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Potrzebowska N, Cavani O, Kazmierski S, Wegrowe JE, Potrzebowski MJ, Clochard MC. Molecular dynamics between amorphous and crystalline phases of e-beam irradiated piezoelectric PVDF thin films employing solid-state NMR spectroscopy. Polym Degrad Stab 2022. [DOI: 10.1016/j.polymdegradstab.2021.109786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Kobera L, Rohlicek J, Czernek J, Abbrent S, Streckova M, Sopcak T, Brus J. Unexpected Crystallization Patterns of Zinc Boron Imidazolate Framework ZBIF-1: NMR Crystallography of Integrated Metal-Organic Frameworks. Chemphyschem 2017; 18:3576-3582. [DOI: 10.1002/cphc.201701063] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Indexed: 01/07/2023]
Affiliation(s)
- Libor Kobera
- Institute of Macromolecular Chemistry of the Czech Academy of Sciences; Heyrovskeho nam. 2 162 06 Prague 6 Czech Republic
| | - Jan Rohlicek
- Department of Structural Analysis; Institute of Physics of the Czech Academy of Sciences; Na Slovance 2 Praha 8 182 21 Czech Republic
| | - Jiri Czernek
- Institute of Macromolecular Chemistry of the Czech Academy of Sciences; Heyrovskeho nam. 2 162 06 Prague 6 Czech Republic
| | - Sabina Abbrent
- Institute of Macromolecular Chemistry of the Czech Academy of Sciences; Heyrovskeho nam. 2 162 06 Prague 6 Czech Republic
| | - Magdalena Streckova
- Institute of Materials Research of the Slovak Academy of Sciences; Watsonova 47 040 01 Košice Slovak Republic
| | - Tibor Sopcak
- Institute of Materials Research of the Slovak Academy of Sciences; Watsonova 47 040 01 Košice Slovak Republic
| | - Jiri Brus
- Institute of Macromolecular Chemistry of the Czech Academy of Sciences; Heyrovskeho nam. 2 162 06 Prague 6 Czech Republic
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Sorte EG, Alam TM. 1 H- 19 F REDOR-filtered NMR spin diffusion measurements of domain size in heterogeneous polymers. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2017; 55:1006-1014. [PMID: 28577309 DOI: 10.1002/mrc.4623] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 05/24/2017] [Accepted: 05/31/2017] [Indexed: 06/07/2023]
Abstract
Solid state NMR spectroscopy is inherently sensitive to chemical structure and composition and thus makes an ideal method to probe the heterogeneity of multicomponent polymers. Specifically, NMR spin diffusion experiments can be used to extract reliable information about spatial domain sizes on multiple length scales, provided that magnetization selection of one domain can be achieved. In this paper, we demonstrate the preferential filtering of protons in fluorinated domains during NMR spin diffusion experiments using 1 H-19 F heteronuclear dipolar dephasing based on rotational echo double resonance (REDOR) MAS NMR techniques. Three pulse sequence variations are demonstrated based on the different nuclei detected: direct 1 H detection, plus both 1 H➔13 C cross polarization and 1 H➔19 F cross polarization detection schemes. This 1 H-19 F REDOR-filtered spin diffusion method was used to measure fluorinated domain sizes for a complex polymer blend. The efficacy of the REDOR-based spin filter does not rely on spin relaxation behavior or chemical shift differences and thus is applicable for performing NMR spin diffusion experiments in samples where traditional magnetization filters may prove unsuccessful. This REDOR-filtered NMR spin diffusion method can also be extended to other samples where a heteronuclear spin pair exists that is unique to the domain of interest.
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Affiliation(s)
- Eric G Sorte
- Department of Organic Material Science, Sandia National Laboratories, Albuquerque, NM, 87185, USA
| | - Todd M Alam
- Department of Organic Material Science, Sandia National Laboratories, Albuquerque, NM, 87185, USA
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Woźniak-Braszak A. Methodology for solid state NMR study of cross relaxation and molecular dynamics in heteronuclear systems. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2013; 53:38-43. [PMID: 23664759 DOI: 10.1016/j.ssnmr.2013.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Revised: 03/27/2013] [Accepted: 03/28/2013] [Indexed: 06/02/2023]
Abstract
This work presents the theoretical analysis of cross-relaxation and its applications to the study of molecular dynamics in the solid state heteronuclear systems in the laboratory frame. The solid state NMR experiments were carried out on a homemade pulse spectrometer operating at the frequency of 30.2 MHz and 28.411 MHz for protons and fluorines, respectively. It is worth noting that this spectrometer includes a specially designed probe which simultaneously works at two slightly differing frequencies for protons and fluorine nuclei with complete absence of their interference. Contrary to a large number of previous cross-relaxation studies, in our experiments proton spins can be polarized in the magnetic field B0 or excited by rf pulses, while fluorine spins are continuously saturated for a long time. The saturation of fluorines is maintained throughout the whole duration of the experiment. It leads to a simplification of the mathematical analysis of the experimental results.
