Department of Materials Science and Engineering, İzmir Katip Çelebi University, 35620 İzmir, Turkey.
Department of Aerogels and Aerogel Composites, Institute of Materials Research, German Aerospace Center, Linder Höhe, 51147 Cologne, Germany.
Soft Matter. 2021 Jun 2;17(21):5278-5283. doi: 10.1039/d1sm00430a.
Hydration induces significant structural rearrangements in biopolymer aerogels, resulting in a completely different mechanical behaviour compared to the one in the dry state. A network decomposition concept was earlier introduced to account for these changes, wherein the material network was decomposed into an open-porous aerogel one and a hydrogel-like one. Recent experimental evidences have supported this idea of the formation of a hydrogel-like network. Using these observations as a basis, in this paper, we present a micromechanical model describing the effect of hydration on the structural and mechanical properties of aerogels. The aerogel network is modelled based on the mechanics of their pore-walls, while the hydrogel-like network is modelled based on the statistical mechanics of their polymer chains by means of the Arruda-Boyce eight-chain model. The influence of diverse structural and material parameters on the mechanical behaviour is investigated. The effect of different degrees of wetting, from a pure aerogel to a pure hydrogel-like state, is captured by the model. The results are shown to be in good agreement with available experimental data.
水合作用会引起生物聚合物气凝胶的显著结构重排，从而导致其机械性能与干燥状态下完全不同。先前曾引入网络分解概念来解释这些变化，其中将材料网络分解为开放多孔气凝胶网络和类水凝胶网络。最近的实验证据支持了形成类水凝胶网络的这一观点。在此基础上，本文提出了一个描述水合作用对气凝胶结构和力学性能影响的细观力学模型。气凝胶网络基于其孔壁的力学进行建模，而类水凝胶网络则基于聚合物链的统计力学，通过阿卢达-博伊斯八链模型进行建模。研究了不同结构和材料参数对力学行为的影响。该模型捕捉到了从纯气凝胶到纯类水凝胶状态的不同润湿程度的影响。结果与现有实验数据吻合较好。
