The characterization of micro-surface mechanical and electrical properties of the natural rock materials remains inadequate, and their macroscopic performance can be better comprehended by investigating the surface properties. With this purpose, the present research focuses on characterizing the micro-surface morphology, Derjaguin-Muller-Toporov (DMT) modulus, adhesion, and potential of granite, shale, and limestone by employing the atomic force microscope (AFM) as a pioneer attempt. The results show that the micro-surface morphology of the rock fluctuates within hundreds of nanometers, among which the granite micro-surface is comparatively the smoothest, followed by limestone. The morphology of the shale is the roughest, indicating that the regional difference of shale micro-surface is dominant. The distribution of the adhesion on rock micro-surface is uneven; the average adhesion of eight measuring areas for shale is 23.93 nN, accounting for three times of granite and limestone, while the surface DMT modulus of shale is relatively lower than granite and limestone. It is inferred from the obtained results that higher surface adhesion is helpful to the gas adsorption of shale, and the lower surface DMT (elastic) modulus is useful to the formation of fractures and pores. Thus, these two are the micromechanical basis of shale gas adsorption. Additionally, introducing a method to reduce the surface adhesion will benefit the exploration of unconventional resources such as shale gas. The micro-surface of the three types of rocks all shows electricity, with average potential ranging from tens of millivolts to hundreds of millivolts. Besides, the micro-surface potential of the rocks are heterogeneous, and both positive and negative points can be found. The existence and uneven distribution of micro-surface potential provide a robust physical basis for the electromagnetic radiation generated by rock fracture under loading. This study offers a new method for revealing the adsorption characteristics of unconventional gas reservoir rocks and the electromagnetic radiation mechanism of the rock fracture.

天然岩石材料的微观表面力学和电学性质的表征仍然不足，通过研究表面性质可以更好地理解其宏观性能。为此，本研究的重点是利用原子力显微镜 (AFM) 作为先驱尝试，对花岗岩、页岩和石灰岩的微表面形态、Derjaguin-Muller-Toporov (DMT) 模量、粘附性和潜力进行表征。 . 结果表明，岩石的微观表面形态在数百纳米范围内波动，其中花岗岩微观表面较为光滑，其次是石灰岩。页岩形态最为粗糙，表明页岩微表面区域差异占主导地位。岩石微表面附着力分布不均匀；页岩8个测区的平均黏附力为23.93 nN，是花岗岩和石灰岩的3倍，而页岩的表面DMT模量相对低于花岗岩和石灰岩。由所得结果推断，较高的表面附着力有利于页岩的气体吸附，较低的表面DMT（弹性）模量有利于裂缝和孔隙的形成。因此，这两者是页岩气吸附的微观力学基础。此外，引入降低表面附着力的方法将有利于页岩气等非常规资源的勘探。三种岩石的微观表面都显示出电，平均电位从几十毫伏到几百毫伏不等。除了，岩石的微观表面势不均匀，正负点都可以找到。微表面电势的存在和不均匀分布为岩石在荷载作用下断裂产生的电磁辐射提供了坚实的物理基础。该研究为揭示非常规气藏岩石的吸附特征及岩石裂缝的电磁辐射机制提供了一种新的方法。