A solid-state n.m.r. study of microphase structure and segmental dynamics of poly(styrene-b-methylphenylsiloxane) diblock copolymers

Cai, Wenwen; Schmidt‐Rohr, Klaus; Egger, Norbert; Gerharz, B.; Spiess, Hans Wolfgang

doi:10.1016/0032-3861(93)90077-n

Cited by 92 publications

(104 citation statements)

References 21 publications

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“…The deviations are within 5%. Moreover, the deviation is quite insensitive to the mixing times, in contrast to earlier observations 17,20 where deviations increase at longer mixing times. The simulated long cubic period was found to be 24.6 nm, also close to the small angle X-ray scattering value of 27.6 nm based on a two-phase model in a body-centered-cubic lattice.…”

Section: B the Interfacial Thicknesscontrasting

confidence: 94%

“…As pointed out before, 20 the presence of an interphase causes a slow increase of the NMR signal at short mixing times and an earlier equilibration for the spin diffusion process. This results in a sigmoidal behavior for the spin diffusion curve.…”

Section: B the Interfacial Thicknessmentioning

confidence: 54%

“…15,20 Tanaka and Nishi 22 found that the interphase to be 2.6 nm for a PS-b-PI copolymer of a different molecular weight by studying the spin-spin relaxation behavior. The earlier small angle X-ray scattering 23 and small angle neutron scattering 24 estimated a 2 nm interphase in similar systems.…”

Section: B the Interfacial Thicknessmentioning

confidence: 99%

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Spin diffusion and spin-lattice relaxation in multiphase polymers

Wang

Jack

Natansohn

1997

The Journal of Chemical Physics

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Reuse of AIP Publishing content is subject to the terms: https://publishing.aip.org/authors/rights-and-permissions. A model which treats spin diffusion and spin-lattice relaxation in multiphase polymers on the same footing is proposed. This new approach allows for more accurate determination of domain sizes and interfacial thickness in the probed polymers. In a poly͑styrene-b-isoprene͒ copolymer example a significant improvement in the agreement between the NMR measurements and the simulated results can be obtained with the incorporation of a spin-lattice relaxation term into the spin diffusion process. The obtained microphase structural parameters are similar to the small angle X-ray scattering results. In addition, the spin-lattice relaxation times ͑T 1 ) in different domains can be predicted reasonably well based on T 1 s of the component homopolymers and on the microphase structure in the present model.

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Section: B the Interfacial Thicknesscontrasting

confidence: 94%

Section: B the Interfacial Thicknessmentioning

confidence: 54%

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Spin diffusion and spin-lattice relaxation in multiphase polymers

Wang

Jack

Natansohn

1997

The Journal of Chemical Physics

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“…One could either retain the quantitative aspect by observing protons and using very fast MAS (g30 kHz) and high fields (g600 MHz), requiring the resolution of ambiguities in phase-specific detection (by deconvolution of lines with different width) and severely reduced spin diffusion coefficients. 23 An alternative is of course the well established, but more time-consuming and less quantitative indirect observation via a short, thus rigid-phase specific cross-polarization to 13 C. 10,11,13 A possible limitation that has as yet not been addressed in the spin diffusion literature is the distinction between a faster intrachain transfer (along a curvilinear path) and a slower, interchain transfer, in particular for the mobile phase. This would correspond to locally anisotropic spin diffusion effects as a result of different intra-and interchain residual dipolar couplings.…”

Section: Resultsmentioning

confidence: 99%

“…[10][11][12][13] In such experiments, the initial proton magnetization is selectively suppressed in one of the phases (most often the rigid phase, using "dipolar filters" that suppress signal from strongly dipolarcoupled segments), and then re-equilibrates due to an also dipolar-mediated flip-flop process that has the characteristic of a diffusion process and provides spatial information.…”

Section: Introductionmentioning

confidence: 99%

Direct Observation of Interphase Composition in Block Copolymers

et al. 2008

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We demonstrate the fast, direct, and quantitative observation of temperature-and comonomerinduced changes in the interfacial size and composition in phase-separated styrene-butadiene-styrene block copolymers by double-quantum-filtered proton spin-diffusion NMR experiments performed under high-resolution magic-angle spinning conditions. The experiment is based on the dipolar-mediated diffusion of spin magnetization from the (styrenic) rigid phase through a more mobile interphase of variable size and composition into the soft (polybutadiene) domain. The experiment spectroscopically distinguishes between mobilized styrene segments located in the interphase and those mixed (dissolved) in the bulk of the mobile domain. The results indicate that temperature-induced softening due to mobilization of styrene units at the interface and the tendency to become part of an extended interphase is stronger for systems with a lower segregation strength, having statistically distributed styrene comonomers in the soft domain.

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Nuclear Magnetic Resonance, Solid State in Analysis of Polymers and Rubbers

Mirau¹

2000

Encyclopedia of Analytical Chemistry

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Solid‐state nuclear magnetic resonance (NMR) has emerged as one of the premier methods for polymer characterization in the solid‐state. High‐resolution spectra can be obtained with cross‐polarization and magic‐angle sample spinning using equipment that is commonly available on modern NMR spectrometers. Information about the chain structure, conformation, dynamics, intermolecular interactions and the morphology can be obtained by measuring the chemical shifts, line shapes and relaxation times. New experiments have been developed to filter the NMR response such that the spectrum from aparticular component can be measured. The resolution has been increased with the development of multidimensional NMR methods for measuring the structure and dynamics. Solid‐state NMR experiments can provide the link between the chemical structure and the macroscopic properties of polymers.

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A solid-state n.m.r. study of microphase structure and segmental dynamics of poly(styrene-b-methylphenylsiloxane) diblock copolymers

Cited by 92 publications

References 21 publications

Spin diffusion and spin-lattice relaxation in multiphase polymers

Spin diffusion and spin-lattice relaxation in multiphase polymers

Direct Observation of Interphase Composition in Block Copolymers

Nuclear Magnetic Resonance, Solid State in Analysis of Polymers and Rubbers

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