Nanolubrication: patterned lubricating films using ultraviolet (UV) irradiation on hard disks

Area of Science:

• Materials Science
• Tribology
• Surface Chemistry

Background:

• Nanolubrication is critical for device functionality, requiring self-sustainability with minimal molecular layers.
• Achieving optimal lubrication involves balancing bonding strength and molecular mobility for surface repair.

Purpose of the Study:

• To investigate the use of long-wavelength UV irradiation to control perfluoropolyether (PFPE) bonding on CN(x) surfaces.
• To evaluate the friction and wear characteristics of different PFPE bonding states for magnetic hard disk applications.

Main Methods:

• Utilized long-wavelength UV irradiation (320-390 nm) to induce PFPE bonding on CN(x) disks.
• Compared lubrication performance of 100% mobile PFPE, 100% bonded PFPE, and a mixture of both.
• Employed lateral force microscopy, atomic force microscopy, and a ball-on-inclined plane apparatus to assess friction and wear.

Main Results:

• The mixed mobile and bonded PFPE system exhibited the highest shear rupture strength.
• UV irradiation effectively controlled the degree of PFPE bonding on the CN(x) coatings.
• Friction and wear characteristics varied significantly based on the PFPE bonding state.

Conclusions:

• A mixed lubrication strategy combining mobile and bonded PFPE offers enhanced self-sustaining lubrication properties.
• Controlled UV-induced bonding is a viable method for tuning nanolubrication performance.
• The findings have implications for improving the durability and reliability of magnetic hard disk drives.