TITLE

Segment diffusion and nuclear magnetic resonance spin-lattice relaxation of polymer chains confined in tubes: Analytical treatment and Monte Carlo simulation of the crossover from Rouse to reptation dynamics

AUTHOR(S)
Denissov, Alexei; Kroutieva, Margarita; Fatkullin, Nail; Kimmich, Rainer
PUB. DATE
March 2002
SOURCE
Journal of Chemical Physics;3/22/2002, Vol. 116 Issue 12, p5217
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
The frequency and molecular mass dependences of nuclear magnetic resonance spin-lattice relaxation and the time dependence of the mean-squared segment displacement of Kuhn segment chains confined in static straight and randomly coiled tubes with "soft" and "hard" walls were studied. "Soft" walls were modeled in the form of a cylindrical distribution of a harmonic radial potential. This scenario is analytically solvable in contrast to the situation of "hard" (reflecting) walls corresponding to an infinitely deep square-well radial potential. In the latter case, we have therefore employed Monte Carlo simulations using a modified Stockmayer chain model. In both situations, qualitatively equivalent results were obtained. Depending on the effective tube diameter (or width of the potential well) a crossover from Rouse to reptation behavior occurs which sets on already far beyond the Flory radius of the polymer. In terms of the spin-lattice relaxation dispersion, reptation reveals itself by T[sub 1] ∝ M[sup 0]ω[sup 3/4] in the chain mode regime, in good agreement with experimental data for polymers in artificial tubes reported in our previous paper by Kimmich et al.
ACCESSION #
6327605

 

Related Articles

  • Spin diffusion and spin-lattice relaxation in multiphase polymers. Jiahu Wang; Jack, Kevin S. // Journal of Chemical Physics;7/15/1997, Vol. 107 Issue 3, p1016 

    Presents a model which treats spin diffusion and spin-lattice relaxation in multiphase polymers on the same footing. Features of the new approach that allows for more accurate determination of domain sizes and interfacial thickness in the probed polymers; Techniques for obtaining microphase...

  • Chain dynamics in entangled polymers: Power laws of the proton and deuteron spin-lattice.... Kimmich, R.; Fatkullin, N. // Journal of Chemical Physics;2/1/1998, Vol. 108 Issue 5, p2173 

    Examines the chain modes of entangled polymers using the field-cycling proton or deuteron relaxometry. Frequency dispersion of proton and spin-lattice relaxation; Relationship between crossover frequencies and polymer temperature; Implications of dipole-dipole coupling for proton relaxation.

  • Nuclear spin-lattice relaxation dispersion and segment diffusion in entangled polymers. Renormalized Rouse formalism. Fatkullin, N.; Kimmich, R. // Journal of Chemical Physics;7/1/1994, Vol. 101 Issue 1, p822 

    A formalism for polymer melts was derived linking the spin-lattice relaxation time T1, the correlation function of chain tangent vectors and the mean-square segment displacement with memory functions. Potential normal-mode number dependences are included. In the limit of infinitely fast decaying...

  • Proton rotating frame spin-lattice relaxation study of slow motion of pore water. Holly, R.; Peemoeller, H. // Journal of Chemical Physics;3/8/1998, Vol. 108 Issue 10, p4183 

    Examines the proton rotating spin-lattice relaxation study of water in hydrated porous silica glass. Detection of the relaxation times in well-defined dispersion; Motion of the molecules between the binding site and pore-core water; Variation of the pore-core water molecule with correlation time.

  • NMR studies of alkali-doped C[sub 60] polymers. Maniwa, Y.; Ikejiri, H.; Tou, H.; Masubuchi, S.; Kazama, S.; Yasukawa, M.; Yamanaka, S. // AIP Conference Proceedings;2001, Vol. 590 Issue 1, p443 

    [sup 23]Na- and [sup 13]C-NMR of NaC[sub 60] heat-treated under high-pressure are presented, and the results are compared with those of Li[sub χ]C[sub 60] polymers. The [sup 13]C-NMR spectra clearly showed the existence of sp³ carbon atoms, evidencing for the transformation to the C[sub...

  • Confinement effects on dipolar relaxation by translational dynamics of liquids in porous silica glasses. Korb, J.-P.; Xu, Shu; Jonas, J. // Journal of Chemical Physics;2/1/1993, Vol. 98 Issue 3, p2411 

    A theory of dipolar relaxation by translational diffusion of a nonwetting liquid confined in model porous media is presented. We obtain expressions of the rates of spin-lattice relaxation 1/T1, spin–spin relaxation 1/T2, and spin-lattice relaxation in the rotating frame 1/T1ρ, which...

  • The anomalous adsorbate dynamics at surfaces in porous media studied by nuclear magnetic.... Zavada, Tatiana; Kimmich, Rainer // Journal of Chemical Physics;10/22/1998, Vol. 109 Issue 16, p6929 

    Examines adsorbate molecule diffusion along porous media surfaces related to the ordinary and Levy walk diffusion mechanisms. Influence of surface dynamics and geometry in spin-lattice relaxation dispersion; Usage of polar and non-polar liquids; Impact of frozen sample on reorientation...

  • The diffusion–spin relaxation time distribution function as an experimental probe to characterize fluid mixtures in porous media. Hürlimann, M. D.; Venkataramanan, L.; Flaum, C. // Journal of Chemical Physics;12/8/2002, Vol. 117 Issue 22, p10223 

    The distribution function between diffusion and spin relaxation time is shown to be a powerful tool to characterize fluid mixtures in porous media. We discuss the nuclear magnetic resonance measurements using diffusion-editing sequences that were developed to measure this quantity. A recently...

  • Dynamic effects of pair correlation functions on spin relaxation by translational diffusion in two-dimensional fluids. Korb, J.-P.; Ahadi, M.; Zientara, G. P.; Freed, J. H. // Journal of Chemical Physics;2/1/1987, Vol. 86 Issue 3, p1125 

    The dynamic effects of pair correlation functions (pcf) on spin relaxation by translational diffusion in infinite two-dimensional fluids are considered explicitly through a Smoluchowski equation, for the usual conditional probability, with appropriate boundary conditions, especially at the...

Share

Read the Article

Courtesy of VIRGINIA BEACH PUBLIC LIBRARY AND SYSTEM

Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics