Eur. Phys. J. E 2, 117-123
Porous structure of membranes of an acrylonitrile copolymer. Porosity, 1H-NMR permeability
Laboratoire de Spectrométrie Physique, Université
J. Fourier, CNRS, BP 87, 38402 Saint Martin
d'Héres cedex, France
Annie.viallat@ujf-grenoble.fr
Received 8 July 1999
Abstract
Nanoporous polymer membranes (porosity
)
used for dialysis are studied from NMR relaxation times of
water confined in the pore space. Fast interpore water diffusion
is observed. Two structural parameters are evidenced: i) a
reduced NMR relaxation time, 
,
which reflects the width of
the pore-size distribution; ii) the average polymer-grain size of
the solid matrix deduced from NMR experiments performed on
membranes partially filled by water. A relation is found between
the ratio 
,
where k is the permeability to water and
the porosity. This relation is in qualitative agreement with
numerical simulations reported in the literature on low-porosity
systems and with experimental results obtained for sedimentary
rocks and for fused glass model systems. It supports the idea
that
is the relevant structural parameter to describe
convective transport in a wide class of porous systems.
PACS
81.05.Rm Porous materials; granular materials
- 76.60.Es Relaxation effects
- 47.55.Mh Flows through porous media
Copyright EDP Sciences, Società Italiana di Fisica, Springer-Verlag