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Affiliation(s)
- Aneta Woźniak-Braszak
- High Pressure Physics Division, Department of Physics, Adam Mickiewicz University, Poznan, Poland.
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Montina T, Hazendonk P, Wormald P, Iuga D. The refocused discrimination induced by variable amplitude minipulses (DIVAM) experiment — Improved domain selection in semicrystalline fluoropolymers by 19F solid state nuclear magnetic resonance spectroscopy. CAN J CHEM 2011. [DOI: 10.1139/v11-043] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The discrimination induced by variable amplitude minipulses (DIVAM) filter can be tuned to select for signals from a particular domain, therefore it is possible to obtain signals specific to different domains using only one experiment. An early description of the DIVAM sequence, where the filter terminates with cross-polarization, explains this tune ability using a simple one-spin-relaxation model, thereby limiting the selection mechanism to incoherent processes. Recently, a more complete description of the selection behaviour was offered for the DIVAM filter, when it was directly applied to the observed nucleus (direct DIVAM), taking into account both the incoherent and coherent terms. Direct DIVAM experiments on poly(vinylidenefluoride) (PVDF) show significant phase distortions when large excitation angles were used. The signal from the amorphous domain is seen to nutate in a normal fashion with respect to the excitation angle, while those from the crystalline and defect units did not. The refocused DIVAM sequence is introduced to restore normal nutation for all signals. The selection behaviour is investigated using SIMPSON (simulation program for solid-state nuclear magnetic resonance (NMR) spectroscopy) simulations. These illustrate that the isotropic shift terms have been effectively removed and the dipolar term attenuated, such that the chemical shift anisotropy (CSA) leads to domain selection; however, in a different manner than seen in direct DIVAM. Therefore, this sequence provides a method to select on the basis of the CSA term in the presence of both strong dipolar couplings and a large range of isotropic shifts.
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Affiliation(s)
- Tony Montina
- Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada
| | - Paul Hazendonk
- Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada
| | - Philip Wormald
- School of Chemistry, University of St Andrews, Purdie Building, St Andrews, Scotland KY16 9ST, UK
| | - Dinu Iuga
- Department of Physics, University of Warwick, Coventry CV4 7AL, UK
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Hazendonk P, Wormald P, Montina T. The Direct DIVAM Experiment: A Spin Dynamics Analysis. J Phys Chem A 2008; 112:6262-74. [DOI: 10.1021/jp711489d] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Paul Hazendonk
- Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta T1K 3M4, Canada, and School of Chemistry, University of St. Andrews, Purdie Building, St Andrews KY16 9ST, U.K
| | - Philip Wormald
- Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta T1K 3M4, Canada, and School of Chemistry, University of St. Andrews, Purdie Building, St Andrews KY16 9ST, U.K
| | - Tony Montina
- Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta T1K 3M4, Canada, and School of Chemistry, University of St. Andrews, Purdie Building, St Andrews KY16 9ST, U.K
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Tatsuno H, Koseki Y, Ando S. Structure and dynamics of a vinylidene fluoride oligomer and its cyclodextrin inclusion compounds as studied by solid-state 19F MAS and 1H→19F CP/MAS NMR spectroscopy. POLYMER 2008. [DOI: 10.1016/j.polymer.2008.04.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Tatsuno H, Aimi K, Ando S. Solid-state 19F MAS NMR study on the conformation and molecular mobility of poly(chlorotrifluoroethylene). MAGNETIC RESONANCE IN CHEMISTRY : MRC 2007; 45:401-9. [PMID: 17372960 DOI: 10.1002/mrc.1982] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
The temperature dependence of molecular mobility and conformational changes of poly(chlorotrifluoro- ethylene) (PCTFE) have been investigated by solid-state (19)F magic angle spinning (MAS) NMR spectroscopy. The pulse techniques of dipolar-filter and T(1rho)-filter allow selective observation of the amorphous and crystalline domains, respectively. The temperature dependence of T(1rho) (F) revealed that the segmental motion in the amorphous domain becomes vigorous above ca 80 degrees C, which is well above the glass transition (T(g)) temperature (52 degrees C) and more close to the beta-relaxation temperature (95 degrees C). On the other hand, vigorous molecular motions in the crystalline domain occur above 120 degrees C, which is much below the melting temperature (212 degrees C). This indicates that the polymer chains in the PCTFE crystallites are more mobile than those of typical semicrystalline fluoropolymers like poly(vinylidene fluoride) (PVDF), which can be associated with structural imperfections in the crystallites. In addition, the density functional theory (DFT) calculations of (19)F magnetic shielding suggest that the high-frequency shifts observed for the crystalline signals above 80 degrees C can be ascribed to the conformational change around meso diads toward more twisted and/or helical conformations in the main chain.
