Stretchable patterned graphene gas sensor driven by integrated micro-supercapacitor array

We report on the fabrication of a stretchable patterned graphene gas sensor driven by integrated micro-supercapacitor (MSC) array on the same deformable substrate. The integrated MSCs consist of polyaniline-wrapped multi-walled carbon nanotube electrodes and an ionogel electrolyte of poly(ethylene glycol)diacrylate and 1-ethyl-3-methylimidazoliumbis (trifluoro-methylsulfonyl) imide. The deformable soft Ecoflex substrate was designed to suppress the applied strain on the gas sensor and MSCs via insertion of stiff platforms of SU-8 underneath and serpentine electrical interconnections of polymer-encapsulated long and narrow Au thin film. The fabricated MSC array demonstrated stable electrochemical performance under a uniaxial strain of 50% and a biaxial strain of 40%, maintaining its initial characteristics even after 1000 cycles of repetitive uniaxial and biaxial stretching. Furthermore, the patterned-graphene sensor detected NO2 gas for longer than 50 min via integration with MSCs using the serpentine interconnections even under uniaxial stretching by 50%. This work suggests fundamental progress towards the development of stretchable environmental sensor system which can be driven by integrated energy storage devices without external long wire connections to power source. (C) 2015 Elsevier Ltd. All rights reserved.