Bonding Mechanism of Perfluoropolyether Lubricant Film with Functional Endgroup on Magnetic Disks by Ultraviolet Irradiation

Tani, Hiroshi; Kitagawa, Hiroaki; Tagawa, Norio

doi:10.1007/s11249-011-9867-6

Cited by 17 publications

(14 citation statements)

References 13 publications

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“…Bonding of PFPE type lubricant on the hard disk surface could also be enhanced upon a short period of UV irradiation, depending on the end group of PFPE. The presence of hydroxy group facilitates the formation of stronger bonding than PFPE lubricant without terminal polar group due to the occurrence of selective dissociation of the end groups after UV irradiation as well as subsequent interaction between lubricant and hard disk surface …”

Section: Resultsmentioning

confidence: 99%

Synthesis and properties of cyclotriphosphazene and perfluoropolyether‐based lubricant with polar functional groups

Wang

Tan

Cho

et al. 2016

Lubrication Science

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A novel hard disk lubricant IDL2 was synthesised by reacting sodium 4‐((2,2‐dimethyl‐1,3‐dioxolan‐4‐yl)methoxy)phenoate with hexachlorocyclotriphosphazene, followed by treatment with 1H,1H‐perfluoro‐3,6,9‐trioxatridecan‐1‐ol in the presence of sodium hydride and subsequent hydrolysis using sulfuric acid. The chemical structure of IDL2 was confirmed by proton nuclear magnetic resonance (1H NMR), phosphorus‐31 (31P) NMR spectroscopy and mass spectrometer. The thermal property of IDL2 was analysed using thermal gravimetric analysis (TGA) and it shows better thermal stability than two commercial lubricants Z‐DOL and Z‐Tetraol with two and four terminal hydroxy groups, respectively. IDL2 was found to have comparable hydrophobicity to commercial lubricants Z‐DOL, A20H and Z‐Tetraol with water contact angles in the range of 78 – 85°, revealing that IDL2 has analogous surface energy to these commercial lubricants. IDL2 exhibits comparable friction coefficient to A20H and Z‐Tetraol, but much lower than Z‐DOL. More interestingly, it has a much high bonding ratio when compared with commonly used commercial lubricants under the same testing conditions due to the presence of two polar hydroxy groups, which enhance the interaction between lubricant and substrate. These promising properties of IDL2 show that it would be very potential for real application as a hard disk drive lubricant. Copyright © 2016 John Wiley & Sons, Ltd.

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Section: Resultsmentioning

confidence: 99%

Synthesis and properties of cyclotriphosphazene and perfluoropolyether‐based lubricant with polar functional groups

Wang

Tan

Cho

et al. 2016

Lubrication Science

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“…This indicates that these profiles are mainly formed by the movement of lubricant and plastic deformation. Figures 5,6,and 7 show protuberances at the beginning of the wear test and grooves at the end, for the A20H, D-4OH, and 1.6 nm thick Z-tetraol samples, respectively. Figure 8 shows that the entire protuberance profile for the 2.6 nm thick Z-tetraol sample is like a gently sloping hill.…”

Section: Resultsmentioning

confidence: 99%

“…Perfluoropolyether (PFPE) is a polymer consisting of carbon, oxygen, and fluorine. Functionalized PFPE lubricants have been investigated to improve the retention and replenishment of the lubricant on DLC films [7,8].…”

Section: Introductionmentioning

confidence: 99%

“…These properties are dictated by the molecular structure of the lubricant, including its amounts and chemical states of carbon, fluorine, and oxygen. Polar hydroxyl groups of the lubricant provide good adhesion to the DLC film, while the hydrophobic PFPE backbone protects the DLC film [4][5][6][7][8][9]. 2.6 nm) Z-Tetraol ( The durability of a magnetic disk upon sliding at the head-disk interface is affected by the disks wear properties.…”

Section: Introductionmentioning

confidence: 99%

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Improving the Friction Durability of Magnetic Head-Disk Interfaces by Thin Lubricant Films

Miyake

Suzuki

Miyake

2016

Journal of Nanomaterials

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Nanowear and viscoelasticity were evaluated to study the nanotribological properties of lubricant films of Z-tetraol, D-4OH, and A20H, including their retention and replenishment properties. For A20H and thick Z-tetraol-coated disks, the disk surface partially protrudes, and the phase lag (tan ) increases with friction. This result is consistent with replenishment of the lubricant upon tip sliding. For the D-4OH-coated disk, the tan value decreases with tip sliding, similar to the case for the unlubricated disk. The durability of the lubricant-coated magnetic disks was then evaluated by load increase and decrease friction tests. The friction force of the unlubricated disk rapidly increases after approximately 30 reciprocating cycles, regardless of the load. The lubrication state can be estimated by mapping the dependence of friction coefficient on the reciprocating cycle number and load. The friction coefficient can be classified into one of four areas. The lowest friction area constitutes fluid lubrication. The second area constitutes the transition to mixed lubrication. The third area constitutes boundary lubrication. The highest friction of the fourth area results from surface fracture. The boundary lubricating area of the A20H lubricant was wide, because of its good retention and replenishment properties.

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“…On the other hand, the ultraviolet (UV) irradiation process is generally used to obtain highly chemically bonded lubricant films. Tani et al [8] suggested the occurrence of three kinds of mechanisms on the normal UV process for magnetic disks. First, PFPE lubricants bond to the DLC surface because of the photodissociation of the end groups by the UV light.…”

Section: Introductionmentioning

confidence: 99%

Improvement in Heat Resistance of Perfluoropolyether Lubricant Films on Magnetic Disks by UV Irradiation with a Bias Voltage on the Disk Surface

et al. 2016

Self Cite

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Our previous study confirmed that the photoelectron-assisted ultraviolet (UV) irradiation with a bias voltage between the magnetic disk and the counter electrode above the disk surface increased the bonded ratio of a perfluoropolyether lubricant film on the disk surface. In this study, two types of lubricant materials (Fomblin Z-tetraol and Moresco ADOH) were prepared and coated on disks. After coating the lubricant films, UV irradiation of the lubricated disk surface was performed using the normal process and the photoelectron-assisted process, and the depletions of these lubricant films were compared using the pin-on-disk test with the laser heating function. The results showed that the lubricant film treated with normal UV irradiation without the bias voltage showed a deeper depletion of the lubricant film than that treated with photoelectron-assisted UV irradiation, and the ADOH film showed a shallower depletion than the Z-tetraol film. However, the molecular weight distributions of the ADOH films on DLC surfaces treated by UV irradiation were compared using time-of-flight secondary ion mass spectroscopy, and the film treated with photoelectron-assisted UV irradiation did not change owing to dissociation after photoelectron capture. Photoelectron-assisted UV irradiation led to the decomposition of the cyclo-triphosphazene end groups. Therefore, it is assumed that the depletion of lubricant films treated with photoelectron-assisted UV irradiation was reduced, since the bonding strength to the DLC surface increased because of the greater decomposition of end groups.

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Bonding Mechanism of Perfluoropolyether Lubricant Film with Functional Endgroup on Magnetic Disks by Ultraviolet Irradiation

Cited by 17 publications

References 13 publications

Synthesis and properties of cyclotriphosphazene and perfluoropolyether‐based lubricant with polar functional groups

Synthesis and properties of cyclotriphosphazene and perfluoropolyether‐based lubricant with polar functional groups

Improving the Friction Durability of Magnetic Head-Disk Interfaces by Thin Lubricant Films

Improvement in Heat Resistance of Perfluoropolyether Lubricant Films on Magnetic Disks by UV Irradiation with a Bias Voltage on the Disk Surface

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