Fine control of carbon-polyelectrolyte thin film sensors sensitivity for human motion monitoring

Abstract

Carbon nanomaterials have emerged as highly promising nanomaterials for recent thirty years. There have been numerous researches regarding potential applications of carbon nanomaterials due to their outstanding properties which originate from the network of sp2-hybridized carbon atoms. In this regard, it is also reported that a variety of functional composites or hybrid materials with carbon nanomaterials result in novel applications as well as synergistic enhancements in target properties. In this study, multi-functional polymer/graphene nanoplatelet multilayer composite films were fabricated by layer-by-layer assembly. Graphene nanoplatelets (GNPs), two-dimensional carbon nanomaterials provide not only excellent electrical conductivity but barrier property for gas molecules. Layer-by-layer assembly is a simple, inexpensive bottom-up techniques for multilayer film deposition with easy control of inner structures. In this study, transparent conductor for next generation flexible electronics was considered as a potential application of layer-by-layer assembled polymer/GNP multilayer composites films. GNP coating on thin polymer substrates was expected to be applicable to flexible display applications, while metal oxides such as indium tin oxide have a limitation due to its mechanical fragility. Thus, electrically conductive layer-by-layer assembled GNP films which shows gas barrier property as well as mechanical flexibility could be fabricated with low material and processing cost. Though thermal annealing and acid treatment on GNP films effectively lowered the sheet resistance of the films, their transmittance and sheet resistance still need to improve further to be used as transparent conductors for flexible display applications. Meanwhile, further efforts must be focused on the possibility of other applications.