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Research Article
Nicholas D. Spencer
Swiss Federal Institute of Technology
Corresponding Author
ORCiD: https://orcid.org/0000-0002-7873-7905
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In the search for new, oil-compatible friction-modifier additives that can significantly reduce energy consumption by reducing the friction in the boundary-lubrication regime, a macromolecular-design approach has been taken. This involved the synthesis of a series of readily functionalizable block copolymers carrying an oleophilic poly(lauryl methacrylate) block and a functionalizable poly(pentafluorophenyl methacrylate) block of various lengths by means of reversible addition-fragmentation chain-transfer (RAFT) polymerization. The poly(pentafluorophenyl methacrylate) block was used to attach surface-active nitro-catechol anchoring groups to the polymer. The friction-reduction properties of these polymers were assessed using 0.5 wt.% solutions in hexadecane using rolling-sliding macroscopic tribological tests. Block copolymers with roughly equal block lengths and moderate molecular weights were significantly more effective at friction reduction than all other architectures investigated. They also displayed lower friction coefficients than glycerol monooleate, a commercially used additive. The film formation ability of these polymers was examined using a quartz-crystal microbalance with dissipation (QCM-D), by monitoring their adsorption onto an iron-oxide coated QCM crystal. The polymer with highest lubrication efficiency formed a thin film of ∼17 nm thickness on the iron-oxide coated QCM crystal, consistent with the formation of a polymer brush. Interferometric rolling-sliding experiments with the same polymer showed a separating film thickness of ∼20 nm, which is consistent with the QCM-D value, bearing in mind the compression of the adsorbed layers on the two sliding surfaces during tribological testing.
Keywords
lubricant additive, friction-reduction, RAFT polymerization, block-copolymer, oil-compatibility
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CURRENT STATUS: Published
View the published article at Tribology Letters.
Version 1
Posted 10 Jun, 2021
No community comments so far
Editorial decision: Major Revisions Needed
On 05 Jul, 2021
Reviews received
Received 07 Jun, 2021
Reviewers invited
Invitations sent on 04 Jun, 2021
Editor assigned
On 03 Jun, 2021
First submitted
On 02 Jun, 2021
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Subject Areas
Polymer Science
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See the published version of this preprint at Tribology Letters.
This is a preprint, a preliminary version of a manuscript that has not completed peer review at a journal. Research Square does not conduct peer review prior to posting preprints. The posting of a preprint on this server should not be interpreted as an endorsement of its validity or suitability for dissemination as established information or for guiding clinical practice.
Learn more about In Review
Research Article
Nicholas D. Spencer
Swiss Federal Institute of Technology
Corresponding Author
ORCiD: https://orcid.org/0000-0002-7873-7905
Badges
Prescreen
This manuscript passed our Prescreen assessment
Complete author information
Appropriate declaration statements
Potential risks to human health
Prescreen
Peer Review Timeline
CURRENT STATUS: Published
View the published article at Tribology Letters.
Version 1
Posted 10 Jun, 2021
No community comments so far
Editorial decision: Major Revisions Needed
On 05 Jul, 2021
Reviews received
Received 07 Jun, 2021
Reviewers invited
Invitations sent on 04 Jun, 2021
Editor assigned
On 03 Jun, 2021
First submitted
On 02 Jun, 2021
Metrics
Comments: 0
PDF Downloads: ...
HTML Views: ...
Subject Areas
Polymer Science
License:
This work is licensed under a CC BY 4.0 License. Read Full License
View the published article at Tribology Letters.
In the search for new, oil-compatible friction-modifier additives that can significantly reduce energy consumption by reducing the friction in the boundary-lubrication regime, a macromolecular-design approach has been taken. This involved the synthesis of a series of readily functionalizable block copolymers carrying an oleophilic poly(lauryl methacrylate) block and a functionalizable poly(pentafluorophenyl methacrylate) block of various lengths by means of reversible addition-fragmentation chain-transfer (RAFT) polymerization. The poly(pentafluorophenyl methacrylate) block was used to attach surface-active nitro-catechol anchoring groups to the polymer. The friction-reduction properties of these polymers were assessed using 0.5 wt.% solutions in hexadecane using rolling-sliding macroscopic tribological tests. Block copolymers with roughly equal block lengths and moderate molecular weights were significantly more effective at friction reduction than all other architectures investigated. They also displayed lower friction coefficients than glycerol monooleate, a commercially used additive. The film formation ability of these polymers was examined using a quartz-crystal microbalance with dissipation (QCM-D), by monitoring their adsorption onto an iron-oxide coated QCM crystal. The polymer with highest lubrication efficiency formed a thin film of ∼17 nm thickness on the iron-oxide coated QCM crystal, consistent with the formation of a polymer brush. Interferometric rolling-sliding experiments with the same polymer showed a separating film thickness of ∼20 nm, which is consistent with the QCM-D value, bearing in mind the compression of the adsorbed layers on the two sliding surfaces during tribological testing.
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
This is a list of supplementary files associated with this preprint. Click to download.
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