Confined film structure and friction properties of triblock copolymer additives in oil-based lubrication

Yamada, Shinji; Fujihara, Ami; Yusa, Shin Ichi; Tanabe, Tadao; Kurihara, Kazue

doi:10.1038/s41428-018-0114-y

Cited by 6 publications

(4 citation statements)

References 30 publications

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“…Therefore, the unique deformation of the slider surface in the case of PMA-C8 (EH) can only be due to the accumulation of polymers. A similar phenomenon was also reported by Yamada et al…”

Section: Resultssupporting

confidence: 89%

“…Therefore, the unique deformation of the slider surface in the case of PMA-C8 (EH) can only be due to the accumulation of polymers. A similar phenomenon was also reported by Yamada et al 42 The accumulation in the case of PMA-C8 (EH) could be explained from the conformation of its adsorbed film. In particular, the NR results (Figure 1) reveal that the adsorbed film had more loosely adsorbed chains.…”

Section: ■ Results and Discussionsupporting

confidence: 84%

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Effects of Polarity of Polymers on Conformation and Lubricating Film Formation of Adsorbed Films

et al. 2023

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The conformations and lubricating film formation ability of adsorbed films on metal surfaces formed by poly(alkyl methacrylate) (PAMA) homopolymers with different polarities from nonpolar lubricant oil were investigated. It was found that as the polarity of the polymers became higher, the chains in the adsorbed films adsorbed more loosely to the surfaces (i.e., they formed more loops and tails). The loosely adsorbed chains temporarily trapped free polymer chains flowing into the gap between sliding surfaces, resulting in a much thicker lubricating film. Thus, the sliding surfaces were better protected from wear caused by direct contact. On the other hand, flattened chains occupying in the adsorbed film formed by low polarity-polymers could not trap free polymer chains, resulting in a thinner lubricating film.

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“…Therefore, the unique deformation of the slider surface in the case of PMA-C8 (EH) can only be due to the accumulation of polymers. A similar phenomenon was also reported by Yamada et al…”

Section: Resultssupporting

confidence: 89%

Section: ■ Results and Discussionsupporting

confidence: 84%

Effects of Polarity of Polymers on Conformation and Lubricating Film Formation of Adsorbed Films

et al. 2023

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“…If we consider the presence of water hydration shells (layers) at the aggregate/mica and opposing aggregate layer interfaces, then a dynamic thickness of about 3 nm obtained for the two adsorbed layers is almost the minimum thickness attainable for the adsorbed BIPA copolymer. The minimum thickness layer should have a rather rigid property (no more deformation is available for energy dissipation), which is also suitable for extremely low friction. , …”

Section: Resultsmentioning

confidence: 99%

“…The minimum thickness layer should have a rather rigid property (no more deformation is available for energy dissipation), which is also suitable for extremely low friction. 46,47 We should add one more point for the extremely low friction of the BIPA adsorbed layers. It is well known that charged polymer brushes in water are the representative example of low-friction systems; the μ values for the BIPA adsorbed layers are equivalent or smaller.…”

Section: Langmuirmentioning

confidence: 99%

Aqueous Lubrication with the Molecularly Confined Films of Silicone-Based Amphiphilic Block Copolymer Aggregates

et al. 2019

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The confined film structures and tribological properties of the dilute aqueous solution of a silicone-based amphiphilic block copolymer, bis-isobutyl poly(ethylene glycol) (PEG)-14/amodimethicone (BIPA) copolymer, between mica surfaces were investigated. The BIPA copolymer existed as positively charged water-soluble aggregates in the solution. The adsorption behavior of the BIPA copolymer aggregates on a mica surface from solution was studied using an atomic force microscope (AFM); the result showed the immediate formation of a uniform adsorbed BIPA copolymer layer, followed by the gradual deposition of BIPA aggregates on the top of the adsorbed layer. Friction measurements were carried out using the surface forces apparatus (SFA) for the confined films of BIPA copolymer solution between mica surfaces, which revealed two different sliding film structures depending on the elapsed time after surface preparation. The sliding film consisting of two adsorbed BIPA copolymer layers was obtained for a relatively short elapsed time (not longer than 3 h), which had an extremely low friction coefficient μ (of the order of 10–5). The sliding film on the following day (elapsed time of approximately 24 h) had the structure of a deposited/kinetically trapped BIPA aggregate layer confined between the opposing adsorbed layers, and the μ values were within the range from 10–4 to 10–3. Our results suggest that the different elapsed time ranges and resulting absence or presence of the intervening layer of trapped aggregates between the absorbed layers determine the tribological properties of the confined films. Molecular friction mechanisms are discussed for the two sliding structures, which give insight into using amphiphilic block copolymer aggregates for a new class of aqueous lubrication system to design extremely low friction interfaces.

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Investigations of Polymethacrylate Tribochemical Films Using X-Ray Spectroscopy and Optical Profilometry

Erck

Song

et al. 2021

Tribol Lett

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Confined film structure and friction properties of triblock copolymer additives in oil-based lubrication

Cited by 6 publications

References 30 publications

Effects of Polarity of Polymers on Conformation and Lubricating Film Formation of Adsorbed Films

Effects of Polarity of Polymers on Conformation and Lubricating Film Formation of Adsorbed Films

Aqueous Lubrication with the Molecularly Confined Films of Silicone-Based Amphiphilic Block Copolymer Aggregates

Investigations of Polymethacrylate Tribochemical Films Using X-Ray Spectroscopy and Optical Profilometry

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