Translation and Rotation of Penetrants in Ultrapermeable Nanocomposite Membrane of Poly(2,2-bis(trifluoromethyl)-4,5-difluoro-1,3-dioxole-co-tetrafluoroethylene) and Fumed Silica

Autor:	Wen Yang Wen, Scott D. Kelman, Alan A. Jones, Junyan Zhong, Guoxing Lin, Benny D. Freeman
Rok vydání:	2005
Předmět:	Molecular diffusion Nanocomposite Polymers and Plastics Cyclohexane Chemistry Diffusion Organic Chemistry Analytical chemistry Fick's laws of diffusion Inorganic Chemistry Diffusion layer chemistry.chemical_compound Polymer chemistry Materials Chemistry Tetrafluoroethylene Fumed silica
Zdroj:	Macromolecules. 38:3754-3764
ISSN:	1520-5835 0024-9297
DOI:	10.1021/ma047880c
Popis:	Diffusion of pentane, cyclohexane, and toluene in nanocomposite films of fumed silica and poly(2,2-bis(trifluoromethyl)-4,5-difluoro-1,3-dioxole-co-tetrafluoroethylene) is observed by pulse field gradient NMR. The apparent diffusion constant determined in this experiment depends on the time over which the diffusion measurement is made. The pure copolymer and the nanocomposites based on it are inhomogeneous materials phenomenologically similar to a porous system with the fast diffusion domains having an apparent pore size in the micron size range. In this regard the diffusion can be considered to be anomalous with slopes as low as 0.6 in plots of the logarithm of mean-square displacement vs the logarithm of time at short observation times and at lower silica content. The slower diffusing toluene and cyclohexane are influenced to a greater extent by the inhomogeneous structure when motion is considered over the same time. The addition of nanoparticles increases the diffusion constants of the penetrants subs...
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::8034187003685cd4a83bad67f578e762 https://doi.org/10.1021/ma047880c Zobrazit plný text záznamu