Biomicrofluidics. 2010 Sep 30;4(3):32202. doi: 10.1063/1.3396446.
We use molecular dynamics simulations with a dissipative particle dynamics thermostat to study the behavior of nanosized inclusions (colloids) in a polymer brush under shear whereby the solvent is explicitly included in the simulation. The brush is described by a bead-spring model for flexible polymer chains, grafted on a solid substrate, while the polymer-soluble nanoparticles in the solution are taken as soft spheres whose diameter is about three times larger than that of the chain segments and the solvent. We find that the brush number density profile, as well as the density profiles of the nanoinclusions and the solvent, remains insensitive to strong shear although the grafted chains tilt in direction of the flow. The thickness of the penetration layer of nanoinclusions, as well as their average concentration in the brush, stays largely unaffected even at the strongest shear. Our result manifests the remarkable robustness of polymer brushes with embedded nanoparticles under high shear which could be of importance for technological applications.
我们使用耗散粒子动力学（DPD）热平衡分子动力学模拟来研究剪切下聚合物刷中纳米颗粒（胶体）的行为，其中溶剂在模拟中被明确包含。刷由柔性聚合物链的珠-簧模型描述，接枝在固体基底上，而溶液中的聚合物可溶性纳米颗粒被视为软球，其直径大约是链段和溶剂的三倍。我们发现，尽管接枝链向流动方向倾斜，但刷的数密度分布以及纳米颗粒和溶剂的密度分布对强剪切仍然不敏感。纳米颗粒的穿透层厚度以及它们在刷中的平均浓度即使在最强的剪切下也基本保持不变。我们的结果表明，在高剪切下，嵌入纳米颗粒的聚合物刷具有显著的鲁棒性，这对于技术应用可能很重要。
