How to select the q range to find fractal dimension using power law in SAXS analysis?
Is it the high q range where Porod law (I=B+C * q^-4) is applicable or the middle range where there is a steep decrease in I(q) value?
Hi Akash G. Nathani....... I am not really understand your question fully as its too general. But, from my experience what can i suggests you that fractal dimension can be mass fractal or surface fractal. In a log-log plot of intensity verses q vector you might get mass fractal oe surface fractal or both depends on how your material was processed and what it contains. I suggests you to consider a book written by Otto Glatter, Otto KratkyOtto Glatter, Otto Kratky...You will definitly learn a lot from this. Hope that will help you.
Hello Imran,
Thank you for your reply. I understand that in the log-log plot of intensity versus q vector if the slope (alpha) lies between 3-4 than the material is surface fractal with D= 6-alpha and if alpha lies between 2-3 than the material is mass fractal but in am not sure about selecting the range for log(q). At very high log(q) values the slope becomes ~4 (porod region).
I am studying porous polymer fibers. At the middle range the of log(q) value, the slope of Log-Log plot is lying between 3-4 (surface fractal) for the non-porous fiber samples (same material) and for porous fibers it is lying between 2-3 (mass fractal), I am not able to understand what could be the physical meaning of it.
Also can you please explain how could we know if the material is both surface and mass fractal.
HI Akash G. Nathani.....Thats right what you mentioned but what exactly you think about surface and mass fractals?I mean in terms of real physical meaning. I think if you understand fractals in general than you are able to explain micro structure. Fractals system are the complex form of Euclidean or Topological dimension. The explanation is given on the basis of fractal theory coupled with your particular interest. "iInterest" means what is your material and what exactly you want to determine. Ok, in short, the exponet between 2 and 3 rapresents mass fractal systems or networks continuity. This can be pores network, or continuous material with some pores. The fractal 4 is used for smooth surfaces while 3-4 for rough surfaces. I think there are also some comes interface effects which at the moment i dont remember .......In near future one of my paper will be published and you can get some information. Its not exactly what you are studying but i guess you can understand at least fractals nature. I can check how long it will take to publish, otherwise i can send you the draft.Where did you performed such experiments?......hope thats help you.....
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