Maria Nowakowska

Studies of the antenna effect in polymer molecules: Photosensitized oxidation of perylene in an aqueous solution of poly(sodium styrenesulfonate-co-2-vinylnaphthalene)

Abstract The photosensitized oxidation of perylene solubilized in an aqueous solution of poly(sodium styrenesulfonate-co-2-vinylnaphthalene) (PSSS-VN) was studied. The process was shown to occur in the hydrophobic polymeric microdomains where perylene is solubilized. Two major secondary oxidation products, 3,10-perylenequinone and 1,12-perylenequinone, were identified. On the basis of the product analysis, a mechanism for the photosensitized oxidation of perylene in aqueous PSSS-VN solution is proposed involving the participation of singlet oxygen.

Studies of the antenna effect in polymer molecules 25. Photozymes with rose bengal chromophores

Abstract Several copolymers of poly(sodium styrenesulfonate-styrene-vinylbenzylchloride) and poly(sodium styrenesulfonate-2-vinylnaphthalene- vinylbenzylchloride) containing various amounts of rose bengal chromophores attached to the polymer chain were synthesized. The copolymers are soluble in water and can solubilize large hydrophobic compounds. They are efficient genarators of singlet oxygen, and act as photosensitizers in the oxidation of singlet oxygen acceptors which are dissolved in the water phase and solubilized in the hydrophobic polymeric microdomains.

Studies of the antenna effect in polymer systems 16: synthesis and properties of water-soluble poly(sodium styrenesulfonate-CO-9-(p-vinylphenyl)anthracene)

Abstract Poly(sodium styrenesulfonate- co -9-vinylphenyl)anthracene copolymers (PSSS-VPA) of different compositions were synthesized. The copolymers containing up to 33 mol % of 9-vinylphenylanthracene are water soluble. In aqueous solutions the macromolecules appear to adopt a compact conformation which makes possible the solubilization of large hydrophobic compounds such as perylene (P), tetraphenyl porphine and 1,3-diphenylisobenzofuran (DPBF). The PSSS-VPA copolymers were found to be very efficient photosensitizers in the oxidation of P and DPBF. It was observed, however, that the photostability of the polymers in the presence of oxygen is limited.

Studies of the antenna effect in polymer molecules 19. Synthesis, solubilizing and photocatalytic activity of several methacrylic acid—9-vinylphenanthrene copolymers

Abstract A block copolymer of methacrylic acid (MA) and 9-vinylphenanthrene (9-VPh) was prepared by anionic polymerization, and several poly(methacrylic acid-co-9-vinylphenanthrene) (PMA—9-VPh) polymers were synthesized by free-radical polymerization. All copolymers are water soluble and display solubilizing ability towards hydrophobic probes in aqueous solution. The relative hydrophobicity of the solubilizing microdomains in aqueous solutions of PMA—9-VPh copolymers, determined using pyrene as an environment-sensitive probe, is high. The effect of the pH and ionic strength of the solution on the solubilization ability of the copolymers was studied. The PMA—9-VPh copolymers act as efficient photocatalysts in the photo-oxidation of perylene. The block copolymer is the most efficient photocatalyst. The differences between the photocatalytic efficiencies of random and block copolymers demonstrate the importance of the antenna effect in synthetic polymers.

Studies of the antenna effect in polymer molecules 22. Photochemical dechlorination of polychlorinated biphenyls in aqueous solutions of poly(sodium styrenesulfonate-co-2-vinylnaphthalene)

Abstract The photodechlorination of three commercial mixtures of polychlorinated biphenyls (PCBs), solubilized in aqueous solutions of poly(sodium styrenesulfonate-co-2-vinylnaphthalene) (PSSS-VN), was studied using solar-simulated radiation. Gas chromatographic analysis showed that, following irradiation, Aroclor 1254, Aroclor 1248 and Aroclor 1242 were progessively dechlorinated to tri-, di- and monochlorobiphenyls. Photodechlorination of Aroclor 1254 was found to be more efficient when solubilized in aqueous solutions of PSSS-VN than solubilized in hexane. The reaction was determined to be photosensitized by the naphthalene antenna units present in the copolymer.

Studies of the antenna effect in polymer molecules 29. Isomerization of provitamin D3 photosensitized by polymers containing pendant naphthalene groups

Abstract The photosensitized isomerization of provitamin D3 was studied in THF solutions of styrene-2-vinylnapthalene copolymers, poly(2-vinylnaphthalene poly(2-isopropenylnaphthalene) and poly(acenaphthalene). The effect of efficiency of excimer formation and energy migration on the quantum efficiency of previtamin formation was demonstrated.

Studies of the antenna effect in polymer molecules. 27. Hydrogen evolution from water

Abstract The light-induced formation of hydrogen from water was studied using polyelectrolytes containing naphthalene antenna chromophores as sensitizer. Viologen compounds were employed as electron relay. In the presence of platinum catalyst, the systems produced hydrogen efficiently on irradiation with light at λ = 300 nm. Natural solar light can also be used to generate hydrogen in such systems.