Abstract
Addressing the loss of substrate conductivity after enduring numerous bending stands as a significant challenge for flexible electronics. The primary cause of reduced electrical conductivity in flexible polymer matrices is disorganization of conducting channels by mechanical stress generated during repeated stretching cycles. In this feature article, we extensively reviewed the strategies adopted to control structure formation of conducting networks by optimizing filler and matrix interactions at length scale. Studies, including our recent experiments, indicate that fractal formation of filler assemblies in polymer matrix determines the stability of conducting channels. A wide range of polymers and conducting fillers with different geometries and functional attributes have been analyzed to highlight the intra and intermolecular reinforcing effects to address the shear stresses originating in flexible substrates. Understanding non-bonded interactions between polymers and fillers may lead to the development of desired formulation of conducting inks to print on flexible surfaces for next-generation wearable electronics.
Acknowledgments
One of the authors (DR) acknowledges the German Academic Exchange Programme (DAAD), Germany, for providing the fellowship for a research stay at the Leibniz Institute for New Materials (INM), where some of the initial work on flexible conductor films has been carried out. Dr. Roy extends deep appreciation to Professor Eduard Artz and Professor Tobias Kraus for their mentorship in developing long-term stretchable conductors for flexible electronics. The authors acknowledge their national and international academic collaborators for the invaluable inputs and suggestions they provided from time to time. The authors also express their sincere gratitude to Dr. Kingsuk Mukhopadhyay and their colleagues at Defence Materials and Stores Research and Development Establishment (DMSRDE) for their unwavering encouragement and exceptional support of nanomaterials research at DMSRDE, Kanpur, India. The authors thank the Director, DMSRDE, for permission to publish this manuscript.
Disclosure statement
No potential conflict of interest was reported by the authors.