Handle URI:
http://hdl.handle.net/10754/598655
Title:
Interfacial Friction and Adhesion of Polymer Brushes
Authors:
Landherr, Lucas J. T.; Cohen, Claude; Agarwal, Praveen; Archer, Lynden A.
Abstract:
A bead-probe lateral force microscopy (LFM) technique is used to characterize the interfacial friction and adhesion properties of polymer brushes. Our measurements attempt to relate the physical structure and chemical characteristics of the brush to their properties as thin-film, tethered lubricants. Brushes are synthesized at several chain lengths and surface coverages from polymer chains of polydimethylsiloxane (PDMS), polystyrene (PS), and a poly(propylene glycol)-poly(ethylene glycol) block copolymer (PPG/PEG). At high surface coverage, PDMS brushes manifest friction coefficients (COFs) that are among the lowest recorded for a dry lubricant film (μ ≈ 0.0024) and close to 1 order of magnitude lower than the COF of a bare silicon surface. Brushes synthesized from higher molar mass chains exhibit higher friction forces than those created using lower molar mass polymers. Increased grafting density of chains in the brush significantly reduces the COF by creating a uniform surface of stretched chains with a decreased surface viscosity. Brushes with lower surface tension and interfacial shear stresses manifest the lowest COF. In particular, PDMS chains exhibit COFs lower than PS by a factor of 3.7 and lower than PPG/PEG by a factor of 4.7. A scaling analysis conducted on the surface coverage (δ) in relation to the fraction (ε) of the friction force developing from adhesion predicts a universal relation ε ∼ δ4/3, which is supported by our experimental data. © 2011 American Chemical Society.
Citation:
Landherr LJT, Cohen C, Agarwal P, Archer LA (2011) Interfacial Friction and Adhesion of Polymer Brushes. Langmuir 27: 9387–9395. Available: http://dx.doi.org/10.1021/la201396m.
Publisher:
American Chemical Society (ACS)
Journal:
Langmuir
KAUST Grant Number:
KUS-C1-018-02
Issue Date:
2-Aug-2011
DOI:
10.1021/la201396m
PubMed ID:
21696203
Type:
Article
ISSN:
0743-7463; 1520-5827
Sponsors:
Support from Award No. KUS-C1-018-02 made by King Abdullah University of Science and Technology (KAUST) and from the National Science Foundation Polymers Program (Grant DMR- 0705565) is gratefully acknowledged. The AFM sliding friction measurements were performed using facilities of the Cornell Center for Materials Research (CCMR), a Materials Research Science and Engineering Center of the National Science Foundation (DMR-0520404).
Appears in Collections:
Publications Acknowledging KAUST Support

Full metadata record

DC FieldValue Language
dc.contributor.authorLandherr, Lucas J. T.en
dc.contributor.authorCohen, Claudeen
dc.contributor.authorAgarwal, Praveenen
dc.contributor.authorArcher, Lynden A.en
dc.date.accessioned2016-02-25T13:33:53Zen
dc.date.available2016-02-25T13:33:53Zen
dc.date.issued2011-08-02en
dc.identifier.citationLandherr LJT, Cohen C, Agarwal P, Archer LA (2011) Interfacial Friction and Adhesion of Polymer Brushes. Langmuir 27: 9387–9395. Available: http://dx.doi.org/10.1021/la201396m.en
dc.identifier.issn0743-7463en
dc.identifier.issn1520-5827en
dc.identifier.pmid21696203en
dc.identifier.doi10.1021/la201396men
dc.identifier.urihttp://hdl.handle.net/10754/598655en
dc.description.abstractA bead-probe lateral force microscopy (LFM) technique is used to characterize the interfacial friction and adhesion properties of polymer brushes. Our measurements attempt to relate the physical structure and chemical characteristics of the brush to their properties as thin-film, tethered lubricants. Brushes are synthesized at several chain lengths and surface coverages from polymer chains of polydimethylsiloxane (PDMS), polystyrene (PS), and a poly(propylene glycol)-poly(ethylene glycol) block copolymer (PPG/PEG). At high surface coverage, PDMS brushes manifest friction coefficients (COFs) that are among the lowest recorded for a dry lubricant film (μ ≈ 0.0024) and close to 1 order of magnitude lower than the COF of a bare silicon surface. Brushes synthesized from higher molar mass chains exhibit higher friction forces than those created using lower molar mass polymers. Increased grafting density of chains in the brush significantly reduces the COF by creating a uniform surface of stretched chains with a decreased surface viscosity. Brushes with lower surface tension and interfacial shear stresses manifest the lowest COF. In particular, PDMS chains exhibit COFs lower than PS by a factor of 3.7 and lower than PPG/PEG by a factor of 4.7. A scaling analysis conducted on the surface coverage (δ) in relation to the fraction (ε) of the friction force developing from adhesion predicts a universal relation ε ∼ δ4/3, which is supported by our experimental data. © 2011 American Chemical Society.en
dc.description.sponsorshipSupport from Award No. KUS-C1-018-02 made by King Abdullah University of Science and Technology (KAUST) and from the National Science Foundation Polymers Program (Grant DMR- 0705565) is gratefully acknowledged. The AFM sliding friction measurements were performed using facilities of the Cornell Center for Materials Research (CCMR), a Materials Research Science and Engineering Center of the National Science Foundation (DMR-0520404).en
dc.publisherAmerican Chemical Society (ACS)en
dc.titleInterfacial Friction and Adhesion of Polymer Brushesen
dc.typeArticleen
dc.identifier.journalLangmuiren
dc.contributor.institutionCornell University, Ithaca, United Statesen
kaust.grant.numberKUS-C1-018-02en

Related articles on PubMed

All Items in KAUST are protected by copyright, with all rights reserved, unless otherwise indicated.