Influence of air contamination during heat-assisted plasma treatment on adhesion properties of polytetrafluoroethylene (PTFE)

Ohkubo, Yuji; Nakagawa, Toshio; Endo, Kazuhiko; Yamamura, Kazuya

doi:10.1039/c9ra01789e

Cited by 9 publications

(11 citation statements)

References 37 publications

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“…In addition, studies have shown that thermally assisted plasma treatment of PTFE [210,211] can promote the formation of carbon-carbon crosslinks on the surface of PTFE and the etching of weak boundary layers, which greatly improves the adhesion strength of PTFE. Hamdi et al [212] found that when primer coating and UV/ozone radiation were applied, the adhesion of acrylonitrile butadiene styrene increased.…”

Section: Frictionmentioning

confidence: 99%

A review on tribology of polymer composite coatings

et al. 2020

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Self-lubricating polymer composite coatings, with tailorable tribological and mechanical properties, have been widely employed on mechanical parts to reduce friction and wear, which saves energy and improves the overall performance for applications such as aerospace satellite parts, shafts, gears, and bushings. The addition of functional fillers can overcome the limitations of single-polymer coatings and extend the service life of the coatings by providing a combination of low friction, high wear resistance, high load bearing, high temperature resistance, and high adhesion. This paper compares the heat resistance, and the tribological and mechanical properties of common polymer matrices, as well as the categories of functional fillers that improve the coating performance. Applicable scopes, process parameters, advantages, and limitations of the preparation methods of polymer coatings are discussed in detail. The tribological properties of the composite coatings with different matrices and fillers are compared, and the lubrication mechanisms are analyzed. Fillers reduce friction by promoting the formation of transfer films or liquid shear films. Improvement of the mechanical properties of the composite coatings with fillers of different morphologies is described in terms of strengthening and toughening mechanisms, including a stress transfer mechanism, shear yielding, crack bridging, and interfacial debonding. The test and enhancement methods for the adhesion properties between the coating and substrate are discussed. The coating adhesion can be enhanced through mechanical treatment, chemical treatment, and energy treatment of the substrate. Finally, we propose the design strategies for high-performance polymer composite coating systems adapted to specific operating conditions, and the limitations of current polymer composite coating research are identified.

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Section: Frictionmentioning

confidence: 99%

A review on tribology of polymer composite coatings

et al. 2020

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“…The hydrogenation of alkenes takes place during the reaction between the modified surface of PTFE (−C=C−) and ethanol as a transposition of the Billups‐Birch mechanism applied to PTFE in the sodium naphthalenide based diglyme solution. The presence of −C−O and −O−C=O peaks comes from the surface contamination [28] …”

Section: Resultsmentioning

confidence: 99%

Sodium Naphthalenide Diglyme Solution for Etching PTFE, Characterizations and Molecular Modelization

et al. 2022

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Wet etching of polytetrafluoroethylene by sodium naphthalenide dissolved in diglyme solution was investigated experimentally and theoretically. First, the irreversible modification of the polymer surface was analyzed by Raman and XPS spectroscopies, water wetting angle measurements and AFM observations. The drastic changes brought to the surface of PTFE could be clearly demonstrated by these analytical methods. Then, first principle calculations coupled to molecular dynamics (FPMD) were performed to simulate the first steps of the reaction involved in the process of surface modification. It has been shown that fluorine directly attacks vicinal sodium with formation of a pair of sodium fluoride ions without grafting of the naphthalene moiety onto the modified surface. While the formation of the alkene and alkyne bond can be modelized, no spectroscopic signature is observed after rinsing etched PTFE.

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“…The combination of the results of the SEM observation and the surface hardness indicated that the WBL was removed from the He- or Ar-HAP-treated PTFE surface, respectively. It was reported that the surface hardness was 155 MPa when the plasma-treated PTFE surface had neither C–C crosslinks nor the WBL, while the surface hardness was 177 MPa when the plasma-treated PTFE surface had C–C crosslinks but no WBL [ 33 ]. In short, the report demonstrated that the factors that increase the surface hardness include the removal of a WBL and the increase in C–C crosslinks; the removal of a WBL induced an increase of 45 MPa, and the increase in C–C crosslinks induced an increase of 22 MPa in surface hardness.…”

Section: Resultsmentioning

confidence: 99%

“…When a WBL is removed and recovered from PTFE surface via plasma treatment, the PTFE surface hardness increases [ 33 ]. To double-check the presence or absence of a WBL, the surface hardness was measured before and after HAP treatment using a nanoindenter (ENT-2100, Elionix, Hachioji, Tokyo, Japan).…”

Section: Methodsmentioning

confidence: 99%

“…To double-check the presence or absence of a WBL, the surface hardness was measured before and after HAP treatment using a nanoindenter (ENT-2100, Elionix, Hachioji, Tokyo, Japan). The procedure of surface hardness measurement was the same as previously reported [ 33 ]. Load–depth curves were recorded at 20-ms intervals until the maximum load was 40 μN.…”

Section: Methodsmentioning

confidence: 99%

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Effects of He and Ar Heat-Assisted Plasma Treatments on the Adhesion Properties of Polytetrafluoroethylene (PTFE)

et al. 2021

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Heat-assisted plasma (HAP) treatment using He gas is known to improve the adhesive-bonding and adhesive-free adhesion properties of polytetrafluoroethylene (PTFE). In this study, we investigated the effects of He and Ar gaseous species on the HAP-treated PTFE surface. Epoxy (EP) adhesive-coated stainless steel (SUS304) and isobutylene–isoprene rubber (IIR) were used as adherents for the evaluation of the adhesive-bonding and adhesive-free adhesion properties of PTFE. In the case of adhesive bonding, the PTFE/EP-adhesive/SUS304 adhesion strength of the Ar-HAP-treated PTFE was the same as that of the He-HAP-treated PTFE. In the case of adhesive-free adhesion, the PTFE/IIR adhesion strength of the Ar-HAP-treated PTFE was seven times lower than that of the He-HAP-treated PTFE. The relation among gaseous species used in HAP treatment, adhesion properties, peroxy radical density ratio, surface chemical composition, surface modification depth, surface morphology, surface hardness, and the effect of irradiation with vacuum ultraviolet (VUV) and UV photons were investigated. The different adhesive-free adhesion properties obtained by the two treatments resulted from the changes in surface chemical composition, especially the ratios of oxygen-containing functional groups and C–C crosslinks.

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Influence of air contamination during heat-assisted plasma treatment on adhesion properties of polytetrafluoroethylene (PTFE)

Abstract: We show that both applying a high temperature and decreasing the air concentration enhance the adhesion properties of polytetrafluoroethylene to isobutylene–isoprene rubber, but the adhesion properties decrease with increasing the air concentration during treatment.

Cited by 9 publications

References 37 publications

A review on tribology of polymer composite coatings

A review on tribology of polymer composite coatings

Sodium Naphthalenide Diglyme Solution for Etching PTFE, Characterizations and Molecular Modelization

Effects of He and Ar Heat-Assisted Plasma Treatments on the Adhesion Properties of Polytetrafluoroethylene (PTFE)

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