Can anybody help me to find what kind of pores (whether mesoporous , blind , etc) of the PANI-ZnS. I must mention that "with the increase of ZnS contents more than 30 wt% (Fig. d), the composites transform in morphology from typical fibrous PANI to predominant ZnS particles". Is that right? How can I explain this Figures?
30% is rather high concentration.. explain your images in terms of "percolation".. and SEM is not a good method to explain porosity.. ..BET adsorption is better method.
I agree with the above comment. From SEM images, you may be able to roughly say your samples are porous. But if you want to clearly show the effect of ZnS content on pore size, surface area, of pore volume of the PANI-ZNS, you may need to use N2 adsorption using BET method.
Can you re-upload your SEM images? We can't open it.
Dear Hojjat Amrollahi Bioki,
SEM study gives the information about surface morphology of the samples and it does not provides the information about porosity.I agree with the comments of Sridhar and Mirabbos. You should perform BET measurement on your samples for porosity information. Also, BET and BJT are those methods which provides detailed information about sphefic surface area, pore diameter and pore volume of samples.
Dear brother,
when you go for SEM analysis, you have to keep cursor between two ends of the pore and you can mark the pore size. As NOVA 450 SEM, i already used give you clearly the pore sizes in the SEM image.
Another option is BET surface analysis, you can get pore size , pore volume and BET surface area. But for BET, it is very difficult to get the accurate pore size of macroporous materials.
Kind regards
Gowhar
i tnink AFM better than SEM
BET is the better technique for determine pore size
The scattering techniques like SAXS and SANS could be useful techniques for porosity measurements.
I was not able to open the photos, but anyway:
a) PAni does not really have fibrous morphology, fibrils are in any case only a secondary morphology form built from globular primary particles (which are about 10 nm in size); you can see in my literature on RG
b) in order to meaure porosity (= open accessible inner surface), BET is the best method (as already mentioned), however, I need to add a comment: the PAni surface can not well be measured that way, for unknown reasons, BET gave us always at least 1 order of magnitude too low values; it looks to me as if nitrogen does not adsorb on the PAni surface.
I also wanted to comment on Sridhar's comment about "percolation":
"percolation" only happens or its theory can only be applied in systems which are in thermodynamic equilibrium and the system components are statistically evenly distributed; this means, that every smallest volume unit looks the same as another one.
However, nanoparticle systems are far far far from equilibrium, they always inevitably form thermodynamic non-equilibrium systems, and are formed in far-from-equilibrium processes.
This is why we never see "percolation" to happen, but a phenomenon which is characteristic for such non-equlibrium systems: chaotic behaviour, formation of "dissiptive structures" (cf Prigogine's basic theory, I have made one for dispersions based on his theory)
First of all, it is not so clear to distinguish PANI from ZnS in those SEM images. Maybe you should present a range of SEM of your samples with the conc. of ZnS from 0% (only PANI) 10%, 20%, 30% and only ZnS (100%). Then you can say about "the transform in morphology". I do not have experience with ZnS NPs SEM images but I did with PANI, and from your SEM images, to me, it looks like your PANI "melting".
Hope this help and have a nice day!
http://www.nature.com/nmat/journal/v3/n11/full/nmat1242.html
Dear Bernhard,
Please take a look at one of the article on Pani welding or melting, it is an interesting phenomenon!
sorry, I can not read the whole article, only the abstract (can you send a pdf?)
Anyway, "welding" is not equivalent with "melting"! Melting would involve the polyaniline chains to become disorganized, become a fluid, the original primary particles of the material (10 nm in size, you can check my publication in RG) would become "destroyed", a homogeneous melt / fluid develops, then when cooling down below melting point, a new morphology would have formed and the primary particles would have been gone.
In "welding", this does not happen.
In fact, I have made myself some welding process and found out that the resulting formed articles has no different electrical properties than a film cast from dispersion:
https://www.google.com/patents/US4925610
PAni does not melt at all.
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