采用分子自组装成膜技术,在磁头表面制备了1H,1H,2H,2H-全氟癸烷基三乙氧基硅烷(FTE)自组装膜。使用时间飞行二次离子质谱仪(TOF-S IM S)、X射线光电子能谱仪(XPS)、原子力显微镜(AFM)和接触角测量仪对FTE自组装膜进行了表征。XPS测得的FTE自组装膜C 1s谱图中有分谱出现在287.905 eV位置,这证明FTE分子以C—O—S i键与磁头表面结合。通过分析TOF-S IM S测量的不同反应时间的膜厚和其对应的AFM表面形貌图发现,FTE自组装膜形成过程分为表面亚单层膜低覆盖、表面亚单层膜中等覆盖、团聚和聚结4个阶段。实验结果表明,控制反应时间可以在磁头表面制备超薄平整的FTE自组装膜,膜厚为(1.20±0.01)nm,表面粗糙度小于0.2 nm。该层超薄膜使磁头对水的接触角增加到110.5°±0.1,°令磁头的疏水性能得到很大提高,进而较大幅度地提高了磁头表面的抗污染能力。
This study investigates the effect of the incident angle on the trajectory of a nanoparticle and the damaged region on a silicon surface, by molecular dynamic simulation of the collision and recoil of a nanoparticle with a monocrystlline silicon surface. With the change of the inci-dent angle, the recoil angle of the particle changes in a large range from an obtuse angle to an acute angle. The incident angle determines which part of the particle is in contact with the surface when the particle penetrates into the deepest position. Furthermore, it is the contacting part of the particle that the released elastic deformation energy of the surface acts on. These lead to the phenomenon that the recoil angle is sensitive to the incident angle in the collision process at a nanoscale. A depressed region is formed on the surface after the collision. The shape of the damaged region changes from a deep scoop to a flat arc, which is consistent with the trajec-tory of the particle. Some silicon atoms on the surface are extruded out by the incident particle, and form a pileup at the rim of the depressed region.
