title: Investigations of polymer dynamics in nanoporous media by field cycling NMR relaxometry and the dipolar correlation effect.
abstract: The chain dynamics of short-chain perfluoropolyether melts confined in Vycor nanoporous media has been characterized by field cycling nuclear magnetic resonance relaxometry and the dipolar correlation effect. The slowdown of motions under confinement, leading to larger residual dipolar couplings, has been probed by looking at the quotient of stimulated and primary echoes. Using field cycling relaxometry, it has been shown that there is strong evidence of reptation-like motion, even for such short-chain polymers as shown by the frequency and molecular weight dependences of the spin-lattice relaxation time.
authors.affiliation: Sektion Kernresonanzspektroskopie, Universität Ulm, 89069 Ulm, Germany. ravinath.kausik@uni-ulm.de
authors.forename: Ravinath
authors.initials: R
authors.lastname: Kausik
authors.forename: Nail
authors.initials: N
authors.lastname: Fatkullin
authors.forename: Nicola
authors.initials: N
authors.lastname: Hüsing
authors.forename: Rainer
authors.initials: R
authors.lastname: Kimmich
mesh_terms: D004058:Diffusion; D004987:Ethers / Q000737:chemistry*; D005466:Fluorocarbons / Q000737:chemistry*; D005898:Glass; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008956:Models, Chemical; D049329:Nanostructures; D036103:Nanotechnology / Q000379:methods; D011108:Polymers / Q000737:chemistry*; D016062:Porosity; D013997:Time Factors
chemical_list: D004987:Ethers; D005466:Fluorocarbons; D011108:Polymers; C078113:perfluoropolyether