Scaling from Single Molecule to Macroscopic Adhesion at Polymer/Metal Interfaces
Scaling from Single Molecule to Macroscopic Adhesion at Polymer/Metal Interfaces
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DOI：
10.1021/la504542f
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发表时间：
2015-03-10
期刊：
影响因子：
3.9
通讯作者：
Valtiner, Markus
中科院分区：
文献类型：
--
作者：
Utzig, Thomas;Raman, Sangeetha;Valtiner, Markus
了解基于基本分子相互作用的宏观粘附的演变对于设计在许多工业和生物医学应用中发挥重要作用的坚固且智能的聚合物/金属界面至关重要。在这里，我们展示了如何根据单分子相互作用来预测宏观粘附。特别是，我们在贝尔-埃文斯理论框架下进行动态单分子力谱（SM-AFM），以获得有关胺/金结的束缚态和非束缚态之间的能垒的信息。此外，我们使用 Jarzynskis 方程从这些非平衡力测量中获得胺/金键的平衡基态能量差。此外，我们还进行表面力装置 (SFA) 实验，测量同时形成约 107 个胺/金键的接触处的宏观粘附力。 SFA 方法提供了 (36 +/- 1)k(B)T 的胺/金相互作用能（通过相互作用分子的数量归一化），这与使用 Jarzynskis 方程和单分子 AFM 实验计算的 (35 +/- 3)k(B)T 相互作用自由能非常一致。我们的结果通过测量方程两边来验证聚合物/金属相互作用领域的 Jarzynskis 等式。此外，SFA 和 AFM 的比较显示了如何在单分子相互作用的基础上预测宏观相互作用能，为潜在预测新型胶水或涂层的粘合性能以及生物粘合和湿粘合提供了一种新策略。
Understanding the evolution of macroscopic adhesion based on fundamental molecular interactions is crucial to designing strong and smart polymer/metal interfaces that play an important role in many industrial and biomedical applications. Here we show how macroscopic adhesion can be predicted on the basis of single molecular interactions. In particular, we carry out dynamic single molecule-force spectroscopy (SM-AFM) in the framework of Bell-Evans theory to gain information about the energy barrier between the bound and unbound states of an amine/gold junction. Furthermore, we use Jarzynskis equality to obtain the equilibrium ground-state energy difference of the amine/gold bond from these nonequilibrium force measurements. In addition, we perform surface forces apparatus (SFA) experiments to measure macroscopic adhesion forces at contacts where approximately 107 amine/gold bonds are formed simultaneously. The SFA approach provides an amine/gold interaction energy (normalized by the number of interacting molecules) of (36 +/- 1)k(B)T, which is in excellent agreement with the interaction free energy of (35 +/- 3)k(B)T calculated using Jarzynskis equality and single-molecule AFM experiments. Our results validate Jarzynskis equality for the field of polymer/metal interactions by measuring both sides of the equation. Furthermore, the comparison of SFA and AFM shows how macroscopic interaction energies can be predicted on the basis of single molecular interactions, providing a new strategy to potentially predict adhesive properties of novel glues or coatings as well as bio- and wet adhesion.