Perfluoropolyethers coatings

Saunders, A.E., Shah, P.S., Park, E.J., Lim, K.T., Johnston, K.P. and Korgel, B.A. (2004) Solvent density-dependent steric stabilization of perfluoropolyether-coated nanocrystals in supercritical carbon dioxide. Journal of Physical Chemistry B, 108 (41), 15969-15975. 

Chernyak Y, Henon F, Harris RB, Gould RD, Franklin RK, Edwards JR, DeSimone JM, Carbonell RG. Formation of perfluoropolyether coatings by the rapid expansion of supercritical solutions (RESS) process. 1. Experimental results. Ind Eng Chem Res 2001 40 6118-6126. 

Guney-Altay, 0., Levit, N., Pestov, D., Tepper, G. (2006). Precipitation of nanocomposite particles from a multi-component, rapidly expanding supercritical solution,/. Supercrit Fluids, 27,229-241. Chernyak, Y, Henon, F., Harris, R. B., Gould, R. D., Franklin, R K., Edwards J. R, De Simone, J. M., Carbonell, R G. (2001). Formation of perfluoropolyether coatings by the rapid expansion of supercritical solutions (RESS) process. Part 1. Experimental results, Ind. Eng. Chem. Res., 40,6118-6126. 

MECHANISM OF PHOTOSTABILIZATION OF PERFLUOROPOLYETHER COATINGS BY HINDERED AMINE STABILISERS... 

Example 11.4. McGuiggan et al. [492] measured the friction on mica surfaces coated with thin films of either perfluoropolyether (PFPE) or polydimethylsiloxane (PDMS) using three different methods The surface forces apparatus (radius of curvature of the contacting bodies R 1 cm) friction force microscopy with a sharp AFM tip (R 20 nm) and friction force microscopy with a colloidal probe (R 15 nm). In the surface force apparatus, friction coefficients of the two materials differed by a factor of 100 whereas for the AFM silicon nitride tip, the friction coefficient for both materials was the same. When the colloidal probe technique was used, the friction coefficients differed by a factor of 4. This can be explained by the fact that, in friction force experiments, the contact pressures are much higher. This leads to a complete penetration of the AFM tip through the lubrication layer, rendering the lubricants ineffective. In the case of the colloidal probe the contact pressure is reduced and the lubrication layer cannot be displaced completely. 

Standard computer hard disk surfaces (substrates used in this experiment were industrial hard disk surfaces that have been sputter-coated with nominally 100 A of hydrogenated amorphous carbon) can be coated by dip coating with nm thin films of perfluoropolyethers, such as Fomblin ZDOL, from solutions in perfluorohexane. For films thicker than several nm dewetting occurs spontaneously over a period of days to weeks due to the autophobic effect [43]. 

A facile method by which organic thin films may be readily coated upon substrates employs the electron beam curing of materials such as of monomeric and/or oligomeric acrylates and methacrylates. The perfluorinated acrylates 2-(N-butylperfluorooctanesulfonamido)ethyl acrylate (BFOSA), 2-(N-ethylperfluorooctanesulfonamido)ethyl acrylate (EFOSA), and perfluoropolyether diacrylate (PFEDA) were obtained from the 3M corporation, St. Paul, Minnesota 1,6-Hexanediol diacrylatc (HDODA) was obtained from Interez, Inc., Louisville, Kentucky. 

The application of the cyclophosphazene N3P3(OC6H4F-4) (OC6H4CF3-3)e (n 2 code name X-IP) as a lubricant is well known. Comparative studies of the tribological properties of X-IP and ionic liquids of al-kylimidazolium tetrafluoroborates have shown a preference for the tetrafluo-roborates as lubricants. The interaction of X-IP with a carbon-coated head at the head-disk interface of hard disk magnetic storage systems in the presence of a perfluoropolyether (PFPE) lubricant, has been diseussed. Attention has been paid to the application of a novel lubricant (A20H) which consists of (234) as the major component and small quantities of (235). The new lubricant displays a lower mobility on carbon surfaces than hydroxyl-... 

Polytetrafluoroethylene coatings deposited together with boron nitride by radiofrequency sputtering are applied to molded rubber parts in order to reduce their dynamic friction [27] the same holds true for perfluoropolyether compositions [28]. 

Recent work by lacono et al. [16], employed perfluoropolyethers (PFPEs) to coat nano-aluminum particles. The nonvolatility and viscous characteristic of PFPEs make them ideal oxidizers and aid greatly in maximizing surface interactions. These coated Al particles are used in the production of an energetic Al -i- PFPE epoxy composite that experiences latent thermal metal-mediated oxidation. This powder... 

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