Graphene-Based Composite Protective Coating for Twisted Strings and Its Experimental Evaluation

Abstract

Twisted string actuators (TSAs) have found extensive use in various areas of engineering and in consumer products due to their mechanical simplicity and flexibility. Despite huge future potential of TSAs, reliability of the strings operating in stringent conditions has remained a significant concern. The increased string wear due to friction between the fibers and strands is the main reason of comparatively short lifetime of the strings in TSAs. However, very limited research has been done in this area, thus methods to extend the string lifetime remains an open question. Similarly, despite intensive research efforts on graphene over the past decade, its potential as reinforcement in coating material remains comparatively unexplored. In this paper, we report the preparation and implementation of a unique graphene-based composite coating for TSAs. The graphene sample was analyzed by both structural and chemical characterization procedures before the preparation of the coating material. The coated strings were also analyzed thoroughly using both spectroscopic and microscopic techniques. The experimental studies demonstrated that we could increase lifetime of the newly coated strings by approximately 100 $\%$ in comparison with the coated strings procured commercially. The development of this new graphene-based coating material may usher a favorable outlook in the application of TSAs in future.