Superlubricity of Zwitterionic Bottlebrush Polymers in the Presence of Multivalent Ions
Superlubricity of Zwitterionic Bottlebrush Polymers in the Presence of Multivalent Ions
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DOI：
10.1021/jacs.0c07215
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发表时间：
2020-09-02
影响因子：
15
通讯作者：
Banquy, Xavier
中科院分区：
文献类型：
--
作者：
Adibnia, Vahid;Olszewski, Mateusz;Banquy, Xavier
在这项研究中，我们报告的润滑性能的物理吸附的两性离子瓶刷聚合物在多价离子的存在下，使用表面力装置。与聚电解质刷不同，在低至0.1 mM浓度的多价离子存在下，其润滑性能急剧下降，而两性离子瓶刷聚合物在多价离子浓度高达中等的情况下表现出低至类似于10（-3 y）的摩擦系数正常负载。这种润滑能力持续存在，直到在高正常载荷下发生表面磨损。表面磨损被证明是由多价离子桥接的聚合物链和脱水的两性离子部分。最后，聚合物膜稳定性的分析表明，在离子存在下聚合物的部分解吸不影响润滑性能。因此，即使在物理吸附状态下，在多价离子存在下，两性离子刷的性能也明显优于共价接枝的两性离子刷。
In this study, we report lubrication properties of physisorbed zwitterionic bottlebrush polymers in the presence of multivalent ions using the surface force apparatus. Unlike polyelectrolyte brushes, the lubrication properties of which diminish drastically in the presence of multivalent ions at concentrations as low as 0.1 mM, zwitterionic bottlebrush polymers exhibit friction coefficients as low as similar to 10(-3y) at such concentrations of multivalent ions up to intermediate normal loads. This lubrication ability persists until surface wear occurs at high normal loads. The surface wear is demonstrated to be triggered by the multivalent ions bridging the polymer chains and dehydrating the zwitterionic moieties. Finally, the analysis of the polymer film stability suggests that the partial desorption of polymers in the presence of the ions does not affect the lubrication performance. Therefore, even in the physisorbed state, zwitterionic brushes perform significantly better than covalently grafted polyelectrolyte brushes in the presence of multivalent ions.