Non-adhesiveness

PTFE is used for lining chutes and coating other metal objects where low coefficients of friction or non-adhesive characteristics are required. Because of its excellent flexing resistance, inner linings made from dispersion polymer are used in flexible steam hose. A variety of mouldings are used in aircraft and missiles and also in other applications where use at elevated temperatures is required. 

The commercial polymers are mechanically similar to PTFE but with a somewhat greater impact strength. They also have the same excellent electrical insulation properties and chemical inertness. Weathering tests in Florida showed no change in properties after four years. The material also shows exceptional non-adhesiveness. The coefficient of friction of the resin is low but somewhat higher than that of PTFE. Films up to 0.010 in thick show good transparency. 

The rubbers are also used for such diverse applications as blood transfusion tubing capable of sterilisation, antibiotic container closures, electric iron gaskets, domestic refrigerators and non-adhesive rubber-covered rollers for handling such materials as confectionery and adhesive tape. The cold-curing rubbers are of value in potting and encapsulation. 

Viscoelastic contact problems have drawn the attention of researchers for some time [2,3,104,105]. The mathematical peculiarity of these problems is their time-dependent boundaries. This has limited the ability to quantify the boundary value contact problems by the tools used in elasticity. The normal displacement (u) and pressure (p) fields in the contact region for non-adhesive contact of viscoelastic materials are obtained by a self-consistent solution to the governing singular integral equation given by [106] ... 

The glass-ionomer cement is the most versatile of all the dental cements and has been developed for a variety of applications (McLean Wilson, 1974, 1977a,b,c Swift, 1988b van de Voorde, 1988 Wilson McLean, 1988 Mount, 1990). Many of its applications depend on its adhesive quality which means that, unlike the non-adhesive traditional filling materials, it does not require the preparation of mechanical undercuts for retention and the consequent loss of sound tooth material. 

Hancox, L. S., Yeh, K. S., and Clegg, S. (1997). Construction and characterization of type 1 non-fimbriate and non-adhesive mutants of Salmonella typhimurium. EEMS Immunol. Med. Microbiol. 19, 289-296. 

Note that many of these surface reactions involve the conversion of a hydrophophic polymer to one with a hydrophilic surface or vice versa. For example, the replacement of trifluoroethoxy groups at the interface by hydroxyl units changes a non-adhesive, highly hydrophobic surface to an adhesive hydrophilic one. Variations in the reaction conditions allow both the depth of transformation and the ratios of the initial to the new surface groups to be controlled. A possible complication that needs to be kept in mind for all of these surface transformations is that polymer molecular motions may bury the newly introduced functional units if the polymer comes into contact with certain media. For example, a hydrophilic surface on a hydrophobic polymer may become buried when that surface is exposed to dry air or a hydrophobic liquid. But this process can be reversed by exposure to a hydrophilic liquid. 

Tirosh, B., and A. Rubinstein. 1998. Migration of adhesive and non-adhesive particles in the rat intestine under altered mucus secretion conditions. J Pharm Sci 87 453. 

Adherent cells have also been patterned using cell-adhesive and non-cell-adhesive microdomains created on a glass coverslip. This coverslip was then bonded with a PDMS channel layer for cell patterning [857]. For instance, endothelia or astrocyte-neuron cocultures were plated only on the cell-adhesive poly-L-lysine microdomains, but not on the non-adhesive agarose (1%) microdomains. Subsequently, calcium wave measurements were made to study calcium signaling of cells in two modes (1) within confluent cell microdomains, and (2) across neighboring, but spatially disconnected, microdomains [857]. 

Takahashi H, Emoto K, Dubey M et al (2008) Imaging surface immobilization chemistry correlation with cell patterning on non-adhesive hydrogel thin films. Adv Funct Mater 18(14) 2079-2088... 

The occurrence of either partial slip or gross slip condition is dependent on the material mechanical properties, the magnitude of the coefficient of friction and the contact loading parameters (normal load, imposed displacement). When dealing with non-adhesive elastic materials, the effects of these... 

Combination of metal to be deposited with water repellent powder. In composite plating, the characteristics of particles to be codeposited are the most important. Water repellent fluoroplastic powder represented by Polytetrafluoro-ethylene (PTFE) has various unique and interesting characteristics such as non-adhesiveness, self-lubricity and chemical resistance, as well as water repellency. Incorporation of such powder into the composite plating would give a surface with quite different characteristics from those obtained by conventional surface treatments. Representative water repellent powders used in this study of composite plating are graphite fluoride [(CF) ] and PTFE. 

Another potential application of the cell-imprinted polymers is the manufacture of tailor-made substrata for the cultivation of animal cells. These can be prepared either in the form of beads or planar surfaces, analogous perhaps to Petri dishes but containing discrete cell nests , separated by a layer of non-adhesive polymer to prevent contact between the cells (Fig. 11.6). 

Powder formulations for capsule filling must have good flow properties, be non-adhesive, and be cohesive enough to form plugs at low-compression forces. In addition, they must be stable and release the active ingredient in the desired manner. There is an interaction between the formulation, the filling machine, and the empty capsules, and to devise formulations logically, these need to be understood. 

Foaming the polymer creates small, open cells that are able to hold fluids and the cell size may be controlled during the foaming process. The most common polymer used is polyurethane. Their structure and softness also provide a cushion that protects and contributes to thermal insulation of the wound. They also may be tailored for particular applications such as tracheostomy dressing without particle loss to the wound and with the retention of their conformable characteristics. The non-adhesive foams will require a secondary dressing. 

The extrudate must be non-adhesive to itself in order that each spherical granule remains discrete throughout the process. 

For an adhesive to be successful it must compete with non-adhesive joining techniques such as welding, nuts and bolts, rivets and staples. Modern adhesive joining can be used to replace or supplement traditional joining methods only when the quality, performance and economics are acceptable. 

Holland, N.B. Qiu, Y. Ruegsegger, M. Marchant, R.E. Biomimetic engineering of non-adhesive glycocalyx-like surfaces using oligosaccharide surfactant polymers. Nature 1998, 392 (6678), 799-801. 

The adhesiveness of the stranded oil varies with the type of oil and the degree of weathering. Most fresh oils are not highly adhesive, whereas weathered oils often are. Diesel and gasoline are relatively non-adhesive, crudes are generally moderately adhesive when fresh and adhesive when weathered, and Bunker C is adhesive when fresh and highly adhesive when weathered. An oil that is not adhesive when it reaches the shore may get washed off, at least partially, on the next tidal cycle. 

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