w7_AFM_PFPE_Liu

w7_AFM_PFPE_Liu - Nanotribological Characterization of...

Info iconThis preview shows pages 1–9. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Nanotribological Characterization of Molecularly-Thick Boundary Layers of Perfluoropolyether Lubricants for Applications to MEMS/NEMS by Atomic Force Microscopy Prof. Bharat Bhushan Nanotribology Laboratory for Information Storage and MEMS/NEMS Outline Introduction Need of Lubrication for MEMS/NEMS Properties of PFPEs Use of PFPEs for magnetic head-disk interface Objective Experimental Results Friction and adhesion Velocity effect RH effect Temperature effect Durability Summary Need of lubrication for MEMS/NEMS The ideal lubricant for MEMS/NEMS should have the following attributes: Molecularly thick film Easy to be deposited Chemically bonded to substrate Insensitive to environment Properties of PFPEs Low surface tension and low contact angle which allow easy spreading on surfaces and provide hydrophobic property Chemical and thermal stability which minimize degradation Low vapor pressure which provides low out-gassing High adhesion to substrate via organofunctional bonds Good lubricity which reduces the contact surface wear Application of PFPEs for magnetic head-disk interface Diamond like carbon overcoat 3.5 nm thick Al 2 O 3-TiC MR type picoslider Magnetic rigid disk drive 2 nm 8-10 nm 25-75 nm 0.78-1.3 mm Magnetic hard disk Objective Can we use PFPE for the lubrication of MEMS/NEMS? What are the effects of rest time, velocity, relative humidity, and temperature on friction and adhesion of PFPE? What is the influence of polar group, surface bonding, and viscosity on the lubrication performance? Z-15 Z-DOL H O F C Molecule structures of Z-15 and Z-DOL Experimental Typical properties of Z-DOL and Z-15 Z-15 Z-DOL (2000) Formula CF 3-O-( CF 2-CF 2-O) m- (CF 2-O) n-CF 3 * HO-CH 2-CF 2-O-(CF 2- CF 2 O) m-(CF 2-O) n-CF 2- CH 2-OH * Molecular weight (Daltons) 9100 2000 Density 20 o C (g/cm 3 ) 1.84 1.81 Kinematic Viscosity (cSt) 20 o C 38 o C 99 o C 148 90 25 85 34-- Surface tension (dynes/cm) 20 o C 24 24 * m/n ~ 2/3...
View Full Document

Page1 / 23

w7_AFM_PFPE_Liu - Nanotribological Characterization of...

This preview shows document pages 1 - 9. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online