Wet-to-Dry Hybrid Spinning of Graphene Fiber Inspired by Spider Silk Production Mechanisms

Abstract

This study describes a graphene oxide (GO) fiber spinning method that produces a nearly 100% yield for converting a GO suspension into fibers. The fiber formation method is inspired by the spider silk spinning strategy. The dissolved silk protein, spidroin (wet state), is extruded and shear-thinned through a posterior spinneret, exposing the silk to a dry state for curing. The wet-to-dry conversion in a spider spinneret enables nearly all the fiber precursor, spidroin, to be fabricated into a silk fiber with no loss of protein. Inspired by the process, a "wet-to-dry" hybrid spinning of GO is developed in which nearly all GOs are converted into fiber. At the liquid-liquid interface of two droplets containing GO and polyethyleneimine, the two oppositely charged components bind to each other in the wet state. Subsequently, one component touches and pulls the interfacial mixing point of the two droplets, forming a vertical, thin liquid column in which GO complexes experience shear force and directionally align into a thin fiber. Compared to existing wet-spinning methods, this wet-to-dry method is highly energy efficient in terms of the simple procedure, lack of waste chemicals, and nearly 100% conversion of GO precursors.