Gels are comprised of polymer networks swelled by some interstitial solvent. They are under wide investigation by material scientists and engineers for their broad applicability in fields ranging from adhesives to tissue engineering. Gels’ mechanical properties greatly influence their efficacy in such applications and are largely dictated by their underlying microstructures and constituent-scale properties. Yet predictively mapping the local-to-global property functions of gels remains difficult due - in part - to the complexity introduced by solute-solvent interactions. We here introduce a novel, discrete mesoscale modeling method that preserves local solute concentration-dependent gradients in osmotic pressure through the Flory-Huggins mixing parameter, $\chi$. The iteration of the model used here replicates gels fabricated from telechelically crosslinked star-shaped polymers and intakes $\chi$, macromer molecular weight ($M_{\mathit{w}}$), crosslink functionality ($f$), and as-prepared solute concentration (${\varphi }^{*}$) as its inputs, all of which are analogues to the control parameters of experimentalists. Here we demonstrate how this method captures solvent-dependent homogenization ($\chi \le 0.5$) or phase separation ($\chi >0.5$) of polymer suspensions in the absence of phenomenological pairwise potentials. We then demonstrate its accurate, ab initio prediction of gel topology, isotropic swelling mechanics, and uniaxial tensile stress for a 10k tetra-PEG gel. Finally, we use the model to predict trends in the mechanical response and failure of multi-functional PEG-based gels over a range of $M_{\mathit{w}}$ and $f$, while investigating said trends’ micromechanical origins. The model predicts that increased crosslink functionality results in higher initial chain stretch (as measured at the equilibrated swollen state) for gels of the same underlying chain length, which improves modulus and failure stress but decreases failure strain and toughness.

凝胶由被一些间隙溶剂膨胀的聚合物网络组成。材料科学家和工程师正在广泛研究它们，因为它们在从粘合剂到组织工程等领域的广泛适用性。凝胶的机械性能极大地影响了它们在此类应用中的功效，并且很大程度上取决于它们的潜在微观结构和成分尺度性能。然而，由于溶质-溶剂相互作用引入的复杂性，预测性地映射凝胶的局部到全局特性函数仍然很困难。我们在这里介绍了一种新颖的离散中尺度建模方法，该方法通过 Flory-Huggins 混合参数保留渗透压中局部溶质浓度依赖性梯度，$\chi$. 这里使用的模型的迭代复制了由遥爪交联的星形聚合物和摄入量制成的凝胶$\chi$, 大分子单体分子量 (${米}_{\mathit{w}}$), 交联功能 ($F$) 和制备的溶质浓度 (${\phi }^{*}$) 作为其输入，所有这些都类似于实验者的控制参数。在这里，我们演示了该方法如何捕获溶剂依赖性均质化（$\chi \le 0.5$) 或相分离 ($\chi >0.5$) 在没有唯象成对势的情况下的聚合物悬浮液。然后，我们展示了其对 10k 四聚乙二醇凝胶的凝胶拓扑结构、各向同性膨胀力学和单轴拉伸应力的准确从头预测。最后，我们使用该模型预测多功能 PEG 基凝胶在一系列范围内的机械响应和失效趋势。${米}_{\mathit{w}}$和$F$，同时调查上述趋势的微机械起源。该模型预测，对于具有相同基础链长的凝胶，增加的交联功能会导致更高的初始链拉伸（在平衡溶胀状态下测量），这会提高模量和失效应力，但会降低失效应变和韧性。