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Affiliation(s)
- Hiroto Tatsuno
- Department of Organic and Polymeric Materials, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo 152-8552, Japan
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Ando S, Harris RK, Hazendonk P, Wormald P. Selective NMR Pulse Sequences for the Study of Solid Hydrogen-Containing Fluoropolymers. Macromol Rapid Commun 2005. [DOI: 10.1002/marc.200400517] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Brus J, Petrícková H, Dybal J. Influence of local molecular motions on the determination of 1H-1H internuclear distances measured by 2D 1H spin-exchange experiments. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2003; 23:183-197. [PMID: 12787902 DOI: 10.1016/s0926-2040(03)00018-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Analysis of spin-exchange build-up curves obtained by measurement of 2D 1H CRAMPS spectra of alpha-glycine was performed to evaluate the rate of 1H-1H spin-exchange process with respect to the influence of variation in internal molecular motion. Differences in local motions significantly affect spin-exchange constants even in highly rigid organic solids with virtually uniform motion behavior. The polarization transfer between nonequivalent alpha-protons is described by the spin-exchange constant D=0.77 nm(2)ms(-1), while the polarization transfer involving spin exchange between alphaH and NH(3)(+) protons is characterized by D=0.24-0.21 nm(2)ms(-1). This significant decrease corresponds to rotation of hydrogen-bonded amino groups. Neglecting this variation in local spin-exchange constants the resulting calculated 1H-1H distance can be overestimated by up to 100%. Complications following from relayed and back polarization transfer involving the nearest spins within one functional group (e.g., CH(2) and/or NH(3)(+)) and intermolecular spin exchange are discussed. It was shown that 2H quadrupolar splitting determined for selected sites directly correlates with the experimentally observed differences in spin-exchange coefficients. It is also demonstrated that a medium level quantum chemical calculation of molecular dynamics provides relevant data that can be used to estimate differences in molecular motions.
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Affiliation(s)
- J Brus
- Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovsky Sq. 2, 162 06 Prague 6, Czech Republic.
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Hazendonk P, Harris RK, Ando S, Avalle P. The DIVAM sequence: selective excitation of signals from both rigid and mobile domains in a fluoropolymer. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2003; 162:206-216. [PMID: 12762997 DOI: 10.1016/s1090-7807(03)00048-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Simulations have been carried out on z-magnetizations produced by (and hence of the resulting spectra from) the dipolar filter (DF) and the recently suggested "Discrimination Induced by Variable-Amplitude Minipulses" (DIVAM) pulse sequences [S. Ando et al., Polymer 42 (2001) 8137; Magn. Reson. Chem. 40 (2002) 97]. The strengths of dipolar interactions have been modelled by introducing different values for transverse relaxation times. The DF case has been extended by allowing the pulse angles to be smaller than 90 degrees. The pulse intervals have also been used as variables. For the DIVAM case, the variables are similarly the minipulse nutation angles and minipulse intervals. The computations show that DIVAM is superior to DF in terms of selectivity for spectra of heterogeneous materials such as semi-crystalline polymers. The effects of the pulse sequences on 19F spectra of poly(vinylidene fluoride) (PVDF) and of a copolymer of vinylidene fluoride and trifluoroethylene (p(VDF/TrFE)) are presented, together with fits of the experimental results by the simulations.
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Affiliation(s)
- Paul Hazendonk
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive W., Alta., T1K 3M4, Lethbridge, Canada.
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Fluorine-19 solid-state NMR investigation of regiodefective semicrystalline α-poly(vinylidenefluoride). POLYMER 2003. [DOI: 10.1016/s0032-3861(02)00821-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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