Effect of reactive end groups on the rheology of disk lubricant systems

Author

Kono, Raymond-Noel ; Jhon, Myung S. ; Choi, Hyoung J. ; Kim, Chul A.

Author_Institution

Seagate Media Res. Center, Fremont, CA, USA

Volume

35

Issue

5

fYear

1999

fDate

9/1/1999 12:00:00 AM

Firstpage

2388

Lastpage

2390

Abstract

We systematically investigate the properties of perfluoropolyethers with different weights and chain-end functionalities, which are used as lubricants in hard disk drive systems. The temperature dependence of the viscosity yields an Arrhenius form; the activation energy and hydrodynamic volume are determined for different molecular weights. The activation energy depends on both end group functionality and molecular weight. Also, modified Cole-Cole plots for storage modulus vs. loss modulus reveal the presence of microstructures due to the interaction of polymer chain-end groups in the bulk. The viscosity-molecular weight relationship exhibits a remarkable crossover behaviour at a critical molecular weight (M_c) for ZdolTX (Zdol with C/O end group ratio of 1.7). Fly stiction (tribology) data also exhibit an M_c and an excellent correlation with viscosity (rheology) is obtained

Keywords

disc drives; hard discs; lubrication; rheology; stiction; viscosity; Arrhenius form; Cole-Cole plots; ZdolTX; activation energy; chain-end functionalities; crossover behaviour; disk lubricant systems; fly stiction data; hard disk drive systems; hydrodynamic volume; loss modulus; molecular weights; perfluoropolyethers; reactive end groups; rheology; storage modulus; viscosity temperature dependence; viscosity-molecular weight relationship; Chemicals; Force measurement; Hard disks; Humidity measurement; Loss measurement; Lubricants; Polymers; Q measurement; Rheology; Viscosity;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/20.800834

Filename

800834