Salahshoor Hossein, Rahbar Nima
School of Aerospace Engineering, Georgia Institute of Technology, Atlanta, GA, United States.
Department of Civil and Environmental Engineering, Worcester Polytechnic Institute, Worcester, MA, United States.
J Mech Behav Biomed Mater. 2014 Sep;37:299-306. doi: 10.1016/j.jmbbm.2014.05.028. Epub 2014 Jun 5.
In this paper, molecular dynamic simulation was used to study the effect of water on the equilibrated structure and mechanical properties of cross-linked hydrogel at multiple scales. The hydrogel consisted of Polyethylene glycol diglycidyl ether (PEGDGE) as epoxy and the Jeffamine, poly-oxy-alkylene-amines, as curing agent. The results for systems with various water contents indicated that the cross-links were more hydrophilic within the hydrogel structure. Effects of cross-linking on the transport properties were also investigated by computing diffusion coefficients of water molecules. A new Coarse-Grained (CG) scheme for hydrogels is proposed, and validated by comparing the transport properties with the all-atom method, demonstrating the capability of the model to capture the correct dynamic evolution of the system. The all-atom model of the hydrogel was mapped to the CG model using the MARTINI force field. This method resulted in a more realistic representation of the stiffness of the system, compared to the previous experimental studies in the literature. The variation of the stiffness of the hydrogel as a function of the water content showed that 40% water content is the optimal value for mechanical performance of the hydrogel.
在本文中，采用分子动力学模拟在多个尺度上研究了水对交联水凝胶平衡结构和力学性能的影响。该水凝胶由聚乙二醇二缩水甘油醚（PEGDGE）作为环氧树脂和聚氧化烯胺Jeffamine作为固化剂组成。不同含水量体系的结果表明，水凝胶结构内的交联键更具亲水性。还通过计算水分子的扩散系数研究了交联对传输性能的影响。提出了一种新的水凝胶粗粒化（CG）方案，并通过将传输性能与全原子方法进行比较进行了验证，证明了该模型能够捕捉系统正确的动态演化。使用MARTINI力场将水凝胶的全原子模型映射到CG模型。与文献中先前的实验研究相比，该方法对系统刚度的表示更符合实际。水凝胶刚度随含水量的变化表明，40%的含水量是水凝胶力学性能的最佳值。
