Mechanics of cellulose nanopaper using a scalable coarse-grained modeling scheme
Mechanics of cellulose nanopaper using a scalable coarse-grained modeling scheme
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DOI：
10.1007/s10570-021-03740-x
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发表时间：
2021-03-02
期刊：
影响因子：
5.7
通讯作者：
Li, Teng
中科院分区：
文献类型：
--
作者：
Ray, Upamanyu;Pang, Zhenqian;Li, Teng
纤维素是一种大量存在且可持续的生物聚合物，其固有机械性能优于许多高性能结构材料。基于纤维素的材料所具有的优异机械性能本质上取决于其从纤维素分子链到大规模纤维的自下而上的分级材料结构。然而，对于涉及长度尺度效应的力学研究，在实验样本尺寸下对这类材料进行全原子模拟在计算上是难以实现的。为了应对这一挑战，在此我们开发了一种自下而上、可扩展的纤维素材料粗粒化（CG）建模方案，以便从分子链到纳米纤维，再到微纤维尺度，深入了解不同长度尺度的纤维素构建单元之间的相互作用，从而研究基于纤维素的材料的变形和失效机制。在研究了纤维素纤维在剪切和拉伸等不同载荷下的响应之后，将这种CG方案应用于研究纤维素纳米纸在拉伸下的变形过程，从而揭示了原子模拟无法实现的纳米级失效机制。此外，CG模型还预测了纳米纸相对于不同纤维长度的强度和刚度。鉴于其可扩展性，这种CG建模方案可以很容易地适用于从分子尺度深入研究其他基于纤维素的材料的力学行为，因此有望促进基于纤维素的高性能材料的设计。
Cellulose, the abundantly available and sustainable biopolymer, exhibits intrinsic mechanical properties superior to many high-performance structural materials. The exceptional mechanical properties of cellulose-based materials inherently hinge upon their bottom-up hierarchical material structure starting from cellulose molecular chains to large scale fibers. However, fully atomistic simulation of such materials at experimental sample dimension becomes computationally prohibitive for the exploration of mechanics involving length scale effects. To address this challenge, here we develop a bottom-up, scalable coarse-grained (CG) modeling scheme of cellulose materials to study the deformation and failure mechanism of cellulose-based materials with insight of the interplay among cellulose building blocks at different length scales, starting from molecular chain, to nanofiber, and finally to microfiber scales. After studying the response of cellulose fibers under different loadings such as shearing and opening, this CG scheme is applied to study the deformation process of a cellulose nanopaper under tension, thus revealing the nanoscale failure mechanism otherwise impossible by atomistic simulations. In addition, the CG model also predicts the strength and stiffness of the nanopaper with respect to varying fiber lengths. Given its scalable nature, such a CG modeling scheme can be readily adapted to study the mechanical behaviors of other cellulose-based materials with mechanistic insight from molecular scale, and thus holds promise to foster the design of cellulose-based high-performance materials.