VOLDIS: A Direct Search for the Size Distribution of Nanoparticles from Small-Angle Scattering Data and Stability of the Solution

Round 1

Reviewer 1 Report

The authors present a very intriguing study. This work can be published after some minor updates:

Line 432: Regarding data processing with ATSAS package, please describe all details and steps for the data reduction process.

Line 435: As authors carefully compare and analyze the particle size results from different methods, a set of high-resolution transmission electron microscopy (TEM) from Ludox TM50 silica particles is needed to better understand particle size distribution and the aggregation behavior of these particles. The TEM data would be an essential complement.

General points: English language and style need a minor re-writing and paraphrasing.

Author Response

Line 432: Regarding data processing with ATSAS package, please

          describe all details and steps for the data reduction process.

=> See lines 456-460.

 

Line 435: As authors carefully compare and analyze the particle size

          results from different methods, a set of high-resolution

          transmission electron microscopy (TEM) from Ludox TM50 silica

          particles is needed to better understand particle size distribution

          and the aggregation behavior of these particles.

          The TEM data would be an essential complement.

=> Experiments on the electron transmission microscope are planned and started now.

   The results will be presented in a future publication. Obtaining the "right"

   size of nanoparticles is more difficult than it may seem at first glance.

   The problem is that the dilution of the initial 30% solution of LUDOX TM-50 with

   distilled water is accompanied by some aggregation of the particles due to a

   decrease in pH and the concentration of Na+ ions (see Chapt. 2.3 in the

   manuscript). When using a stabilizing 0.06M NaOH solution and drying a drop of

   solution on a preparative grid, the NaOH concentration increases, which can

   lead to partial dissolution of the silica surface and decrease the apparent

   size of the particles. Finding optimal conditions (perhaps the use of a

   surfactant to stabilize the particles will be tested) will take some time.

   The results of these experiments will be published in a separate article.

 

General points:

   English language and style need a minor re-writing and paraphrasing.

=> Some phrases were corrected.

Reviewer 2 Report

Dear Dr Volkov,

Thank you for submitting the manuscript.

This is a solid piece of work but requires some modifications before I suggest accepting it.

My comments are the following:

1. Paragraph starting on Line 37: I would change the numbering, and use a) b) c) instead of (1) (2) and (3). The existing enumeration can be confused with equation numbers.

2. Line 63: Statement "particles of unit density" shall be reinforced, that is a crucial condition/limitation of the technique.

3. Line 78: "particle shape can be chosen: spheres, ellipsoids... "

One shall present a link to a working code placed on GitHub or some platform of a similar kind. The entire paper talks about a method applicable to the study of complex systems, giving an example of the spheres only. It shall give a reader a way to test the algorithms. I apologize if I've missed the references.

4. Line 95: "The arguments of the target function are the values ..." please insert the reference to the equation number for the target function.

5. Line 110: please add estimations for Dmax used by the algorithm for other shapes. Please describe how Dmax is chosen for a form-factor provided by a user.

6. Line 116: reference [10] looks strange to me in there. If indeed it is correct, the reference shall specify a corresponding chapter. Just [10] is very generic.

7. Line 122: "therefore" is not needed.

8. Line 123 can be rephrased into the following:

"... calculated from a smoothed distribution contour additionally improving the conditionality of the problem."

9. Line 124: the sentence starting from "Solutions are searched ..." is not clear and needs to be rephrased.

10. Line 142: "numbers", not a "number".

11. Line 142: the sentence "A nonzero lower value is set using information about the nature of the sample." needs some examples clarifying what the author has meant by it.

12. Line 161: a reference to the full description of the algorithms is required.

12. Equation (7): it is not clear what J is. Please define it.

13. Line 178. I apologize if I am missing the obvious, but one shall add a reference to the program DN2FB code.

14. Line 235: in the "... program provides for ..." - "for" is not needed.

15. Line 243: "too different" is better to be replaced by "highly variable"

16. Line 245: It is not clear what is meant by the "rule (5,6)". Please clarify.

17. Line 249. "... curve can be limited to 200-300." is better to be replaced by "... curve can reach values as high as 300"

18. Line 276 is not clear, please rephrase.

19. Lines 371-274: this is a bit of a repetition of what has been said earlier. Again, here one shall add a reference to the code, to let readers to try the code.

20. Line 400: Superscript 2 at Chi is not placed correctly.

21. Line 413: the sentence " and the scattering angle region corresponded to a range of scattering vector modulus values of 0.1 < s < 10.0 nm-1" might be better placed later, as following:

"The sample-detector distance was 700 mm for AMUR-K and 280 mm for HECUS covering 0.1 < s < 10.0 nm-1 and  ... for each of the instruments, respectively".

22. Paragraph 2.2: please add a value for the sample thickness.

23. Line 419: again, reference [10] is very generic here. Please add a reference to a chapter.

24. Line 424: it is not clear what the "electrical double layer" is. Please rephrase.

25. Link 425: A sentence starting from "When diluted with distilled water ..." is not needed, this is a repetition of the one just before.

26. Line 432: A reference is incorrect.

27. Figure 1. Perhaps a zoomed insert for the high Q data might be useful.

I would recommend adding a Conclusions part summarising the applicability of the proposed method. Also, Supplementary material demonstrating the use of the software would be very beneficial for the readers adding more practical value to this work.

Author Response

The author is very grateful for the constructive and valuable comments,

which allowed to significantly improve the presentation.please see the Attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Thank you for the revision.