The 9th International Conference on Multiscale Materials Modeling

Presentation information

Symposium

O. Tribology and Interface: Multi-Scale, Multi-Physics, and Multi-Chemistry Phenomena in Friction, Lubrication, Wear, and Adhesion

[SY-O8] Symposium O-8

Wed. Oct 31, 2018 4:00 PM - 5:00 PM Room5

Chairs: Tianbao Ma(Tsinghua University, China), Yang Wang(Institute for Materials Research, Tohoku University, Japan)

[SY-O8] Coarse-Grained Molecular Dynamic Simulation on the Wear Mechanism of Polymer Brush with Different Chain Topologies

Zhongmin Liu, Shuichi Uehara, Jingxiang Xu, Yusuke Ootani, Nobuki Ozawa, Momoji Kubo (Institute for Material Research,Tohoku Univ., Japan)

As a low friction material, polymer brush has attracted attention in many areas because of its good frictional properties and biological compatibility. The frictional properties of polymer brush are improved by different chain topologies. However, the effects of the chain topologies on the wear of polymer brush are still not clear. To reduce the wear of the polymer brush, it is required to understand the wear behaviors and mechanism of different topological polymer brush. However, in-situ observation of the sliding interface at the molecular scale is difficult. Thus, we investigated the wear mechanism of polymer brush with different topological chain by using coarse-grained molecular dynamics (CGMD) method.

We perform friction simulations of linear polymer brush, cyclic polymer brush where the polymer chains have cyclic structure, and crosslinked polymer brush where the polymer chains are connected with the neighboring polymer chain with crosslinker to understand the effect of chain topologies on the wear. We found that cyclic polymer brush and crosslinked polymer brush had smaller number of dissociation than linear polymer brush because the cyclic polymer brush and crosslinked polymer brush showed smaller frictional forces than that of linear polymer brush. We found that the cyclic polymer brush and crosslinked polymer brush had less interpenetrating beads than that of linear polymer brush. Therefore, the cyclic polymer brush and crosslinked polymer brush have smaller entanglements, leading to the low frictional force. We conclude that chain topologies of polymer brush can improve the wear resistance because they suppress the interpenetration at the sliding interface.