Thermal and directed motion in molecular friction processes investigated by atomic and photonic force microscopy

通过原子和光子力显微镜研究分子摩擦过程中的热运动和定向运动

• 批准号: 420798410
• 负责人: Professor Dr. Thorsten Hugel
• 金额: --
• 依托单位: Institut für Physikalische Chemie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/420798410?language=en
• 关键词: Thermal; directed; motion; molecular; friction

Friction is a complex process of energy dissipation, which is important on most length scales, time scales and across disciplines. Several theories approach the molecular origin of friction, but a comprehensive understanding is still missing. Usually, friction is quantified by a friction coefficient. Two main routes to determine the friction coefficient, either from a directed motion or from thermal motion, can be addressed.Here we use a combination of the complementary approaches Atomic Force Microscopy(AFM) and Photonic Force Microscopy (PFM) to obtain a better understanding of molecular friction at soft (bio)interfaces. Towards that aim, we propose direction and frequency dependent measurements on different bead-surface model systems, which are decorated with well-defined binding partners. We are in particular interested, how the friction coefficients obtained from directed and thermal motion are related. In this context, we will address the question on how single molecule friction and adhesion are related. Finally, we will investigate cooperativity in molecular friction, which we believe is key in understanding how molecular friction properties determine macroscopic friction.Altogether our combined experimental approach will yield unprecedented insights into themolecular origins of frictions from various perspectives, which will help to better understand functionalized interfaces and hydrogels as well as biological transport processes.

摩擦是一个复杂的能量耗散过程，对于大多数长度尺度、时间尺度和跨学科都很重要。有几种理论探讨了摩擦的分子起源，但仍然缺乏全面的理解。通常，摩擦力通过摩擦系数来量化。可以解决确定摩擦系数的两种主要途径，无论是定向运动还是热运动。在这里，我们结合使用原子力显微镜 (AFM) 和光子力显微镜 (PFM) 的互补方法来更好地了解软（生物）界面处的分子摩擦。为了实现这一目标，我们提出了对不同珠表面模型系统进行方向和频率相关的测量，这些模型系统用明确定义的结合伙伴进行装饰。我们特别感兴趣的是，从定向运动和热运动获得的摩擦系数如何相关。在这种情况下，我们将解决单分子摩擦力和粘附力如何相关的问题。最后，我们将研究分子摩擦中的协同性，我们认为这是理解分子摩擦特性如何决定宏观摩擦的关键。总之，我们的组合实验方法将从各个角度对摩擦的分子起源产生前所未有的见解，这将有助于更好地理解功能化界面和水凝胶以及生物运输过程。