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

Shinji Yamada; Ami Fujihara; Shin ichi Yusa; Tadao Tanabe; Kazue Kurihara

doi:10.1038/s41428-018-0114-y

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

Shinji Yamada, Ami Fujihara, Shin ichi Yusa, Tadao Tanabe, Kazue Kurihara

New Industry Creation Hatchery Center (NICHe)

Research output: Contribution to journal › Article › peer-review

5 Citations (Scopus)

Abstract

Abstract: The friction properties of a dilute solution of block copolymer additives in poly-α-olefin (PAO) confined between mica surfaces were investigated using the surface forces apparatus. Friction measurements were made for poly(11-acrylamidoundecanoic acid)-block-poly(alkyl methacrylate)-block-poly(11-acrylamidoundecanoic acid) with an alkyl chain length of C12 (A₅L₉₄₆A₅) in the poly(alkyl methacrylate) blocks. The results were compared to those for a PAO solution of a similar triblock copolymer with an alkyl chain length of C18 (A₅S₉₉₂A₅) examined in our previous work (Yamada et al., Langmuir 2015). The friction coefficient μ for A₅L₉₄₆A₅/PAO was approximately 0.5, which was one or two orders of magnitude larger than that for A₅S₉₉₂A₅/PAO (μ of 0.002–0.039). Detailed analysis of the dynamic thickness and contact geometry enabled us to investigate the difference in the friction reduction abilities of the two additives. A₅L₉₄₆A₅ has a high affinity to PAO and the molecules have expanded conformation in PAO; extensive chain entanglement effect results in the formation of a thick and viscous lubricant layer, which gives rise to high friction. On the other hand, A₅S₉₉₂A₅ has low affinity to PAO, and the shrunken A₅S₉₉₂A₅ molecules adsorbed on the surfaces form a rigid slip plane at the interface, which gives rise to low friction. Our results provide insights into the oil/additive combinations used for low friction in oil-based lubrication.

Original language	English
Pages (from-to)	41-49
Number of pages	9
Journal	Polymer Journal
Volume	51
Issue number	1
DOIs	https://doi.org/10.1038/s41428-018-0114-y
Publication status	Published - 2019 Jan 1

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@article{c93108d19dea4d58b7842902413933e5,

title = "Confined film structure and friction properties of triblock copolymer additives in oil-based lubrication",

abstract = "Abstract: The friction properties of a dilute solution of block copolymer additives in poly-α-olefin (PAO) confined between mica surfaces were investigated using the surface forces apparatus. Friction measurements were made for poly(11-acrylamidoundecanoic acid)-block-poly(alkyl methacrylate)-block-poly(11-acrylamidoundecanoic acid) with an alkyl chain length of C12 (A5L946A5) in the poly(alkyl methacrylate) blocks. The results were compared to those for a PAO solution of a similar triblock copolymer with an alkyl chain length of C18 (A5S992A5) examined in our previous work (Yamada et al., Langmuir 2015). The friction coefficient μ for A5L946A5/PAO was approximately 0.5, which was one or two orders of magnitude larger than that for A5S992A5/PAO (μ of 0.002–0.039). Detailed analysis of the dynamic thickness and contact geometry enabled us to investigate the difference in the friction reduction abilities of the two additives. A5L946A5 has a high affinity to PAO and the molecules have expanded conformation in PAO; extensive chain entanglement effect results in the formation of a thick and viscous lubricant layer, which gives rise to high friction. On the other hand, A5S992A5 has low affinity to PAO, and the shrunken A5S992A5 molecules adsorbed on the surfaces form a rigid slip plane at the interface, which gives rise to low friction. Our results provide insights into the oil/additive combinations used for low friction in oil-based lubrication.",

author = "Shinji Yamada and Ami Fujihara and Yusa, {Shin ichi} and Tadao Tanabe and Kazue Kurihara",

note = "Funding Information: Fig. 2 Schematic illustration describing the contact interface in the SFA friction measurement. Smooth mica surfaces are separated by the molecularly thin films of the A5L946A5/PAO solution. The contact interface is compressed under an applied load L. The lower surface is moved laterally at a constant sliding velocity V. The upper surface is supported by a friction measuring spring and friction force F is measured by the deflection of the spring. Simultaneous observation of FECO fringes enables us to measure the film thickness D and real contact area A during the friction measurement Publisher Copyright: {\textcopyright} 2018, The Society of Polymer Science, Japan.",

year = "2019",

month = jan,

day = "1",

doi = "10.1038/s41428-018-0114-y",

language = "English",

volume = "51",

pages = "41--49",

journal = "Polymer Journal",

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T1 - Confined film structure and friction properties of triblock copolymer additives in oil-based lubrication

