Wear-Resistant Hydrophobic Coatings from Low Molecular Weight Polytetrafluoroethylene Formed on a Polyester Fabric
Round 1
Reviewer 1 Report
This manuscript discussed about some hydrophobic coatings for polyester fabrics and made the comparison. The work has some practical industry use and has potential to improve. I will suggest authors consider all these questions below.
(1) The title and main text talk about "low molecular weight" , is molecular weight important for the work and why?
(2) I suggest the abstract and conclusion should focus some sentences about the significance and novelty for this work. Hydrophobic/superhydrophobic coating by PTFE is commonly used. What is the motivation for the authors to work on it?
(3) Figure 1 needs to be improved and wavenumber/unit needs to be rewritten correctly.
(4) Figure 2 does not have the un-coated fabric SEM so it is not easy for comparison, only see relative smooth fabric surface. Could the author include that?
(5) For Figure 4,5, some fonts are too small, difficult to see the dimensions. Also please directly point out specific sub-image and explain in the main text. Starting form line 248 could be explained more in detail.
(6) Could authors have some discussion comparison for the coating stiffness before Table 3 so readers have better understanding for the concepts for the stiffness numbers.
Author Response
Dear reviewer!
Thank you for your very helpful questions and comments. We have tried to make the required changes to the article.
Point 1. The title and main text talk about "low molecular weight", is molecular weight important for the work and why?
Response 1: Conventional high molecular weight polytetrafluoroethylene is absolutely insoluble in all known solvents. Therefore, when we mention solutions of polytetrafluoroethylene, we immediately clarify that we are talking about a low molecular weight fraction of polytetrafluoroethylene. In the article we indicate that polytetrafluoroethylene is insoluble (lines 69-70, in red)
Point 2. I suggest the abstract and conclusion should focus some sentences about the significance and novelty for this work. Hydrophobic/superhydrophobic coating by PTFE is commonly used. What is the motivation for the authors to work on it?
Response 2: We thank the respected reviewer for a valuable remark. Suggestions regarding the novelty and importance of the work are included in the abstract and conclusions (lines 8, 13-14, 19-20,302-305, 323-325, in red).
Fluorine-containing compounds with a higher surface energy than PTFE are commonly used as water repellents to form a hydrophobic/superhydrophobic coating. This is due to the fact that the application of PTFE to the fabric until now was considered technologically impossible. However, it is preferable to use a water repellent with the lowest surface energy. Therefore, methods for obtaining low molecular weight PTFE recently developed by a number of researchers and the results of studying its solubility were prerequisites for using PTFE in our work. In the article, the reasons for using low molecular weight PTFE as a water repellent are substantiated in the lines 69-70 (red font).
Point 3: Figure 1 needs to be improved and wavenumber/unit needs to be rewritten correctly.
Response 3: We have improved and replaced Figure 1.
Point 4: Figure 2 does not have the un-coated fabric SEM so it is not easy for comparison, only see relative smooth fabric surface. Could the author include that?
Response 4: We have added an image of uncoated fabric to Figure 2.
Point 5: For Figure 4,5, some fonts are too small, difficult to see the dimensions. Also please directly point out specific sub-image and explain in the main text. Starting form line 248 could be explained more in detail.
Response 5: We have enlarged Fig. 4,5 to show the dimensions. We have also referenced figures in the text and added a histogram for TFE telomer coverage.
Point 6: Could authors have some discussion comparison for the coating stiffness before Table 3 so readers have better understanding for the concepts for the stiffness numbers.
Response 6: We have tried to explain in more detail the concept of stiffness (lines 268-274, in red).
Author Response File: 
Author Response.docx
Reviewer 2 Report
The manuscript does not have enough novelty to publish in scientific journals. The quality of the figures should be improved. Figure 1 must be redrawn using appropriate software. The manuscript in current format is not acceptable.
Author Response
Point
The manuscript does not have enough novelty to publish in scientific journals. The quality of the figures should be improved. Figure 1 must be redrawn using appropriate software. The manuscript in current format is not acceptable.
Response
Dear reviewer!
Unfortunately, you do not provide evidence of the lack of novelty in the article, which makes it difficult for us to respond to this serious remark. However, we want to draw your attention to the fact that the article analyzes completely new methods for obtaining hydrophobic coatings. They are formed on the basis of low molecular weight polytetrafluoroethylene which no one else has been able to use yet. The coatings take on the properties of polytetrafluoroethylene rather than its higher surface energy derivatives. In addition, we use a fundamentally new approach to obtaining coatings: the deposition of low molecular weight polytetrafluoroethylene from solutions in non-traditional solvents. Perhaps we did not write clearly enough about the novelty in the article. Therefore, additional suggestions regarding the novelty and importance of the work are included in the abstract and conclusions (lines 8, 13-14, 19-20,302-305, 323-325, in red).
