Quantitative measurement of chain contraction in a solid blend of two incompatible polymers: poly(methyl methacrylate)/poly(vinyl acetate)

Peterson, Kent D.; Stein, Alan; Fayer, M. D.

doi:10.1021/ma00203a020

Cited by 54 publications

(58 citation statements)

References 8 publications

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“…In the present experiments, r(t) is observed to have a maximum value of ∼0.25. This value has also been observed in all other studies using naphthalene as a fluorescence anisotropy probe, 4,5,24,26 including those experiments in which the naphthyl was attached to a polymer backbone in a solid polymeric sample at low temperature. Thus, it is unlikely that the observed maximum value of r(t) deviates from the theoretical maximum due to a very fast unresolved motion of the chromophore.…”

Section: A Measurement Of O(t)supporting

confidence: 77%

“…This method has been applied to the study of polymer glasses, [1][2][3][4][5] melts, [6][7][8] and blends. 4,8,9 To investigate polymer structure with EET-induced fluorescence depolarization, it is necessary to incorporate fluorophores into the polymer chains. This is possible by copolymerizing the probe either into the polymer backbone or pendant to it, as a side chain.…”

Section: Introductionmentioning

confidence: 99%

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Polystyrene Size Determination in Polystyrene and Poly(vinyl methyl ether) Using Electronic Excitation Transport

1998

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Poly(styrene-co-2-vinylnaphthalene) with a 1.25% fraction of naphthyl fluorophores is studied in two polymeric hosts, polystyrene and poly(vinyl methyl ether). In the polystyrene host, measurement of the electronic excitation transport-induced fluorescence polarization anisotropy decay, r(t), in conjunction with a previous quantitative statistical theory of electronic excitation transport on lightly tagged polymer chains, allows a determination of the copolymer radius of gyration. Comparison with light scattering measurements from the literature establishes the θ-condition nature of this solid system. Poly(vinyl methyl ether) forms a compatible polymer blend with polystyrene. Analysis of r(t) data shows that the radius of gyration of a copolymer molecule is expanded in poly(vinyl methyl ether) relative to the θ-condition at room temperature. The synthesis of poly(styrene-co-2-vinylnaphthalene) is detailed.

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Section: A Measurement Of O(t)supporting

confidence: 77%

Section: Introductionmentioning

confidence: 99%

Polystyrene Size Determination in Polystyrene and Poly(vinyl methyl ether) Using Electronic Excitation Transport

1998

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“…Details of the apparatus can be found elsewhere. 105 Excitation pulses were provided by a cavity-dumped dye laser running at 640 nm frequency-doubled to 320 nm for DMNA and 600 nm frequency-doubled to 300 nm for DMA. Photons were detected with a Hamamatsu microchannel plate detector in combination with a subtractive double monochromator tuned to 422 nm for DMNA and 370 nm for DMA.…”

Section: Methodsmentioning

confidence: 99%

Photoinduced Intermolecular Electron Transfer in Micelles: Dielectric and Structural Properties of Micelle Headgroup Regions

2001

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Photoinduced intermolecular (donor/acceptor) electron transfer is studied both experimentally and theoretically for donors and acceptors located in the headgroup region of micelles. Fluorescence up-conversion and fluorescence yield measurements were performed to characterize photoinduced electron transfer from N,Ndimethylaniline (DMA) and N,N-dimethyl-1-naphthylamine (DMNA) to octadecylrhodamine B (ODRB) in three types of aqueous micelle solutions: dodecyl-, tetradecyl-, and cetyltrimethylammonium bromide (DTAB, TTAB, and CTAB, respectively). The data were analyzed with a detailed theory that assumes a Marcus distance-dependent rate constant. Because DMA, DMNA, and ODRB reside in the headgroup region of the micelles, the theory includes diffusion of the molecules in this region of the micelles. The micelles are modeled as a spherical core of low dielectric constant surrounded by a spherical shell headgroup region with intermediate dielectric properties, which in turn is surrounded by water. An analytical theory, which accounts for geometrical and dielectric properties of the three-region micelle environment, is used to calculate the solvent reorganization energy and free energy of transfer. To fit the data, the three-region dielectric model is necessary, and the dielectric constant of the micelle headgroup region of each micelle can be approximately determined. In addition, including local structure is required to fit the data, yielding some information about molecular organization in the headgroup region.

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“…An analytical theory of 〈G s (t)〉 was developed for EET among chromophores on an ensemble of isolated chains (no interchain transfer). 14 This theory has been shown to be accurate through experiments 15 and comparison to detailed simulations. 5,8 An analytical theory was also developed for interchain EET, i.e., the contribution to 〈G s (t)〉 from excitations that transfer from chromophores on copolymer chains containing the initially excited chromophores to chromophores on other copolymer chains.…”

Section: Experimental Methodsmentioning

confidence: 92%

Phase Separation in Binary and Ternary Polymer Composites Studied with Electronic Excitation Transport

Hussey

Fayer

1999

Macromolecules

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Time-resolved fluorescence polarization anisotropy decay measurements are used to observe the process of phase separation of molecularly mixed polymer blends. The binary blends are composed of a low concentration of poly[methyl methacrylate-co-2-vinylnaphthalene] (PMMA2VN) in poly[vinyl acetate] (PVAc). The small number of 2VN groups on the PMMA2VN chains act as fluorescent chromophores. Electronic excitation transport (EET) among these chromophores contributes to the decay of their fluorescence polarization anisotropy, which is measured with time-correlated single photon counting. Since EET is highly sensitive to the distances between chromophores, it reflects their spatial distribution and can reveal both the isolated-chain structure and the aggregation of polymer chains in the blend on the nanometer distance scale. Blend samples are prepared by annealing a homogeneous blend at an elevated temperature for a given time and then rapidly quenching the phase-separating material below its glass-transition temperature. The newly formed nanoscopic aggregates frozen in the sample are then investigated with EET. The ternary blends are composed of a very small amount of PMMA2VN and a larger quantity of PMMA, both in bulk PVAc. In the phase separation of ternary blends, the PMMA2VN component initially partitions with its chromophore-free counterpart, expanding to its θ-condition size before continuing to aggregate and eventually separating from the PMMA.

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Quantitative measurement of chain contraction in a solid blend of two incompatible polymers: poly(methyl methacrylate)/poly(vinyl acetate)

Cited by 54 publications

References 8 publications

Polystyrene Size Determination in Polystyrene and Poly(vinyl methyl ether) Using Electronic Excitation Transport

Polystyrene Size Determination in Polystyrene and Poly(vinyl methyl ether) Using Electronic Excitation Transport

Photoinduced Intermolecular Electron Transfer in Micelles: Dielectric and Structural Properties of Micelle Headgroup Regions

Phase Separation in Binary and Ternary Polymer Composites Studied with Electronic Excitation Transport

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