Engineering of Self-healing Adhesives and Polymeric Sensors with Stretchable Applications

Abstract

An ultra-fast self-healing adhesive (SHA) has been developed based on a reversible network of dynamic metal−ligand interactions which is strategically manipulated by activation energy control. The amorphous structure with a low glass transition temperature (Tg) induced by the formation of zinc-poly(vinyl alcohol) (PVA) complexes enables this polymer to be autonomously healed under ambient conditions without any intervention after mechanically damaged. The mechanical and electrical properties of the SHAs can be tuned by varying the metal/ligand ratio as well as an amount of water within materials. This dynamic coordination bond-mediated elastomer exhibits not only an excellent adhesion property to a variety of substrates but also a mechanically superior deformability compared to conventional elastomers being exploited for stretchable electronics. It is also demonstrated that novel stretchable ammonia vapor sensor based on polymer electrolytes can be prepared and this system is extensively investigated. The presented sensor, comprised of the plasticized PVA electrolyte with glycerol, exceeds the performance of conventional SWCNT-based ammonia sensors in terms of sensitivity, recovery time, and stretchability. This stretchable chemical sensor has the advantage of easy fabrication, low cost, convenient scale-up and reliable sensing performances. In addition to the high sensitivity and stretchability, a remarkable selectivity for discriminating ammonia from different chemicals including water has also been observed for this new sensor. From our knowledge so far, this thesis work is the first attempt to develop a stretchable ammonia vapor sensor based on polymer electrolytes. With new materials and mechanisms, our polymeric sensors are promising as commercially viable and alternative ammonia sensors in the field of robotics and wearable electronics.