To improve the quality of the text, it was edited by a professional translator.
We have tried to improve the quality of the drawings. Figure 1 has been redrawn.
Author Response File: Author Response.docx
Reviewer 3 Report
1- The method and apparatus used for obtaining the IR spectra shown in Fig. 1 are not described in section 2.
2- The quality of fig. 1 is low. Similar fonts and sizes should be used in both images. The same problem exists in figure 3.
3- Figure 2, an image showing the raw fibers is also required. Images with higher magnification are recommended.
4- The captions of figure 2 and 4 should contain the type of the images i.e., SEM, AFM, …
5- The numbers in fig 4 cannot be read. Figure 4c needs units for the axes.
Author Response
Dear reviewer! Thank you for your questions and comments!
Point 1- The method and apparatus used for obtaining the IR spectra shown in Fig. 1 are not described in section 2.
Response 1. We have added to section 2 a description of the method and apparatus for obtaining IR spectra (lines 152-154? In red)/
Point 2- The quality of fig. 1 is low. Similar fonts and sizes should be used in both images. The same problem exists in figure 3.
Response 2. We have remade the Figure 1 and have corrected the font in Figure 3.
Point 3- Figure 2, an image showing the raw fibers is also required. Images with higher magnification are recommended.
Response 3. We have replaced Figure 2 on high magnification images and added a raw fabric image.
Point 4- The captions of figure 2 and 4 should contain the type of the images i.e., SEM, AFM, …
Response 4. We have added types of images to captions of Figures 2 and 4.
Point 5- The numbers in fig 4 cannot be read. Figure 4c needs units for the axes.
Response 5. We have increased the size of figures 4 and 5 in order to read the numbers and the units of the axes.
Author Response File: Author Response.docx
Reviewer 4 Report
The manuscript by Prorokova et al. discusses about the wear resistance of fibres covered by Teflon-like polymers. This is a topic that is fairly well studied, but it has considerable interest in the scientific point of view. The paper presents interesting data, but I mean that it at the present state is shallow to allow publication in Colloids and surfaces A. I offer some comments below that the authors may want to consider for publication:
1.- authors should change figure 1 and improve the quality of the FTIR characterization.
2.- authors should increment the amount of cycles for wear resistance and ageing in wettability.
Author Response
Dear reviewer!
Thank you for your valuable comments!
Point 1.- authors should change figure 1 and improve the quality of the FTIR characterization.
Response 1. We have remade the Figure 1.
Point 2.- authors should increment the amount of cycles for wear resistance and ageing in wettability.
Response 2. Table 2 presents data for an increased number of cycles of operational impact on the fabric.
Author Response File: 
Author Response.pdf
Round 2
Reviewer 1 Report
The authors have revised the work and I could see the input. I only suggest the newly added Figure2A still needs to be revised to fit for 2b and 2c. Now I could not see scale bar for 2b. The bottom of 2a needs to be fit for other 2 figures. Also "The study method scanning electron microscopy" is not a sentence. Line 189-190 needs to explain the difference from figure 2abc, not only 2 sentences.
Author Response
Dear reviewer!
Thanks for your helpful comment.
Point.
The authors have revised the work and I could see the input. I only suggest the newly added Figure2A still needs to be revised to fit for 2b and 2c. Now I could not see scale bar for 2b. The bottom of 2a needs to be fit for other 2 figures. Also "The study method scanning electron microscopy" is not a sentence. Line 189-190 needs to explain the difference from figure 2abc, not only 2 sentences.
Response:
We reworked Figure 2 a, b, c and added explanations of this Figure to the text (lines 189-192, in red)
Author Response File: Author Response.pdf
Reviewer 2 Report
The authors did not carefully attend to the reviewer comments and the revison is insufficient to guarantee publication in scientific journals. Hence, I can not recommend the publication of manuscript.
Author Response
Point
Moderate English changes required
The authors did not carefully attend to the reviewer comments and the revision is insufficient to guarantee publication in scientific journals. Hence, I cannot recommend the publication of manuscript.
Response
Dear reviewer!
Our manuscript was reviewed and edited by a native English speaker.
Author Response File: Author Response.pdf
Reviewer 3 Report
Accept
Author Response
Point.
English language and style are fine/minor spell check required
Response.
Our manuscript was reviewed and edited by a native English speaker.
Author Response File: Author Response.pdf
