Viscoelastic Properties of Monolayer Lubricant Films during Touch-Down and Take-Off Behavior Measured by Fiber Wobbling Method

It is essential to clarify the interaction between the magnetic head and the monolayer lubricant film coated on the magnetic disk in the design of next-generation hard disk drives with ultra-low flying height. However, with previous measuring methods such as AFM, it was difficult to measure the mech...

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Autores principales: Yuya Hamamoto, Shintaro Itoh, Kenji Fukuzawa, Hedong Zhang
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Publicado: Japanese Society of Tribologists 2011
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spelling oai:doaj.org-article:0500a49c50944583ac02a232765978872021-11-05T09:26:17ZViscoelastic Properties of Monolayer Lubricant Films during Touch-Down and Take-Off Behavior Measured by Fiber Wobbling Method1881-219810.2474/trol.6.83https://doaj.org/article/0500a49c50944583ac02a232765978872011-01-01T00:00:00Zhttps://www.jstage.jst.go.jp/article/trol/6/1/6_1_83/_pdf/-char/enhttps://doaj.org/toc/1881-2198It is essential to clarify the interaction between the magnetic head and the monolayer lubricant film coated on the magnetic disk in the design of next-generation hard disk drives with ultra-low flying height. However, with previous measuring methods such as AFM, it was difficult to measure the mechanical properties of molecularly thin lubricant films with a precisely controlled nanometer-sized gaps. In this study, we applied the fiber wobbling method to clarify the viscoelastic properties of monolayer lubricant films during touch-down and take-off behavior. The fiber wobbling method is the highly-sensitive measurement of shear force we developed and can control the shearing gap with sub-nanometer resolution. The gap dependence of viscoelastic properties was evaluated both in the approaching and the separating processes and their differences and dependencies on the types of lubricant films were discussed. As sample lubricants, we used non-polar and polar perfluoropolyether lubricants: Fomblin Z03 and Fomblin Zdol4000. Three different types of monolayer lubricant films were prepared. The first one consisted of mobile molecules of Z03 only. The second one contained both mobile and bonded molecules of Zdol4000. The third one was only made of bonded molecules of Zdol4000. Our experimental results indicated that the mobile molecules caused the formation of a liquid bridge between solid surfaces and it leads to the hysteresis of viscoelastic properties between approaching and separating processes. On the other hand, the sample only consisted of bonded molecules did not show such a hysteresis.Yuya HamamotoShintaro ItohKenji FukuzawaHedong ZhangJapanese Society of Tribologistsarticlenano-rheologynano-tribologyviscoelastic measurementhead-disk interfacemolecularly thin filmliquid bridgePhysicsQC1-999Engineering (General). Civil engineering (General)TA1-2040Mechanical engineering and machineryTJ1-1570ChemistryQD1-999ENTribology Online, Vol 6, Iss 1, Pp 83-95 (2011)
institution DOAJ
collection DOAJ
language EN
topic nano-rheology
nano-tribology
viscoelastic measurement
head-disk interface
molecularly thin film
liquid bridge
Physics
QC1-999
Engineering (General). Civil engineering (General)
TA1-2040
Mechanical engineering and machinery
TJ1-1570
Chemistry
QD1-999
spellingShingle nano-rheology
nano-tribology
viscoelastic measurement
head-disk interface
molecularly thin film
liquid bridge
Physics
QC1-999
Engineering (General). Civil engineering (General)
TA1-2040
Mechanical engineering and machinery
TJ1-1570
Chemistry
QD1-999
Yuya Hamamoto
Shintaro Itoh
Kenji Fukuzawa
Hedong Zhang
Viscoelastic Properties of Monolayer Lubricant Films during Touch-Down and Take-Off Behavior Measured by Fiber Wobbling Method
description It is essential to clarify the interaction between the magnetic head and the monolayer lubricant film coated on the magnetic disk in the design of next-generation hard disk drives with ultra-low flying height. However, with previous measuring methods such as AFM, it was difficult to measure the mechanical properties of molecularly thin lubricant films with a precisely controlled nanometer-sized gaps. In this study, we applied the fiber wobbling method to clarify the viscoelastic properties of monolayer lubricant films during touch-down and take-off behavior. The fiber wobbling method is the highly-sensitive measurement of shear force we developed and can control the shearing gap with sub-nanometer resolution. The gap dependence of viscoelastic properties was evaluated both in the approaching and the separating processes and their differences and dependencies on the types of lubricant films were discussed. As sample lubricants, we used non-polar and polar perfluoropolyether lubricants: Fomblin Z03 and Fomblin Zdol4000. Three different types of monolayer lubricant films were prepared. The first one consisted of mobile molecules of Z03 only. The second one contained both mobile and bonded molecules of Zdol4000. The third one was only made of bonded molecules of Zdol4000. Our experimental results indicated that the mobile molecules caused the formation of a liquid bridge between solid surfaces and it leads to the hysteresis of viscoelastic properties between approaching and separating processes. On the other hand, the sample only consisted of bonded molecules did not show such a hysteresis.
format article
author Yuya Hamamoto
Shintaro Itoh
Kenji Fukuzawa
Hedong Zhang
author_facet Yuya Hamamoto
Shintaro Itoh
Kenji Fukuzawa
Hedong Zhang
author_sort Yuya Hamamoto
title Viscoelastic Properties of Monolayer Lubricant Films during Touch-Down and Take-Off Behavior Measured by Fiber Wobbling Method
title_short Viscoelastic Properties of Monolayer Lubricant Films during Touch-Down and Take-Off Behavior Measured by Fiber Wobbling Method
title_full Viscoelastic Properties of Monolayer Lubricant Films during Touch-Down and Take-Off Behavior Measured by Fiber Wobbling Method
title_fullStr Viscoelastic Properties of Monolayer Lubricant Films during Touch-Down and Take-Off Behavior Measured by Fiber Wobbling Method
title_full_unstemmed Viscoelastic Properties of Monolayer Lubricant Films during Touch-Down and Take-Off Behavior Measured by Fiber Wobbling Method
title_sort viscoelastic properties of monolayer lubricant films during touch-down and take-off behavior measured by fiber wobbling method
publisher Japanese Society of Tribologists
publishDate 2011
url https://doaj.org/article/0500a49c50944583ac02a23276597887
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AT kenjifukuzawa viscoelasticpropertiesofmonolayerlubricantfilmsduringtouchdownandtakeoffbehaviormeasuredbyfiberwobblingmethod
AT hedongzhang viscoelasticpropertiesofmonolayerlubricantfilmsduringtouchdownandtakeoffbehaviormeasuredbyfiberwobblingmethod
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