Determination of Molecular Orientational Order in Cold-Stretched Poly(p-phenylene vinylene) Thin Films by DECODER 13C NMR

Kropewnicki, Michelle L.; Schaefer, D.; Hehn, Manfred; Dermaut, Wim; Geise, H. J.; Chmelka, Bradley F.

doi:10.1006/snmr.2002.0082

Cited by 7 publications

(10 citation statements)

References 38 publications

(102 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This cold method is experimentally easier than the hot-stretching method and leads to less film tearing and the experimental parameters are much less critical, while a comparable degree of molecular orientation is obtained according to FTIR dichroic measurements. Previously reported data 5 confirm that the molecular orientation is a lot higher than predicted by the existing Kratky model. ,,− Recently, the degree of orientation determined with solid-state NMR measurements was reported, and in the present paper wide-angle X-ray diffraction (WAXD) data are added. The combination of the results obtained by these three techniques makes a more elaborate discussion of the molecular orientation possible, and an attempt to explain the deviation from the Kratky model is presented.…”

Section: Introductionsupporting

confidence: 65%

A Volume-Corrected Kratky Model and the Influence of the Shape of the Orientation Distribution Function on the Molecular Orientation in PPV and Its Precursor

et al. 2003

View full text Add to dashboard Cite

The molecular orientation in cold-stretched PPV films was studied with synchrotron WAXD. The results showed that the degree of orientation is comparable to that of hot-stretched films and that it exceeds the latter's orientation for the lower stretch ratios. The values from WAXD and those from previous FTIR dichroic and DECODER NMR measurements are in agreement with each other, but the observed orientation is far higher than predicted by the Kratky model. Therefore, a volume-corrected Kratky model was derived, which takes into account the extra orientation induced by the volume reduction of the polymer during the thermal elimination process. To fully explain the observed orientation values, however, the shape of the orientation distribution function had to be considered as well. It is concluded that this shape should be close to a Gaussian rather than to a Kratky distribution. The orientation in stretch-aligned noneliminated precursor films is discussed as well.

show abstract

Section: Introductionsupporting

confidence: 65%

A Volume-Corrected Kratky Model and the Influence of the Shape of the Orientation Distribution Function on the Molecular Orientation in PPV and Its Precursor

et al. 2003

View full text Add to dashboard Cite

show abstract

“…Despite the great development of advanced NMR for studying molecular dynamics, there exist so far only few applications of such modern solid-state NMR techniques for investigating dynamics and structure of conjugate polymers. 10,11 In this work, a systematic study of the MEH-PPV chain dynamics using conventional and new advanced solid-state NMR methods is presented. Slow ͑1 Hz-1 kHz͒, intermediate ͑10 kHz-100 kHz͒, and fast dynamics ͑ϳ100 MHz͒ were probed by different NMR techniques.…”

mentioning

confidence: 99%

Solid-state nuclear magnetic resonance study of relaxation processes in MEH-PPV

et al. 2005

View full text Add to dashboard Cite

Solid-state nuclear magnetic resonance methods were used to study molecular dynamics of MEH-PPV at different frequency ranges varying from 1 Hz to 100 MHz. The results showed that in the 213 to 323 K temperature range, the motion in the polymer backbone is predominantly slow ͑Hz-kHz͒ involving small angle librations, which occurs with a distribution of correlation times. In the side chain, two motional regimes were identified: Intermediate regime motion ͑1-50 kHz͒ for all chemical groups and, additionally, fast rotation ͑ϳ100 MHz͒ for the terminal CH 3 group. A correlation between the motional parameters and the photoluminescent behaviors as a function of temperature was observed and is discussed.

show abstract

“…The presence of regions with different molecular order in PPV have been confirmed recently by 2D-NMR DECODER experiments. 8 Another new feature of the exchange NMR results presented here is the separation between flip imprecision ͑or, alternatively, flip coupled with small angle oscillations͒ and pure small-angle oscillations, which was only possible by combining the 2D MAS exchange, CODEX, and NR-CODEX techniques.…”

Section: Motional Amplitudes Probed By Codexmentioning

confidence: 91%

Conformational dynamics of phenylene rings in poly(p-phenylene vinylene) as revealed by 13C magic-angle-spinning exchange nuclear magnetic resonance experiments

deAzevedo

Franco

Marletta

et al. 2003

The Journal of Chemical Physics

View full text Add to dashboard Cite

Exploring the conformational energy landscape of glassy disaccharides by cross polarization magic angle spinning C 13 nuclear magnetic resonance and numerical simulations. II. Enhanced molecular flexibility in amorphous trehalose J. Chem. Phys. 126, 014511 (2007); 10.1063/1.2409935 Double-quantum homonuclear correlation magic angle sample spinning nuclear magnetic resonance spectroscopy of dipolar-coupled quadrupolar nuclei

show abstract

Determination of Molecular Orientational Order in Cold-Stretched Poly(p-phenylene vinylene) Thin Films by DECODER 13C NMR

Cited by 7 publications

References 38 publications

A Volume-Corrected Kratky Model and the Influence of the Shape of the Orientation Distribution Function on the Molecular Orientation in PPV and Its Precursor

A Volume-Corrected Kratky Model and the Influence of the Shape of the Orientation Distribution Function on the Molecular Orientation in PPV and Its Precursor

Solid-state nuclear magnetic resonance study of relaxation processes in MEH-PPV

Conformational dynamics of phenylene rings in poly(p-phenylene vinylene) as revealed by 13C magic-angle-spinning exchange nuclear magnetic resonance experiments

Contact Info

Product

Resources

About