Computational study of the water-driven graphene wrinkle life-cycle towards applications in flexible electronics

Abstract

The ubiquitous presence of wrinkles in two-dimensional materials alters their properties significantly. It is observed that during the growth process of graphene, water molecules, sourced from ambient humidity or transferred method used, can get diffused in between graphene and the substrate. The water diffusion causes/assists wrinkle formation in graphene, which influences its properties. The diffused water eventually dries, altering the geometrical parameters and properties of wrinkled graphene nanoribbons. Our study reveals that the initially distributed wrinkles tend to coalesce to form a localized wrinkle whose configuration depends on the initial wrinkle geometry and the quantity of the diffused water. The movement of the localized wrinkle is categorized into three modes—bending, buckling, and sliding. The sliding mode is characterized in terms of velocity as a function of diffused water quantity. Direct bandgap increases linearly with the initial angle except the highest angle considered (21°), which can be attributed to the electron tunneling effect observed in the orbital analysis. The system becomes stable with an increase in the initial angle of wrinkle as observed from the potential energy plots extracted from MD trajectories and confirmed with the DOS plot. The maximum stress generated is less than the plastic limit of the graphene.

Surface Wrinkling for Flexible and Stretchable Sensors

“…When compared to microdome structures without wrinkles, the surface wrinkles of the regular dome structures changed the contact area linearly under the applied pressure, allowing the flexible pressure sensor to perform with linearity and higher sensitivity. Kashyap et al [87] generated wrinkles on the graphene surface using water evaporation (Figure 11b). The wrinkles could be produced by the diffused water and subsequently its evaporation during graphene growth in high humidity conditions and could be easily controlled by modifying the humidity amount.…”

“…Other methods for developing wrinkle-based flexible or stretchable sensors have also been reported (Figure 11). [10,[87][88][89] Linearly and highly sensitive pressure sensors with hierarchical structures comprising surface wrinkles and microdome structures were achieved (Figure 11a). [10] In this report, wrinkled morphology was formed by thermal oxidation of the copper foil, followed by graphene growth on the surface and molding with PDMS.…”

“…Kashyap et al. [ 87 ] generated wrinkles on the graphene surface using water evaporation (Figure 11b). The wrinkles could be produced by the diffused water and subsequently its evaporation during graphene growth in high humidity conditions and could be easily controlled by modifying the humidity amount.…”

“…Bottom: Atomic force microscopy images of the monolayer graphene with wrinkled geometry (Reproduced with permission. [ 87 ] Copyright 2020, Nature Publishing Group). c) Left: Schematic diagram of the wrinkling phenomenon by electrospinning.…”

Drug repurposing for SARS-CoV-2: a high-throughput molecular docking, molecular dynamics, machine learning, and DFT study

“…But our model is tweaked to assign zero weights if the pairwise inverse distance crosses a threshold. That is equivalent to assigning a cutoff value for force-field-based classical molecular dynamics approaches [ 30 – 33 ].…”