▎ 摘　　要

The popularity of graphene origami eyed for applications in electronics, energy harvesting, molecular storage and membrane development has been on the rise for the last few years. Experimental studies have demonstrated that graphene grafted with thermo-sensitive polymers such as poly(N-iso-propylacrylamide) (PNIPAM) folds into three-dimensional (3D) structures in response to change in the surrounding temperature. This process, attributed to the coil-to-globule transition of PNIPAM, is however, poorly understood, making the creation and control of these self-folded 3D structures difficult. Here, for the first time, we employ coarse-grained (CG) molecular dynamics (MD) simulations to develop an accurate molecular-level mechanism for the self-folding of PNIPAM-grafted graphene in presence of an explicit solvent. Our analyses of contacts, energetics and structure of PNIPAM-solvent interface indicate that the process is actually initiated by the weakening of PNIPAM-water interactions at higher temperatures, resulting in strong hydrophobic graphene-PNIPAM interactions. By further varying system parameters like graphene width and polymer coverage, we also provide energy criteria for graphenefolding. The molecular-level insights obtained through this study can be essential for controlling and tuning the process of graphene self-folding via temperature control. (c) 2021 Elsevier Ltd. All rights reserved.