Wear detection of candidate MEMS/NEMS lubricant films using atomic force microscopy-based surface potential measurements

The wear of a perfluoropolyether lubricant applied on silicon was investigated using atomic force microscopy-based surface potential measurements. An increase in surface potential is attributed to the change in the work function of silicon after wear and electrostatic charge build-up of debris in the lubricant. Thermally treated coatings containing a mobile lubricant fraction (i.e. partially bonded) were better able to protect silicon from wear compared with the fully bonded and untreated coatings. This enhanced protection is attributed to lubricant replenishment.