Spreading Dynamics of Droplet Impact on a Wedge-Patterned Biphilic Surface
Round 1
Reviewer 1 Report
In general a good and interesting paper in promising reserach field.
However, what is good can always be improved, some suggestions for improvement:
1) Formating of equation, some errors appear.
2) I am missing the coupling between experiments and modeling, for example with the VOF approach. Please add a short discussion
3) Consitency, why "et al" for some references, while full name are written out for other references?
4) References are missing for Table 1.
5) Finally, improve the clarification on the uniqness of this paper-
Author Response
Dear Reviewer,
Thank you for you hard work and please find the attachment.
Any further comment is welcomed.
Regards,
Yanjie Yang
Author Response File: 
Author Response.pdf
Reviewer 2 Report
This paper explains the spreading dynamics of a droplet impacting on wedge patterned biphilic surface with the help of experimental results and some simple model slightly modified from the existing literature. In this paper the authors also try to present the variation of maximum spreading ratio with respect to the Weber number and apex angle. The amount of work presented here meet the minimum requirement of publishing, however the overall presentation and discussion of the results should be improved. My comments are given below:
First of all, authors should check their manuscript properly for the mathematical symbol. Throughout the paper there are lots of mathematical symbols which are missing from the equation. Surprisingly it has been started from very beginning of the abstract. Authors should pay closer attention to the box signs in the manuscript which should be replaced by '~' symbol, I believe.
1st two sentences of the abstract seems similar to me. They should be converted to one.
Line 29, 40, 50, 60, 79,102, 108,146,152,135,239 and many more. Authors should pay better attention to these mistakes. In many places the word 'vibration' has been used incorrectly. it should be replaced by the word 'oscillation'. In line 108 and 152, the word 'separately' should be replaced by 'respectively'.
Another main concerns , perhaps the most serious concern in this paper is that , all the experimental results are presented without the ERROR BAR. It is mandatory , otherwise the repeatability or the validity of the experimental results are dubious. I highly recommend the authors to add error bars.
line 129-130 should be supported by appropriate reference.
In fig3 and 1st inset, what is indicated by the arrow?
I did not understand the the statement in line 140 and 141, ' Fig4 shows that.......varies with time'. What is meant by the close velocity and the whole discussion should be clarified properly.
Inconsistency in writing D_0 (line 144-145).
Line 233 , what is meant by proper Weber number?
In line 257, authors claimed that the for low We, the droplet spreads linearly but i cannot see any linearity in Fig 8. this issue should be addressed properly.
It seems that the figure 9 and 10 represent the results calculated from the mathematical equation. Why not also add the experimental results in the same plot to represent the deviation of theory from the experiment ?
In many places author have used the word 'rebound'. In general rebound means the droplet bouncing but I cannot see any droplet bouncing phenomena in Figure 3, 5,7. I believe the appropriate word should be recoiling of the droplet. However, if the authors want to use the word rebound then they have to explain it properly , exactly what does it mean.
At the end i would highly recommend to change the conclusion. As the conclusion is written in a superficial way. Specially, the first two bullet points is not a novel results or finding anymore, rather it becomes a commonsense in the droplet impact study.
Author Response
Dear Reviewer,
Thank you for your hard work and please find the attachment.
Any further comment is welcomed.
Best Regards,
Yanjie Yang
Author Response File: Author Response.pdf
Reviewer 3 Report
The authors studied the effect of apex angle and tilting angles on spreading dynamics of droplet impact on solid surface experimentally. They developed the maximum spreading factor using contact angle between a surface and the droplet deposited on the surface and dimensionless numbers followed by the experimental verifications of its superiority. Finally they experimentally obtained the relation between the maximum spreading factor and Weber number. The topic is within the scope of the applied sciences. The problem formulation for mathematical modeling is well defined, and final results are promising. However, there are some points needed to be resolved:
1. There are some typos, awkward sentences, and symbols having different font size throughout the manuscript. Please carefully check the manuscript.
2. Please clarify □ mark throughout the manuscript.
3. “Though the mechanisms of droplet impact have been researched abundantly, many detailed issues still remain unknown....” Please explain what issues have not been studied and why the issues have to be studied in detail with the necessity of your study.
4. Please explain how you coated the hydrophobic polymer particle on the hydrophilic silicon surface with the coating method and conditions in detail.
5. “The transportation properties along the wedge patterned surface are studied somewhere else using the force balance and energy conservation.” please add the reference on the sentence.
6. Please explain the terms used in this study (e.g. apex angle, advancing edge, and receding edge) using a schematic.
7. Please explain Fig. 4 in detail (e.g. x and y axis, legends...)
8. In Eq. (2), when it reaches the maximum diameter, the shape of the droplet is similar with the hemisphere not the cylinder. I think that a constant k that can be experimentally or empirically determined is needed to compensate the difference between the actual shape of the droplet deposited on the surface and the droplet shape you assumed for the modeling.
9. In Eq. (4), the units of the left and right side formulas seem to be different. Please check and modify Eq. (4) and the equations related to Eq. (4) if there is typo.
10. Please explain Fig. 7 in detail.
11. Please improve the resolution of Fig. 8(e). The figure is quite blurred.
12. To emphasize the maximum spreading factor you developed, I recommend putting Figs. 9 and 10 in one figure as Fig. 9(a) and (b).
13. Please summarize the conclusion more concisely.
Author Response
Dear Reviewer,
Thank you for your hard work and please find the attachment.
Any further comment is welcomed and please inform me freely.
Best Regards,
Yanjie Yang
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
Authors have implemented all the suggestions and revised (mainly deleted the questionable sentences) the manuscript.
I am happy to suggest for publication with minor revision, still, there are some sentences which are awkward and difficult to understand.
Author Response
Dear reviewer,
Thank you for your kind consideration for the revised version and the minor revision decision.
English has been polished by an experienced editor this time and 53 corrections have been made to make it easier to understand.
Please find the track changes in the revised version.
Best regards,
Yanjie
Reviewer 3 Report
The revised manuscript have been modified sufficiently according to the comments that I gave them and now it could be published in the journal. Thank you.
Author Response
Dear reviewer,
Thank you for your kind consideration for the revised version and the minor revision decision.
English has been polished by an experienced editor and 53 corrections have been made in the revised version this time.
Please find the track changes in the revised version.
Best regards,
Yanjie
This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.
