Vinylnaphthalene-containing polymers

Quantum Yields for Scission in Vinylnaphthalene-Containing Polymers and Methylnaphthalene Mixtures in DMM... 

Most interest of vinyl arene containing polymers focused on vinylnaphthalenes, vinylpyrenes, vinylanthracenes, vinylphenanthrenes and vinylbiphenyls. The research work until 1968 was summerized by Heller and Anyos [314],... 

A similar but smaller intramolecular quenching effect was seen by Phillips and co-workers 44,4S) for 1-vinylnaphthalene copolymers incapable of excimer fluorescence. The monomer fluorescence lifetime of the 1-naphthyl group in the methyl methacrylate copolymer 44) was 20% less than the lifetime of 1-methylnaphthalene in the same solvent, tetrahydrofuran. However, no difference in lifetimes was observed between the 1-vinylnaphthalene/methyl acrylate copolymer 45) and 1-methylnaphthalene. To summarize, the nonradiative decay rate of excited singlet monomer in polymers, koM + k1M, may not be identical to that of a monochromophoric model compound, especially when the polymer contains quenching moieties and the solvent is fluid enough to allow rapid intramolecular quenching to occur. 

Only one excimer fluorescence peak and lifetime were observed l2) for R—CH2— CH2-CHX-R, where R = 2-naphthyl and X = H 121>, methyl, dodecyl, or p-phenylethyl. The same was also true for meso- and d/-2,4-bis(2-naphthyl)pentane12). A recent report128) attributing the fluorescence peaks at 345, 363, and 381 nm in the spectrum of poly(2- er/butyl-6-vinylnaphthalene) to a second excimer species must therefore be considered invalid. The polymer undoubtedly contains an in-chain impurity with vinylnaphthalene conjugation, as discussed in Section 2.1.9.2 for a similar claim involving P2VN 33). 

Phosphorescence studies in isobutylene-methyl methacrylate-1-naphthyl-methyl methacrylate co-polymer provided evidence to show that in very dilute solution the chain collapses into more compact structures, and intramolecular excimer formation in poly-(2-vinylnaphthalene) has been shown to exhibit non-Stokes-Einstein behaviour. Laser photolysis of polymers containing phenanthryl groups, such as poly-(9-vinylphenanthrene), indicates the presence of plural dimer sites having different geometries owing to the stacking effect of phenanthrene chromophores. In poly-(2-naphthyl methacrylate). 

Consequently, the modification of method (1) for the determination of the rate parameters descriptive of intramolecular excimer formation in ct rolymers containing vinylnaphthalene is justified. It is important to note however that since the pre-exponential terms Ai and A2 are altered by the presence of M, the presence of such a species will invalidate application of the single concentratfon technique (method (2)) to polymers in whfch dual exponentiality in the decay analyds is not observed. 

The second class contains a fluorescent chromophore, also referred to as a fluorophore, on every repeat unit, either pendent to the chain or in the backbone. Examples of compounds having chromophores pendent to the chain are polystyrene and poly(2-vinylnaphthalene), both of which have been extensively studied as components of polymer blends (7-i3). Compounds having chromophores in the backbone are represented by an aromatic polyamide, polyester (14), or polyurethane (15). 

Synthesis of co-polymers allows an alternative to ordinary concentration effects to be studied - namely, the separation of the chromophores on a given polymer chain may be varied. In copolymers of 1-vinylnaphthalene and styrene containing as little as 3 to 4 mole% of the vlnylnaphthalene units, it has been shown that sequences of two or more adjacent units containing naphthyl groups must be present for excimer formation to occur (60). In solid polymers local order exists such that energy migration between adjacent chains can occur, and this has been substantiated... 

Delayed emission spectra in 1 1 diethylethertetra-hydrofuran glasses. Curve A Styrene-1-vinyl-naphthalene copolymer containing 1 mol percent 1-vinylnaphthalene derived groups. Curve B Mixture of polystyrene and poly(l-vinylnaphthalene) polymers 1... 

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