AU - Yamada, Shinji

AU - Fujihara, Ami

AU - Yusa, Shin ichi

AU - Tanabe, Tadao

AU - Kurihara, Kazue

N1 - Funding Information: Fig. 2 Schematic illustration describing the contact interface in the SFA friction measurement. Smooth mica surfaces are separated by the molecularly thin films of the A5L946A5/PAO solution. The contact interface is compressed under an applied load L. The lower surface is moved laterally at a constant sliding velocity V. The upper surface is supported by a friction measuring spring and friction force F is measured by the deflection of the spring. Simultaneous observation of FECO fringes enables us to measure the film thickness D and real contact area A during the friction measurement Publisher Copyright: © 2018, The Society of Polymer Science, Japan.

PY - 2019/1/1

Y1 - 2019/1/1

N2 - Abstract: The friction properties of a dilute solution of block copolymer additives in poly-α-olefin (PAO) confined between mica surfaces were investigated using the surface forces apparatus. Friction measurements were made for poly(11-acrylamidoundecanoic acid)-block-poly(alkyl methacrylate)-block-poly(11-acrylamidoundecanoic acid) with an alkyl chain length of C12 (A5L946A5) in the poly(alkyl methacrylate) blocks. The results were compared to those for a PAO solution of a similar triblock copolymer with an alkyl chain length of C18 (A5S992A5) examined in our previous work (Yamada et al., Langmuir 2015). The friction coefficient μ for A5L946A5/PAO was approximately 0.5, which was one or two orders of magnitude larger than that for A5S992A5/PAO (μ of 0.002–0.039). Detailed analysis of the dynamic thickness and contact geometry enabled us to investigate the difference in the friction reduction abilities of the two additives. A5L946A5 has a high affinity to PAO and the molecules have expanded conformation in PAO; extensive chain entanglement effect results in the formation of a thick and viscous lubricant layer, which gives rise to high friction. On the other hand, A5S992A5 has low affinity to PAO, and the shrunken A5S992A5 molecules adsorbed on the surfaces form a rigid slip plane at the interface, which gives rise to low friction. Our results provide insights into the oil/additive combinations used for low friction in oil-based lubrication.

AB - Abstract: The friction properties of a dilute solution of block copolymer additives in poly-α-olefin (PAO) confined between mica surfaces were investigated using the surface forces apparatus. Friction measurements were made for poly(11-acrylamidoundecanoic acid)-block-poly(alkyl methacrylate)-block-poly(11-acrylamidoundecanoic acid) with an alkyl chain length of C12 (A5L946A5) in the poly(alkyl methacrylate) blocks. The results were compared to those for a PAO solution of a similar triblock copolymer with an alkyl chain length of C18 (A5S992A5) examined in our previous work (Yamada et al., Langmuir 2015). The friction coefficient μ for A5L946A5/PAO was approximately 0.5, which was one or two orders of magnitude larger than that for A5S992A5/PAO (μ of 0.002–0.039). Detailed analysis of the dynamic thickness and contact geometry enabled us to investigate the difference in the friction reduction abilities of the two additives. A5L946A5 has a high affinity to PAO and the molecules have expanded conformation in PAO; extensive chain entanglement effect results in the formation of a thick and viscous lubricant layer, which gives rise to high friction. On the other hand, A5S992A5 has low affinity to PAO, and the shrunken A5S992A5 molecules adsorbed on the surfaces form a rigid slip plane at the interface, which gives rise to low friction. Our results provide insights into the oil/additive combinations used for low friction in oil-based lubrication.

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U2 - 10.1038/s41428-018-0114-y

DO - 10.1038/s41428-018-0114-y

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VL - 51

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JO - Polymer Journal

JF - Polymer Journal

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

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