Oleophobization

Polyfluorinated chemicals now dominate in the fields of oil-repellent and water-repellent finishes. The earlier so-called conventional polyfluorinated products were of the type represented by poly(N-methylperfluoro-octanesulphonamidoethyl acrylate) (10.248) [499]. Such products presented a shield of closely packed fluoroalkyl groups at the fibre-air interface, thus giving low-energy surfaces with excellent oleophobicity. These showed excellent resistance to oil-based stains but were less satisfactory as soil-release agents during... 

Sagiv J (1980) Organized monolayers by adsorption. 1. Formation and structure of oleophobic mixed monolayers on solid surfaces. J Am Chem Soc 102 92-98... 

Figure 4.24 Dynasylan SIVO 121 forms an almost invisible protective layer (top). On untreated wood surfaces and surfaces that are weathered and varnished, Dynasylan SIVO 121 produces a strong hydrophobic and oleophobic effect. (Reproduced from Dynasylan.com)...

Several classes of polymers including epoxies have been developed from 2-phenyl-l,l,l,3,3,3-hexafluoropropan-2-ol and its derivatives.1 Fluorinated epoxy resins are the key intermediates for the new types ofpractical organic coatings and plastics, which have fluorocarbon properties and convenient characteristics such as hydrophobicity, oleophobicity, light stability, low friction, and, in some cases, possibly high thermal stability. 

Oleophobic. Compounds that have a strong repulsion to oils. 

Problems have also been observed at resist coat due to substrate nonwetting or oleophobicity. This problem is independent of the more commonly occurring pattern lifting (see Fig. 3 for examples of missing or displaced images) adhesion failure problem, which is observed after resist exposure and development. We will also focus on work addressing these latter two specific problem areas in this paper. 

For many organic compounds that accumulate in lipids, bio accumulation potential can be estimated from the Kow. Since perfluoroalkyl compounds are inherently oleophobic, and do not partition preferentially to lipid rich tissues [67], the K0w is not a useful predictor of bioaccumulation and direct evidence derived from the laboratory or field is required. Additionally, tissue concentrations of perfluoroalkyl substances should never be lipid normalized. The dietary accumulation, bioconcentration, and biomagnification potential of various perfluoroalkyl carboxylates and sulfonates have been assessed in the laboratory and in the Great Lakes food web (Table 4). 

The concentrations of PFAs in environments have increased sharply over time (Holmstrom et al., 2005). The sorption/accumulation and fate of PFAs differ from classical chlorinated and brominated POPs in that perfluorinated molecules have surfactant characteristics (i.e., having polar and nonpolar domains) and oleophobic properties. Thus, PFAs is likely to bind to serum protein rather than lipid in tissues (Jones et al., 2003). 

A qualitative term referring to the water-preferring nature of a species (atom, molecule, droplet, particle). For emulsions, hydrophilic usually means that a species exhibits an affinity for the aqueous phase over the oil phase. In this example, hydrophilic has the same meaning as oleophobic, but such is not always the case. 

The (usually fatty) organic-liquid-avoiding nature of a species. Depending on the circumstances can also be a synonym for oleophobic . 

The perfluoroalkyl diols 12 exhibit good hydrophobic and oleophobic properties. For instance, they are used for treating porous (paper, wood, leather, fibers, textiles) or non porous materials (surfaces of glass, metals or synthetic products). 

W. C. Bigelow, D. L. Pickett, and W. A. Zisman, Oleophobic monolayers. I. Films adsorbed from solution in nonpolar liquids,. Colloid Sci. 1 513-538 (1946). 

Adsorbed films of ethykriethoxysilane and vinyltriethoxy-silane were formed on silica and alumina by retraction from hydrocarbon solution and their wettabilities and water-stabilities determined. The vinyltriethoxysilane films were generally more oleophobic, more hydrophobic and more resistant to contact with water than the films formed by the ethyl analog. Neither adsorbate formed stable films on a-alumina. The addition of low molecular weight organic acids or bases to the adsorbate solution resulted in both the ethyl and vinyl compound forming hydrophobic and water-stable films on silica and ot-alumina. Films of p-chloro-phenyl-ft-ethyltrichloro, -trimethoxy, and -triethoxysilane were also studied and found to be water-stable and to have wettabilities characteristic of a surface comprised of closely-spaced p-chlorophenyl groups. 

The present paper describes the adsorption of ethyltriethoxysilane (ETES) and vinyltriethoxysilane (VTES) at various organic-liquid/silica interfaces. Films formed by these compounds on silica and glass from solution in nonpolar organic liquids were found to be oleophobic and so could be isolated by retraction that is, the substrate on which the films had been formed emerged dry from the solution, thus allowing direct examination of the adsorbed layer. 

Vinyl triethoxy silane (VTES). The vinyltriethoxy silane films obtained on silica were more oleophobic (lower y0 values) and more hydrophobic (higher 0H2o values) than the films formed from corre-... 

The contention that polymer adsorption can result in oleophobic (low yc ) and water stable films is given support by the results using the ETES polymer-monomer solution (Figure 10). In this case preformed polymer was present in the solution along with the monomer ETES, and the resulting films had a wettability not unlike those formed by the 1% and 5% VTES solutions on flamed silica. The water stability of these films can be explained by a film structure that is predominately polymer units. Desorption then requires the simultaneous breaking of many bonds which is a statistically unlikely event. 

Bigelow WC, Pickett DL et al (1946) Oleophobic monolayers. 1 - Films adsorbed from solution in non-polar liquids. J Colloid Sci 1 513-538... 

Finally, the hydrophobic character of a polymeric material can be estimated from contact angle measurements of a water drop deposited on its surface, the values of the contact angle depending on the chemical composition of the surface. Fluorinated polymers having good hydrophobic and oleophobic properties and... 

Vapor deposition has been used to prepare fibers such as woven and nonwoven synthetic and natural fibers having hydrophobic/oleophobic and biocide properties. This process entails flash evaporation of a perfluoroacrylate monomer and its radiation curing in a vacuum chamber onto a selected fiber surface. 

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