AI 中文总结
本研究开发了层状硅酸盐黏土的MARTINI-3粗粒化力场，验证其稳健性，并揭示有机改性蒙脱土可增容TPS-PE共混物，将界面张力从45降至13.06 mN/m。
AI 中文摘要
层状硅酸盐黏土因其高各向异性和可调的表面极性而被广泛用于聚合物纳米复合材料中。它们在聚合物共混物中的分布和界面定位可用于调控聚合物-黏土纳米复合材料（PCNCs）的性能。黏土的粗粒化（CG）力场有助于PCNC开发中的分子模拟。在此，我们为具有不同表面极性的层状硅酸盐黏土开发了MARTINI-3参数，这是一种具有高化学特异性的CG力场。黏土官能团的初始相互作用由水合自由能确定，该自由能通过将Lifshitz理论应用于实验表面张力数据获得。这些参数利用热塑性淀粉（TPS）-黏土复合材料的全原子（AA）分子动力学（MD）模拟的结构、热力学和动力学性质进行了微调。未用于CG参数化的TPS组分的径向分布函数和二体过剩熵被准确估算，确立了参数的稳健性。我们研究了黏土表面极性对聚合物链段动力学和结构-性能关系的影响。随后，使用CG参数通过大时间和长度尺度的MD模拟研究了十二烷基三甲基铵（C12TAB）改性的蒙脱土（MMT）（一种有机改性MMT）对TPS-聚乙烯（PE）共混物形态的影响。我们观察到两亲性黏土颗粒对TPS-PE界面的增容作用，将TPS-PE界面张力从45 mN/m降低至13.06 mN/m。我们发现MARTINI-3对基于模型MMT的PCNCs性质的估计与AA模拟和实验数据吻合良好，为参数向其他体系的转移性奠定了基础。
英文摘要
Phyllosilicate clays are widely used in polymer nanocomposites owing to their high anisotropy and tunable surface polarity. Their distribution and interface localization in polymer blends can be used to tune the properties of polymer-clay nanocomposites (PCNCs). A coarse-grained (CG) force field for clays can aid molecular simulations in PCNC development. Here, we developed MARTINI-3 parameters, a CG force field with high chemical specificity, for phyllosilicate clays with diverse surface polarities. Initial interactions for the clay functional groups were determined from hydration free energies, obtained by applying the Lifshitz theory to experimental surface tension data. These were fine-tuned using the structural, thermodynamic, and dynamic properties of thermoplastic starch (TPS)-clay composites from all-atom (AA) molecular dynamics (MD) simulations. The radial distribution function and two-body excess entropy of TPS components, not used in CG parameterization, were accurately estimated, establishing the robustness of the parameters. We investigated the effect of clay surface polarity on polymer segmental dynamics and structure-property relationships. The CG parameters were then used to study the effect of dodecyltrimethylammonium (C12TAB)-modified montmorillonite (MMT), an organically-modified MMT, on TPS-polyethylene (PE) blend morphology using large time- and length-scale MD simulations. We observed compatibilization of the TPS-PE interphase by the amphiphilic clay particle, reducing the TPS-PE interfacial tension from 45 mN/m to 13.06 mN/m. We found good agreement between MARTINI-3 estimates for properties of model MMT-based PCNCs and those from AA simulations and experimental data, establishing grounds for the transferability of the parameters to other systems.
