Solvent-induced immiscibility of polymer brushes eliminates dissipation channels
Solvent-induced immiscibility of polymer brushes eliminates dissipation channels
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DOI：
10.1038/ncomms4781
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发表时间：
2014-05-01
影响因子：
16.6
通讯作者：
Mueser, Martin H.
中科院分区：
文献类型：
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作者：
de Beer, Sissi;Kutnyanszky, Edit;Mueser, Martin H.
聚合物刷导致小的摩擦和磨损，因此在工业应用中具有巨大的潜力。然而，相对电刷的交错使它们易于损坏。在这里，我们报告的分子动力学模拟揭示，不混溶刷系统可以形成光滑的接口，其中交错被消除和耗散大大减少。我们测试我们的研究结果与摩擦力显微镜实验亲水性和疏水性刷系统在对称和不对称的设置。在对称设置中，两个刷子在化学上是相似的，而不对称系统由两个不同的刷子组成，每个刷子都喜欢自己的溶剂。在实验测得的力迹线和摩擦减少中观察到的趋势与模拟相似，并延伸到完全浸没的触点。这些结果表明，两个不混溶的刷系统在机械接触滑动在流体-流体界面，同时具有承载能力。这使它们成为摩擦学应用的理想候选者。
Polymer brushes lead to small friction and wear and thus hold great potential for industrial applications. However, interdigitation of opposing brushes makes them prone to damage. Here we report molecular dynamics simulations revealing that immiscible brush systems can form slick interfaces, in which interdigitation is eliminated and dissipation strongly reduced. We test our findings with friction force microscopy experiments on hydrophilic and hydrophobic brush systems in both symmetric and asymmetric setups. In the symmetric setup both brushes are chemically alike, while the asymmetric system consists of two different brushes that each prefer their own solvent. The trends observed in the experimentally measured force traces and the friction reduction are similar to the simulations and extend to fully immersed contacts. These results reveal that two immiscible brush systems in mechanical contact slide at a fluid-fluid interface while having load-bearing ability. This makes them ideal candidates for tribological applications.