Chromatic polymers

Orynbayeva Z, Kolusheva S, Livneh E, Lichtenshtein A, Nathan I, Jehnek R. Visuahzation of membrane processes in hving cells by surface-attached chromatic polymer patches. Angew Chem Int Ed 2005 44 1092-1096. 

Shtelman E, Tomer A, Kolusheva S, Jelinek R. Imaging membrane processes in erythrocyte ghosts by surface fusion of a chromatic polymer. Anal Biochem 2006 348 151-153. 

FIGURE 8.7 Chromatic polymers and applications of electrochromic devices based on electrothermal chromatic... 

It is interesting to note that the two earliest imaging materials involved in the initial photolytic step of their imaging systems, namely silver halides and di-chromated polymers are the only ones remaining in commercial use in any real sense. All the others have come and gone including the once important, iron-based blueprints. It is therefore curious that neither silver, chromium or iron had a high profile in the academic discipline of photochemistry. Calvert and Pitts [58], one of the most widely used textbooks on photochemistry in the late twentieth century, barely mentions them at aU. 

The compositions of the conversion baths are proprietary and vary greatly. They may contain either hexavalent or trivalent chromium (179,180), but baths containing both Cr(III) and Cr(VI) are rare. The mechanism of film formation for hexavalent baths has been studied (181,182), and it appears that the strength of the acid and its identity, as well as time and temperature, influences the film s thickness and its final properties, eg, color. The newly prepared film is a very soft, easily damaged gel, but when allowed to age, the film slowly hardens, assumes a hydrophobic character and becomes resistant to abrasion. The film s stmcture can be described as a cross-linked Cr(III) polymer, that uses anion species to link chromium centers. These anions may be hydroxide, chromate, fluoride, and/or others, depending on the composition of the bath (183). 

Mechanical and Chemical Properties. Colorants, especially pigments, can affect the tensile, compressive, elongation, stress, and impact properties of a polymer (5). The colorants can act as an interstitial medium and cause microcracks to form in the polymer colorant matrix. This then leads to degradation of the physical properties of the system. Certain chemicals can attack colorants and there can be a loss of physical properties as well as a loss of the chromatic attributes of the colorant. Colorants should always be evaluated in the resin in which they will be used to check for loss of properties that ate needed for the particular appHcations. 

See also Axial dispersion aerosols, 1 774-775 aqueous, 18 292 behavior of, 15 685-690 chemical processing aids, 8 705-711 chromatic, 11 134 classification, 8 698-699 colorants for plastics, 7 360-361 donor-acceptor interactions, 8 707-708 electrostatic repulsion, 8 732-734 in filled networks, 22 572 of filled polymers, 11 307-308 flow, 8 726-730 flushing, 8 711... 

Morpholine chromate, molecular formula, properties, and uses, 6 562t Morphology. See also Structure of carbon fibers, 26 737-739 of high density polyethylene, 20 162 of polymer blends, 20 356 of polymer colloid, 20 386-388 of PVC particles, 25 658-661, 661-663, 664-665... 

The influence of the nature of the polymer support on the oxidation power of complex chromates was investigated by T. Brunelet, C. Jouitteau, G. Gelbard, /. Org. Chem. 1986, 53, 4016-4022. 

Almost all aluminum structures are painted with organic polymers for corrosion protection. The purpose of incorporating an inhibitor interface (chromate conversion coating) between the substrate and tlie paint film is to ensure protection vAien paints fail to perform( ). It has been generally acc ted that no matter what Icind of paint system, and how well it is applied, it always will have some porosity defects and will degrade with tine during service. 

Oxidation of alcohols to aldehydes or ketones is accomplished with chromate bound to an anion-exhange resin (XXXIX with A = HC1O4 ) [Frechet et al., 1981 Taylor, 1986]. Other oxidants include polymers functionalized with CIO-, CICr04, and RuOj [Kirschning et al.,... 

Polymers of thiophene carboxylic acids (9) undergo different chromatic transitions upon the addition of a variety of cations (McCullough et al. 1997). Although the acid form of the polymer was not water soluble, addition of various ammonium or metal... 

Polythiophenes functionalized with monosaccharides have been evaluated for their ability to detect the influenza virus and E. coli (Baek et al. 2000). Copolymers of thiophene acetic acid 10 and carbohydrate-modified thiophenes 11 have been prepared via iron(III) chloride mediated polymerization. Addition of influenza virus to a sialic acid containing copolymer resulted in a blue shift of the polymer absorption maximum, resulting in an orange to red chromatic transition. Mannose-containing polythiophenes underwent color changes upon the addition of the lectin ConA or E. coli cells that contain cell surface mannose-binding receptors. A similar biotinylated pol5hhiophene afforded a streptavidin responsive material (Paid and Leclerc 1996). 

Silbert L, Ben Shlush I, Israel E, Porgador A, Kolusheva S, Jelinek R. Rapid chromatic detection of bacteria by use of a new biomimetic polymer sensor. Appl Environ Microbiol 2006 72 7339-7344. 

Song J, Cheng Q, Kopta S, Stevens RC. Modulating artificial membrane morphology pH-induced chromatic transition and nanostructural transformation of a bolaamphiphilic conjugated polymer from blue helical ribbons to red nanofibers. J Am Chem Soc... 

Pyridinium and quaternary ammonium resins react with chromium trioxide, producing polymer-supported complex chromates that oxidize alcohols, and provide a very facile work-up.427... 

Higher pH chromate programs (pH 7.0 to 9.0), using chromate (3 to 15 ppm) with P04 (3 to 6 ppm) and/or Zn (0.5 to 2.5 ppm). Phosphonate/polymer support is required, the selection of which permits progressively lower chrome levels and higher cooling water pH. 

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