Polymer-nanoparticle interfacial behavior revisited: A molecular dynamics study
Polymer-nanoparticle interfacial behavior revisited: A molecular dynamics study
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重新审视聚合物-纳米粒子界面行为：分子动力学研究
DOI：
10.1039/c0cp02952a
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发表时间：
2011-01-01
影响因子：
3.3
通讯作者：
Cao, Dapeng
中科院分区：
文献类型：
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作者：
Liu, Jun;Wu, Yan;Cao, Dapeng
通过调整聚合物-填料相互作用、填料尺寸和填料负载量，我们使用基于粗粒模型的分子动力学模拟来研究聚合物-填料界面结构（键的方向、链段和链长度尺度、链尺寸和构象）、动态和应力应变特性。模拟结果表明，界面区域由不同聚合物链的部分片段组成，这与Chen等人的实验结果一致。 （高分子，2010，43，1076）。此外，发现界面区域在一个单链尺寸（R-g）范围内，无论聚合物-填料相互作用和填料尺寸如何，超过该范围就会出现本体行为。在界面区域，取向和动态行为由界面焓引起，而填料附近的聚合物链的尺寸和构象由构型熵控制。在强聚合物-填料相互作用（相当于氢键）的情况下，最内部吸附的聚合物链段仍然进行吸附-解吸过程，界面区域链质心的传输表现出远离玻璃态的行为，应力-应变曲线中没有出现类塑性屈服点，这表明虽然界面聚合物链的活动性受到限制，但填料周围不存在“聚合物玻璃层”。此外，事实证明，填料颗粒更喜欢选择性地吸附长聚合物链，以实现有吸引力的聚合物-填料相互作用，验证了结合橡胶（BR）变化的实验解释。简而言之，这项工作为聚合物-纳米颗粒界面行为的进一步实验和模拟研究提供了重要信息。
By tuning the polymer-filler interaction, filler size and filler loading, we use a coarse-grained model-based molecular dynamics simulation to study the polymer-filler interfacial structural (the orientations at the bond, segment and chain length scales, chain size and conformation), dynamic and stress-strain properties. Simulated results indicate that the interfacial region is composed of partial segments of different polymer chains, which is consistent with the experimental results presented by Chen et al. (Macromolecules, 2010, 43, 1076). Moreover, it is found that the interfacial region is within one single chain size (R-g) range, irrespective of the polymer-filler interaction and the filler size, beyond which the bulk behavior appears. In the interfacial region, the orientation and dynamic behaviors are induced by the interfacial enthalpy, while the size and conformation of polymer chains near the filler are controlled by the configurational entropy. In the case of strong polymer-filler interaction (equivalent to the hydrogen bond), the innerest adsorbed polymer segments still undergo adsorption-desorption process, the transport of chain mass center in the interfacial region exhibits away from the glassy behavior, and no plastic-like yielding point appears in the stress-strain curve, which indicates that although the mobility of interfacial polymer chains is restricted, there exist no "polymer glassy layers" surrounding the filler. In addition, it is evidenced that the filler particle prefers selectively adsorbing the long polymer chains for attractive polymer-filler interaction, validating the experimental explanation of the change of the bound rubber (BR). In short, this work provides important information for further experimental and simulation studies of polymer-nanoparticle interfacial behavior.