Effect of Polymer Architecture on the Structure and Interactions of Polymer Grafted Particles: Theory and Simulations,Macromolecules

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Effect of Polymer Architecture on the Structure and Interactions of Polymer Grafted Particles: Theory and Simulations
Macromolecules ( IF 5.1 ) Pub Date : 2017-06-09 00:00:00 , DOI: 10.1021/acs.macromol.7b00524
Kevin J. Modica ₁ , Tyler B. Martin ₁ , Arthi Jayaraman ₁

Affiliation

We use Langevin dynamics simulations and Polymer Reference Interaction Site Model (PRISM) theory to study polymer grafted nanoparticles specifically to explain the impact of comb polymer architecture on the grafted layer structure and effective interparticle interactions in solvent and in matrix polymer. First, we use simulations to study a single particle grafted with comb polymers with varying comb polymer design (i.e., spacing and length of side chains along the comb polymer backbone), grafting density (i.e., polymer chains/particle surface area), and particle curvature in implicit solvent at the athermal limit. We find that increasing side chain length or decreasing side chain spacing along the comb polymer effectively swells and extends the polymer backbone due to the increasing side chain monomer crowding. For particles at finite curvature with increasing side chain monomer crowding, the monomer concentration profile of the comb polymer backbone at short distances from the surface resembles the concentration profile of a semiflexible linear polymer and at farther distances resembles that of flexible linear polymers grafted to a flat surface. As the particle curvature decreases to zero (i.e., flat surface), increasing side chain crowding has a simpler effect of expanding the grafted layer without changing the overall shape of the concentration profile. To understand how architecture affects the interactions of the comb polymer grafted particles, we use PRISM theory to calculate the potential of mean force (PMF) between comb polymer grafted particles in implicit solvent, explicit solvent, and explicit matrix of athermal linear polymers. On the basis of the PMFs calculated for a wide range of design parameters (grafting density, comb polymer design), we find that, compared to linear polymers, the comb polymers exhibit stronger effective attraction in the PMF between the grafted particles in both small molecule solvent and polymer matrix due to the increased crowding in the grafted layer from the comb polymer side chains. Interestingly, the PMF between the grafted particles in a small molecule solvent is more sensitive to the comb polymer design (i.e., side chain length and spacing) than the PMF between the grafted particles in a polymer matrix.

中文翻译：

聚合物结构对聚合物接枝颗粒结构和相互作用的影响：理论和模拟

我们使用Langevin动力学模拟和聚合物参考相互作用位点模型（PRISM）理论来研究聚合物接枝的纳米颗粒，专门解释梳状聚合物结构对接枝层结构的影响以及溶剂和基质聚合物中有效的颗粒间相互作用。首先，我们使用模拟研究以不同的梳状聚合物设计（即沿着梳状聚合物主链的侧链的间距和长度），接枝密度（即聚合物链/颗粒表面积）和颗粒接枝有梳状聚合物的单个颗粒隐性溶剂在无热极限下的曲率。我们发现，由于侧链单体拥挤的增加，沿着梳形聚合物的侧链长度的增加或侧链间距的减小会有效地膨胀和延伸聚合物主链。对于有限曲率且侧链单体拥挤程度增加的粒子，梳状聚合物主链的单体浓度分布在距表面较短的距离处类似于半柔性线性聚合物的浓度分布，而在更远的距离处则类似于接枝到平面上的柔性线性聚合物的浓度分布表面。随着粒子曲率减小到零（即平坦表面），增加侧链拥挤具有更简单的扩展接枝层的效果，而不会更改浓度分布的总体形状。为了了解体系结构如何影响梳形聚合物接枝颗粒之间的相互作用，我们使用PRISM理论计算了在非热线性聚合物的隐式溶剂，显式溶剂和显式基质中，梳形聚合物接枝颗粒之间的平均力（PMF）。根据针对广泛设计参数（接枝密度，梳型聚合物设计）计算的PMF，我们发现，与线性聚合物相比，梳型聚合物在两种小分子中的接枝颗粒之间的PMF中均表现出更强的有效吸引力由于梳状聚合物侧链在接枝层中的拥挤增加，因此溶剂和聚合物基质成为可能。有趣的是，在小分子溶剂中的接枝颗粒之间的PMF比在聚合物基质中的接枝颗粒之间的PMF对梳形聚合物的设计（即侧链长度和间距）更敏感。由于梳状聚合物侧链对接枝层的拥挤增加，梳状聚合物在小分子溶剂和聚合物基质中的接枝颗粒之间的PMF中表现出更强的有效吸引力。有趣的是，在小分子溶剂中的接枝颗粒之间的PMF比在聚合物基质中的接枝颗粒之间的PMF对梳形聚合物的设计（即侧链长度和间距）更敏感。由于梳状聚合物侧链对接枝层的拥挤增加，梳状聚合物在小分子溶剂和聚合物基质中的接枝颗粒之间的PMF中表现出更强的有效吸引力。有趣的是，在小分子溶剂中的接枝颗粒之间的PMF比在聚合物基质中的接枝颗粒之间的PMF对梳形聚合物的设计（即侧链长度和间距）更敏感。

更新日期：2017-06-09

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