Schellnhuber Kordula, Blass Johanna, Hübner Hanna, Gallei Markus, Bennewitz Roland
INM─Leibniz Institute for New Materials, 66123 Saarbrücken, Germany.
Department of Physics, Saarland University, 66123 Saarbrücken, Germany.
Langmuir. 2024 Jan 9;40(1):968-974. doi: 10.1021/acs.langmuir.3c03190. Epub 2023 Dec 20.
Surface-grafted polymers can reduce friction between solids in liquids by compensating the normal load with osmotic pressure, but they can also contribute to friction when fluctuating polymers entangle with the sliding counter face. We have measured forces acting on a single fluctuating double-stranded DNA polymer, which is attached to the tip of an atomic force microscope and interacts intermittently with nanometer-scale methylated pores of a self-assembled polystyrene--poly(4-vinylpyridine) membrane. Rare binding of the polymer into the pores is followed by a stretching of the polymer between the laterally moving tip and the surface and by a force-induced detachment. We present results for the velocity dependence of detachment forces and of attachment frequency and discuss them in terms of rare excursions of the polymer beyond its equilibrium configuration.
表面接枝聚合物可以通过渗透压补偿法向载荷来降低液体中固体之间的摩擦，但当波动的聚合物与滑动的相对表面缠结时，它们也会增加摩擦。我们测量了作用在单个波动双链DNA聚合物上的力，该聚合物附着在原子力显微镜的尖端，并与自组装聚苯乙烯-聚（4-乙烯基吡啶）膜的纳米级甲基化孔间歇性相互作用。聚合物偶尔与孔结合，随后聚合物在横向移动的尖端和表面之间被拉伸，并因力而脱离。我们给出了脱离力和附着频率与速度的依赖关系结果，并根据聚合物超出其平衡构型的罕见偏移对结果进行了讨论。
