Surface diffusion and flow activation energies of perfluoropolyalkylether

O’Connor, Teresa; Jhon, Myung S.; Bauer, Charles L.; Min, Byoung‐Chul; Yoon, Do Y.; Karis, T. E.

doi:10.1007/bf00209776

Cited by 55 publications

(42 citation statements)

References 2 publications

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“…The spreading profiles of PFPE Z on an amorphous carbon surface, shown in Fig. 3, were measured via SME (10,11). To extract the surface diffusion coefficients, the Matano interface method (11,12), which extracts the thicknessdependent diffusion coefficient directly from the spreading film profile, was employed.…”

Section: Resultsmentioning

confidence: 99%

“…Novotny's findings indicate that the surface diffusion coefficient increased as the film thickness decreased down to 1 nm and was constant below this thickness. The spreading characteristics of PFPEs on silica and carbon surfaces have been investigated via SME as a function of initial film thickness, endgroup functionality, molecular weight, temperature, and humidity by O'Connor et al (10) and Ma et al (11,12). Ma et al extracted surface diffusion coefficients from the spreading profiles by employing the Matano interface method.…”

Section: Introductionmentioning

confidence: 99%

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The Molecular Spreading of Nonpolar Perfluoropolyether Films on Amorphous Carbon Surfaces

Kim

Phillips

2000

Journal of Colloid and Interface Science

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Molecular Spreading of Nonpolar Perfluoropolyether Films on Amorphous Carbon Surfaces

Kim

Phillips

2000

Journal of Colloid and Interface Science

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“…Typical SME thickness profiles for monodisperse Z and Zdol, as analyzed by O'Connor et al [6,7], are shown in figure 1 (a) and (b). As the film spreads with time, the spreading front travels along the surface of the silicon wafers.…”

Section: Scanning Microellipsometrymentioning

confidence: 98%

“…In the experiments of O'Connor et al [7], monodisperse fractions of PFPE Z and Zdol, which were fractionated via supercritical fluid extraction in CO 2 , were dip-coated onto the surface of silicon wafers.…”

Section: Scanning Microellipsometrymentioning

confidence: 99%

“…He found that the surface diffusion coefficient increased as the film thickness decreased down to 1 nm and remained constant below that thickness. Subsequent investigations focused on the effects of initial film thickness, endgroup functionality, molecular weight, relative humidity, and temperature for silica surfaces were performed by Min et al [6] and O'Connor et al [7] and for amorphous carbon surfaces were conducted by Ma et al [8,9].…”

Section: Introductionmentioning

confidence: 99%

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Spreading and dewetting in nanoscale lubrication

Karis

Kim

2005

Tribol Lett

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This article critically reviews the fundamental scientific tools, as well as constructs cohesive schemes for potential applications, relevant to the molecularly-thin liquid film technology. Our focus is to understand the nanoscale dynamic behavior of thin lubricant films, relevant to the emerging field of nanotechnology, especially for achieving durability and reliability in the nanoscale devices. Our goal is to present a unified and hybrid description of perfluoropolyether (PFPE) experiment, mesoscopic interpretation, microscopic simulation tools, and molecular design tools available up to now. The experimentation and theory for the physicochemical properties of ultra-thin PFPE films are used to examine liquid film in the sub-monolayer to multilayer regime. Methods for extracting spreading properties from the scanning microellipsometry (SME) for various PFPE/solid surface pairs and the surface rheological characterization of PFPEs are examined. The interrelationships among SME spreading profiles, rheology, surface energy, and tribology, are given. Mesoscopic theories, including thermodynamics of evaporation and flow, stability analysis, microscale mass transfer, and capillary waves are introduced to describe thin PFPE film dynamics. Estimation of thin film viscosity enhancement from vapor pressure suppression by dispersion force is reviewed. The method for experimental derivation of lubricant spreading profiles from contact angles is summarized. The implications of capillary waves, or thermal fluctuations, at the surface of polymeric lubricant films are also discussed. The lattice-based, simple reactive sphere Monte Carlo (MC) technique for examining the fundamentals of PFPE dynamics is illustrated. An off-lattice based bead-spring MC model is also introduced to capture a detailed internal structure of the PFPE molecules, and the molecular dynamics method is implemented for a full-scale nanostructural analysis of PFPE ultra-thin films. By systematically tuning the endgroup strengths of PFPE, we examined the physicochemical properties for thin liquid films of the various PFPE/solid surface pairings. These tools accurately describe the static and dynamic behavior of ultra-thin liquid films consistent with experimental findings and thus are suitable for examining the fundamental mechanisms of lubrication in nanoscale devices. Application of the next generation head-disk interface design in information storage device is briefly considered.

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Physicochemical Properties of Nanostructured Perfluoropolyether Films

Jhon

2004

Advances in Chemical Physics

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Surface diffusion and flow activation energies of perfluoropolyalkylether

Cited by 55 publications

References 2 publications

The Molecular Spreading of Nonpolar Perfluoropolyether Films on Amorphous Carbon Surfaces

The Molecular Spreading of Nonpolar Perfluoropolyether Films on Amorphous Carbon Surfaces

Spreading and dewetting in nanoscale lubrication

Physicochemical Properties of Nanostructured Perfluoropolyether Films

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