Polystyrene photochemistry

Nakayama Y., Miyamura M., Hirano Y., Goto K., Matsuda T., Preparation of poly(ethylene glycol)-polystyrene block copolymers using photochemistry of dithiocarbamate as a reduced cell-adhesive coating material, Biomaterials 1999 20 963-970. 

The ketone group is a useful model for other types of chromophores because it can be selectively excited in the presence of other groups in polymer chains such as the phenyl rings in polystyrene and so the locus of excitation is well defined. Furthermore there is a great deal known about the photochemistry of aromatic and aliphatic ketones and one can draw on this information in interpreting the results. A further advantage of the ketone chromophore is that it exhibits at least three photochemical processes from the same excited state and thus one has a probe of the effects of the polymer matrix on these different processes by determination of the quantum yields for the following photophysical or photochemical steps l) fluorescence,... 

The photochemistry of polystyrene has been the subject of a considerable amount of research during the past twenty-five years. Two main approaches have been employed (a) analyses of gaseous products liberated or absorbed during photolyses, and (b) analyses of the polymer residue after the absorption of a given amount of radiation. 

Reusability is a characteristic of the sensitizers prepared by stirring Ceo-fullerene with aminomethylated poly(styrene/vinylbenzene). They have been used to promote the standard O2 oxidation processes such as ene and Diels-Alder reactions (Scheme 7), and catalysts suitable for photoxidations in water have been prepared from them by reaction with poly(allylamine). The same reactions have been carried out using a novel solvent-free procedure which involves loading a porphyrin into solvent-swollen polystyrene beads and carrying out the photo-oxidation in neat liquid substrate. The formation of the allylic hydroperoxide (89) from p-pinene, with complete conversion and in 84% yield, is particularly noteworthy, as the standard liquid-phase reaction can be problematic. It is suggested that the possibility of using this approach under solar conditions is further evidence of the sustainable, green chemistry potential of synthetic photochemistry. 

M.E. Fabiyi, R.L. Skelton, Photocatalytic mineralisation of methylene blue using buoyant Ti02-coated polystyrene beads . Journal of Photochemistry and Photobiology A Chemistry, 132, 121-128, (2000). 

Carbonyl complexes in thin films of polystyrene and other polymers have been studied by Butler et. Polymer films arise again in a paper by Bronshtein et al dealing with the general issue of the photolysis of metal carbonyls in thin films. This technique has become a common and reliable method for exploring metal carbonyl photochemistry. 

Surface block-graft-copolymerization, based on the photochemistry of N, AT-diethyldithiocarbamate has been applied to precisely design biocompatible and functional surfaces (patterns of immobilized heparin or proteins), as well as block-grafted surfaces on polystyrene [83]. Polystyrene surfaces have also been patterned by immobilization of poly(Af-isopropylacrylamide) by photolithography, and subsequently used for regiospecific cell attachment [84]. Surface modification of polydimethylsiloxane microfluidic devices by UV induced polymer grafting improved the stability of the electroosmotic mobility and improved electrophoretic resolution of peptides [85]. 

Nakashima, K., Gong, Y, Watanabe, T., Suzuki, N., and Tokunou, K. 2001. Photochemistry of organic dyes on the surface of polystyrene latex particles in aqueous dispersions. 2001. Abstract of papers, 222nd ACS National meeting, Chicago, IL. 

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