Frictional properties of complex polymer brushes

该项目旨在研究复杂聚合物刷的润滑性能。聚合物刷的双层应通过分子动力学模拟与流体动力学相互作用和分析方法进行研究，其中具有附着纳米颗粒的支化聚合物和线性聚合物将作为锚定链形成刷。这些刷子在平衡中显示出有趣的性质，例如形成具有不同构象性质的两个群体，以及在附着纳米颗粒的情况下在构象之间切换的能力。单刷的静态特性的表征后，这种结构的双层的力-距离分布将进行研究。应将结果与已知的理论方法进行比较，如果适用，可以开发新的分析概念。调查的重点将是在稳定剪切运动和高度非平稳过程中，如（准）瞬时反转的剪切方向的润滑性能的影响，这样的结构修改。预期的结果应该让我们深入了解润滑机制，因为它们出现在许多生物系统中，例如在细胞的糖萼。此外，将探讨复杂电刷作为传感器和开关的潜在应用。

The proposed project aims at the investigation of lubrication properties of complex polymer brushes. Bilayers of polymer brushes shall be studied via molecular dynamics simulations with hydrodynamic interactions and analytical methods, where branched polymers and linear polymers with attachednanoparticles will serve as anchored chains to form the brushes. These brushes show interesting properties in equilibrium, such as a formation of two populations with different conformational properties and the ability to switch between conformations in the case of attached nanoparticles. After characterization of static properties of single brushes, the force-distance profiles for bilayers of such structures will be investigated. The results shall be compared to known theoretical approaches, where, if applicable, new analytical concepts may be developed. The focus of the investigations will be on the influence of such structural modifications on the lubrication properties in steady-shear motion and highly non-stationary processes, such as the (quasi-)instantaneous inversion of the shear direction. The expected results should give insight into lubrication mechanisms as they appear in many biological systems, as for instance at the glycocalyx of cells. Furthermore, potential applications of complex brushes as sensors and switches will be explored.