An evaluation of nano-order pore size of membranes was carried out using pe
rmporometry, the basic principle of which is based on capillary condensatio
n of vapor and the blocking effect of permeation of a non-condensable gas.
A computer-controlled apparatus was constructed, where liquid was injected
by a syringe pump and nitrogen was used as a carrier, and was applied to th
e evaluation of the pore size of ceramic membranes prepared from a silica-z
irconia composite. The pore size distribution, based on the Kelvin equation
(Kelvin diameter), was evaluated over a range of 0.5-30 nm, using water as
a condensable vapor. Vapors used in the present study were water, methanol
, ethanol, isopropanol, carbon tetrachloride, and hexane. For the case of r
elatively large pore sizes (larger than 1 nm, based on water vapor), pore s
ize distribution obtained by water vapor agreed very well with those by car
bon tetrachloride and hexane. However, pore sizes measured using alcohols w
ere found to be smaller than those determined by water vapor. For the case
of pore sizes smaller than 1 nm, the adsorption layer before capillary cond
ensation appears to play an important role. (C) 2001 Elsevier Science B.V.
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