Conformation Cross linked poly

A similar photo-effect on the swelling of cross-linked poly(methacrylic acid) (PMA) was observed in the presence of 4-phenylazophenyl trimethylammonium ions (J9) [38]. An increased cis content of the chromophore by photoirradiation at a pH in the range of conformation unfolding of PMA led to an increased ionization and thus enhanced swelling. The conversion efficiency of light energy to mechanical work was calculated to be 3 x 10 . ... 

Temperature dependence (related to the temperature dependence of the conformational structure and the morphology of polymers) of the radiation effect on various fluoropolymers e.g., poly (tetrafluoroethylene-co-hexafluoropropylene), poly(tetrafluoroethylene-co-perfluoroalkylvinylether), and poly(tetrafluoroethylene-co-ethylene) copolymers has been reported by Tabata [419]. Hill et al. [420] have investigated the effect of environment and temperature on the radiolysis of FEP. While the irradiation is carried out at temperatures above the glass transition temperature of FEP, cross-linking reactions predominate over chain scission or degradation. Forsythe et al. [421]... 

It is on the basis of Lovrien s ideas concerning the photoregulation of polymer conformation in solution by means of photochromic species that Van der Veen Prins reported a first photomechanochemical model transducer, consisting of water-swollen membranes of poly(2-hydroxyethyl methacrylate) cross-linked with ethylene glycol dimethacrylate (1.1 wt-%) in the presence of a sulfonated bis-azostilbene dye (chry-sophenine G), the ratio chrysophenine/2-hydroxyethyl methacrylate being 1/400. 

What accommodations, then, must be made in the pattern of analysis developed for standard synthetic polypeptides if it is to yield quantitative estimates of partial helical content in proteins The requirements are much the same as those set out for poly-L-lysine (see Section III, G, 3), yet since globular proteins, like copolymers of L-lysine and L-glutamic acid, cannot be made completely helical in aqueous solution, a helical reference conformation must be taken either from other standard molecules or from the nonaqueous behavior of the protein in question. This latter procedure involves solvent changes with little bearing on native conditions and may be impossible to carry out in the face of restraints imposed by proline and cross-links, so that standard helical dispersion can more feasibly serve as this reference conformation. 

Eisenbach (1980) investigated the photomechanical effect of poly(ethyl acrylate) networks (3) cross-linked with azobenzene moieties and observed that the polymer network contracted upon exposure to UV light (caused by the trans-cis isomerization of the azobenzene cross-links) and expanded upon irradiation of visible light (caused by cis-trans back-isomerization Fig. 3.5). This photomechanical effect is mainly due to the conformational change of the azobenzene crosslinks by the trans-cis isomerization of the azobenzene chromophore. However, the degree of deformation was small (0.2%). 

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