A =
4m
D
(2)
where D is the mean fibre diameter and is the fibre density.
Therefore,
S =
4
D
(3)
The density of the nanofibre mat was calculated by using the
mass of the mat in air (m1) and in n-hexane (m2) through the
following equation:
= (m1h
)/(m1− m2) (4)
where his the density of n-hexane at the temperature of mea-surement.The porosity of the membrane (ε) is obtained by using
the equation:
ε =
Vtot − V
Vtot
(5)
where Vtot is the total (apparent) volume, obtained by measuring
the area and the thickness of the mat, and V is the volume, calculated
from measured mass and density of the nanofibrous membrane