According to the SEM images obtained for NiO-PBT nanocomposite
(Fig. 3a) and PBT nanofibers (Fig. 3b), some characteristic
features including high surface area and porous structure
make NiO-PBT nanocomposite coating a rather suitable candidate
for extracting VOCs such as toluene, ethylbenzene, o-xylene and
m-xylene compounds. As Fig. 3c reveals, the NiO-PBT nanocomposite
coating film is homogeneous along the stainless steel
wire and the NiO-PBT nanocomposite diameters are in the lower
than 400 nm along with possess very porous structure (Fig. 3a).
Also, interestingly a layer of much narrower fibers is observable in
NiO-PBT nanocomposite in compared with PBT nanofibres (Fig. 3a
and b). Certainly these features make the NiO-PBT nanocomposite
very porous which favors the increased surface area, adsorption
sites availability and higher mass transfer for analytes during the
sorption/desorption steps. The presence and disperse of NiO
nanoparticles in whole coating increases the spaces among the
nanofibers in which much faster analytes diffusion in PBT network
is more probably facilitated.