Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland.
J Am Chem Soc. 2013 Feb 20;135(7):2628-34. doi: 10.1021/ja310255s. Epub 2013 Feb 11.
Understanding the influence of water layers adjacent to interfaces is fundamental in order to fully comprehend the interactions of both biological and nonbiological materials in aqueous environments. In this study, we have investigated hydration forces at the mica-electrolyte interface as a function of ion valency and concentration using subnanometer oscillation amplitude frequency modulation atomic force microscopy (FM-AFM). Our results reveal new insights into the nature of hydration forces at interfaces due to our ability to measure high force gradients without instability and in the absence of lateral confinement due to the use of an atomically sharp tip. We demonstrate the influence of electrolytes on the properties of both primary and structural hydration forces and reveal new insights into the interplay between these phenomena in determining the interaction forces experienced by a nanoscale object approaching an interface. We also highlight the difficulty in directly comparing hydration force data from different measurement techniques where the nature of the perturbation induced by differing interaction geometries is likely to dramatically affect the results.
为了充分理解生物和非生物材料在水相环境中的相互作用，了解相邻界面的水层的影响是至关重要的。在这项研究中，我们使用亚纳米级振荡幅度频率调制原子力显微镜（FM-AFM）研究了云母-电解质界面的水化力随离子价态和浓度的变化。由于我们能够在没有不稳定性的情况下测量高力梯度，并且由于使用原子级锋利的尖端而不存在侧向限制，因此我们的结果为界面处水化力的性质提供了新的见解。我们展示了电解质对初级和结构水化力性质的影响，并揭示了这些现象在确定纳米级物体接近界面时所经历的相互作用力之间相互作用的新见解。我们还强调了在直接比较不同测量技术的水化力数据时存在的困难，其中由不同相互作用几何形状引起的扰动的性质很可能会极大地影响结果。
