Dear Ümran Aşçı

There are a number of ways by which we can calculate the porosity of Nanofibers. Some of the techniques are SEM, TEM and BET Analysis. You can calculate NF porosity via SEM image using imageJ software, the same way you calculate the diameter of the Nanofibers. But, I would recommend BET Analysis to calculate porosity of the Nanofibers. Brunauer–Emmett–Teller (BET) theory aims to explain the physical adsorption of gas molecules on a solid surface and serves as the basis for an important analysis technique for the measurement of the specific surface area and porosity of materials. The observations are very often referred to as physical adsorption or physisorption. I hope this would help you

https://www.sciencedirect.com/topics/engineering/brunauer-emmett-teller-method

I agree with Ankush Sharma

It is very difficult to accomplish an accurate determination of porosity via electron microscopy. You can view the samples and realize how porous they are. But numerical determination is difficult. BET on the other hand is the most widely accepted technique for porosity and effective surface area determination for nanomaterials.

BET is the most widely accepted technique for nanomaterials.

Dear Ümran Aşçı,

(BET) surface area analysis is the multi-point measurement to determine the specific surface area (m2/g) through gas adsorption analysis. You can calculate approximate porosity from SEM micrographs by using ImageJ software. It is a free software

Hi dear Ümran Aşçı .

I recommend you to check your major reference that is similar to your current work and do the same as they did, but the usual way is calculating by ImageJ software.

Dear all, various techniques are followed to accomplish such a task. Please check the following documents. My Regards

https://www.researchgate.net/publication/287468448_A_Novel_Method_for_Measurement_of_Porosity_in_Nanofiber_Mat_using_Pycnometer_in_Filtration

https://doi.org/10.1155/2012/327369

Ankush Sharma Souvik Bhattacharjee Saad Zahraw Sekhi Vishal Gavande Mahyar Saber Abdelkader BOUAZIZ thank you for your valuable replies.

If your sample contains a large size pore (micron size) then you can try Mercury intrusion porosimetry. If your sample is nanoporous in nature then you can try volumetric adsorption methods (you can use either N2 or Ar as an adsorbent). For the analysis of adsorption data, you can use the BET method (for mesoporous materials). But if your sample contains micropore together with ultramicro pore then you can use the alfa S method for analysis. TEM and SEM can give you a rough general idea regarding the porous nature of the sample.

Directly, by electron microscopy, I think it is not possible. If the pores are very large (and you can see them) you can make an estimate, but the result you get will not be very valid ...