Preparation of Laser‐Induced Graphene Fabric from Silk and Its Application Examples for Flexible Sensor

Abstract

Laser‐induced graphene (LIG) with original macroscopic fabric structure, flexible characteristic, and minimum 40 Ω sq−1 sheet resistance is prepared by a two‐step method of heat treatment and laser direct writing (LDW) from a low‐cost and environmentally friendly silk fabric. The method can quickly control the electrical conductivity and mechanical properties of the product during processing. Laser parameters are adjusted by experiment to obtain an optimal about 40 Ω sq−1 sheet resistance. Finite element analysis (FEA) coupled with an experimental method is used to explain the relationship between processing, structure, and performance. Graphene can be detected on the upper and lower surface fibers of the thinner precursors under proper processing condition. The electrical conductivity of the product is influenced by material conversion and structural integrity caused by input laser energy, so it can be easily changed by adjusting laser processing parameters. The good performance of the product is related to uniform and sufficient but not excessive temperature field distribution. Moreover, the LIG fabric is also used in flexible sensors, for example, which have enough static and dynamic properties to be a wearable device.

Laser-Induced Graphene Based Flexible Electronic Devices

“…Additionally, the LIG has also been successfully realized on multiple natural and synthetic materials. As shown in Figure 1 , diverse substrates such as plants (i.e., woods, leaves, potato skins and coconut shells) [ 22 , 23 , 24 ], fabrics (i.e., Kevlar and silk) [ 24 , 25 , 26 , 27 ], papers (i.e., printing paper and PI paper) [ 28 , 29 , 30 ], and polymers (i.e., polyethylene terephthalate and phenolic resin) are transformed into graphene directly by laser irradiation [ 17 , 27 , 31 , 32 , 33 , 34 ]. The exceptional design ability in the electrical performances and the wide selection of carbon precursors demonstrate the potential of LIG in the fields such as flexible, large-scale, and biodegradable electronics.…”

“…Meanwhile, the conductivity, electrochemical performance [24,27,35,36], biocompatibility [37,38], and hydrophobicity [39][40][41] of LIG also have been systematically studied. A variety of LIG devices have been developed, including sensors [14][15][16][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42], supercapacitors [17,[43][44][45][46][47][48][49][50][51][52][53][54][55], nanogenerators [54][55][56][57][58]…”

“…The detected anisotropy is due to the specific orientation of the graphene-containing formations relative to the PI/LIG interface during the LIG formation. Furthermore, a variety of natural and synthetic materials, ranging from plants [ 22 , 23 , 24 ], textiles [ 24 , 25 , 26 , 27 ], papers [ 28 , 29 , 30 ] to other organic films [ 17 , 27 , 31 , 32 , 33 , 34 ], are experimentally demonstrated in serving as the carbon source to form LIG. Meanwhile, the conductivity, electrochemical performance [ 24 , 27 , 35 , 36 ], biocompatibility [ 37 , 38 ], and hydrophobicity [ 39 , 40 , 41 ] of LIG also have been systematically studied.…”

“…Meanwhile, the conductivity, electrochemical performance [ 24 , 27 , 35 , 36 ], biocompatibility [ 37 , 38 ], and hydrophobicity [ 39 , 40 , 41 ] of LIG also have been systematically studied. A variety of LIG devices have been developed, including sensors [ 14 , 15 , 16 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 ], supercapacitors [ 17 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 ], nanogenerators [ 54 , 55 , 56 , 57 , 58 , 59 , 60 , …”

Laser Synthesized Graphene and Its Applications

“…The same multi-pass approach was later proposed by the same group to obtain LIG from an acrylate-based positive photoresist [47]. A twostep approach was also proposed by Li et al [48] starting from silk fabric, as they first heated the material to 350 • C and then exposed the same to a laser scribing process to obtain LIG, as witnessed by Raman spectroscopy. Because lignin is a common industrial byproduct, Mahmood et al demonstrated the direct conversion of such material to graphene using laser writing [49].…”