Lubricant pickup on ultra-thin PFPE lubricants with different backbone structure

Lubricant pickup on different PFPE lubricant (Z-tetraol, D-40H, and QA-40) film was compared by the slider surface analyzing tester (SSA tester) developed to observe the lubricant thickness mapping on the slider surfaces after the heads flying on the disk surfaces. These lubricants have same four OH functional end-groups, however, these have the different backbone. Z-tetraol showed smallest amount of lubricant pickup in these lubricants. D-40H and QA-40 showed much pickup at large clearance of 30mW back-off. Pickup volumes of each lubricant disk with similar mobile lubricant thickness were different, and D-40H showed largest pickup volume in these lubricant.