目的 研究相结构对十八烷基三氯硅烷（OTS）分子膜纳米机械性能的影响。方法 分别在冰水混合物温度和室温下制备了OTS分子膜的样品，利用原子力显微镜表征表面形貌，通过施加不同的探针作用力观察相对高度差变化。结果 随着针尖作用力的增加，冰水混合物温度下制备的OTS分子膜的相对高度差一直维持在2.02 nm左右；在室温下制备的OTS分子膜，针尖作用力在800 pN以下时，高度值维持在1.73 nm左右；针尖作用力增加到800 pN时，其相对高度差开始下降；当作用力增加到4 nN时，其相对高度差维持在1.44 nm左右。结论 有序致密排列的OTS分子岛具有较强的纳米机械强度，无序疏松的OTS分子岛具有较弱的纳米机械强度，易在较大探针作用力下被压变形。

The work aims to study the effects of phase structure on nano-mechanical strength of octadecyltrichlorosilane (OTS) molecular films. The OTS molecular film samples were prepared at the temperature of ice-water mixture and room temperature, respectively. Morphology of two samples was characterized with AFM, and height difference of the films were observed by applying various tip-loading forces. With the increase of tip-loading force, relative height difference of OTS molecular film prepared at the temperature of ice-water mixture was constantly maintained at nearly 2.02 nm; for the OTS molecular film prepared at room temperature, the relative height difference did not decrease until the tip-loading force increased to 800 pN, and was maintained at nearly 1.44 nm as the force increased to 4 nN. The orderly and densely arranged OTS molecular film is of higher nano-mechanical strength while disorderly and loosely arranged OTS molecular film is of lower nano-mechanical strength, and may be subject to compressive deformation provided with high tip-loading force.