sub-kPa pressure sensors. Journal of Micromechanics and Microengineering, 21 .
[2] Manzoor, MU, Tuinea-Bobe, CL, McKavanagh, F, Byrne, CP, Dixon, D, Maguire, PD and Lemoine, P (2011) Amorphous carbon interlayers for gold on elastomer stretchable conductors. Journal of Phys D, Applied Physics , 44 (24). 245301-9pp.
Personnel Involved
First Supervisor: Lemoine, P Dr
Second Supervisor: Dixon, D Dr
Collaboration: This project does not involve collaboration with another establishment