Hydrophobic Material: Effect of Alkyl Chain Length on the Surface Roughness
, Mochamad Zakki Fahmi 1,2, Satya Candra Wibawa Sakti 1,2, Titah Aldila Budiastanti 1 and Tri Esti Purbaningtias 3Round 1
Reviewer 1 Report
The manuscript title “Hydrophobic Material: Effect of Alkyl Chain length on The Surface Roughness” was reported by Widati et al. sol gel deposition of SiO2-TiO2-alkylsilane was analysed by the different spectroscopy techniques. Furthermore, SiO2-TiO2-OTMS membrane was employed the surface studies. I suggested comments below;
1. Could you explain the absence of TiO2 peaks in XRD results?
2. The overall quality of the figures has increased.
3. Figure 4, Could you explain the FTIR spectrum of different SiO2 and TiO2 amounts? I didn't see any differences in the peaks.
4. What is the optimal SiO2 and TiO2 coating surface combination? Could you suggest another application?
Author Response
Dear Editor and Reviewer,
We appreciate for the corrections and great suggestion from reviewers. We have revised our manuscript based on the reviewer’s feedback. Please see the attachment. We hope you can give us the opportunity to follow the further process to publish in JMMP.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The authors investigated the effects of alkyl chain length on the surface roughness and the development of hydrophobic material. Three different types of alkylsilane with varied chain length: methyltrimethoxysilane (MTMS, 95%), octyltrimethoxysilane (OTMS, 96%), and hexadecyltrimethoxysilane 82 (HDTMS, 85%) were used, respectively. The effects of composition and chain length on the hydrophobicity, coating technology, stability of the coating and anti-dirt performance was investigated. However, there are some specific comments bellow:
1. The authors proposed using three different alkylsilane to modify SiO2 and TiO2, and studied the effects of chain length and layer number on hydrophobicity. However, the relationship between the hydrophobicity and roughness was not given and lack of sufficient discussion. The contribution of surface roughness on hydrophobicity should well discussed.
2. Many characteristics of the fabricated coatings were studied while the title of the manuscript is the effects of alkyl chain length on the surface roughness. What is the critical concern of this study?
3. The authors should give more details of the coating technology. How to control the on-layer deposition and the layer-by-layer deposition. How many layers were deposited onto the substrate?
4. In fig. 3 the roughness value should be given and more profound discussion on hydrophobicity should be given.
5. Fig. 9a shows the effects of alkylsilane chain length on the hydrophobicity, the value of water contact angles is not corresponding with the trend of column. 140.67º±1.23º is lower than that of 102.95º±2.27º.
Overall, the current version of the manuscript looks chaos, the authors should focus on the key points and give profound discussion. The novelty of this study should be well illustrated.
The manuscript should give major revision for further consideration.
Author Response
Dear Editor and Reviewer,
We appreciate for the corrections and great suggestion from reviewers. We have revised our manuscript based on the reviewer’s feedback. Please see the attachment. We hope you can give us the opportunity to follow the further process to publish in JMMP
Author Response File: Author Response.pdf
Reviewer 3 Report
The Authors report on the results regarding preparation of the hydrophobic surface. The glass surface was modified using nanoparticles (SiO2 and TiO2) and alkylsilane of various alkyl chain length. In this way, Authors prepared hydrophobic surfaces of various roughness, what resulted in various contact angles. In my opinion, the data described by the Authors are interesting, however the manuscript suffers from serious flaws. In revised version it is necessary to address the following issues for further consideration for publication:
1) The manuscript should be checked by person fluent in using English language.
2) Please check the references carefully, as there are some mistakes, see page 7, lines 203-204: “…Ramirez-Garcia and colleagues also reported that the use of SiO2-203 TiO2 increased the adhesion of coatings [7].” – but paper of Ramirez-Garcia et al is listed as [12] in References.
3) Page 3, lines 114 and 118: “ …at room temperature (33°C)…” – Are You sure it is 33??
4) In general, there are almost no information about particles, at least sizes of synthesized particles should be delivered.
5) Page 3, line 122: “…The contact angle of the coated glasses were measured using ImageJ software.” – should be ‘was’. But there is an additional issue. As the Authors use imageJ then it should be specified the exact method of contact angle measurement: did they use one of the commonly available macro for imageJ (if yes, then please add info about that)? Or they measured it manually? Or maybe they write their own macro, in this case they should specify what kind of algorithm or function they applied to fit the drop shape and find the contact angle.
6) Page 3, line 128: “…The stability of coatings were studied by measuring the change of water contact angle under outdoor exposure for one month...” and whole paragraph Stability of coatings – I understand that there is no standard procedure to study stability of such modified surfaces, but in my opinion this kind of experiment should be planned and performed in the way that it can be repeated (with the same surfaces or even different surfaces) in other laboratories all over the world for comparison. Instead, potential reader is getting some data which cannot be properly analyzed. What does it mean ‘outdoor exposure’ ? What was the weather, temperature, etc. ? This whole paragraph does not make sense for me.
7) Page3, line 129: “…The performance of anti-dirt property was evaluated using CuCl2.2H2O as an artificial dirt…” – more details please, how data presented in paragraph 3.5. Anti-dirt performance of coatings were obtained? How the accumulate dirt was estimated? Figure 15 – Y-axis, the amount of dirt on the surface [%], what does it mean? Is this percentage of total surface? Can Authors please give more details on the reason of choosing CuCl2 for this test?
8) Figure 2 – if You change the amount of the only one substrate (X-axis) then please add information about the amount of the other two substrates in description under the figure. Same problem with Figure 3, please add those data.
9) Figure 4 - the differences between 15 mmol and 30 mmol are so small that it might be better to show 7.5 mmol and 30 mmol, instead.
10) Figure 7 – same issue in here, and based on data from Figure 6, choosing 15 mmol and 30 mmol for comparison does not make sense, as even contact angle is very similar for those conditions. 7.5 mmol insteed 15 mmol might be better choice.
11) Figure 6 – Did Authors really measure contact angle for surfaces prepared without alkylsilanes? And got contact angle equal zero??? As I remember even clean glass gives contact angle ca. 2‑4!!
12) Figure 9a – there is something wrong with the bars. Why the highest bar is described with ca value 102.95, and the lowest one has 126.18. Please correct this.
13) In general, please expand paragraph 2. Materials and Methods – Characterization. All presented method are scarcely described, for example, AFM – add details on the tip and modes, some info about used software for AFM data treatment would be useful.
In my opinion this manuscript needs major revision before publication.
Author Response
Dear the Editor and Reviewer,
We appreciate for the corrections and great suggestion from reviewers. We have revised our manuscript based on the reviewer’s feedback. Please see the attachment. We hope you can give us the opportunity to follow the further process to publish in JMMP.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The authors modified the manuscript well based on the review comments.
Author Response
We appreciate the time and efforts by the editor and referees to review this manuscript. Thank you so much for your suggestion and correction.
Reviewer 2 Report
I didn't find the responses for the following questions:
3. The authors should give more details of the coating technology. How to control the on-layer deposition and the layer-by-layer deposition. How many layers were deposited onto the substrate?
4. In fig. 3 the roughness value should be given and more profound discussion on hydrophobicity should be given.
5. Fig. 9a shows the effects of alkylsilane chain length on the hydrophobicity, the value of water contact angles is not corresponding with the trend of column. 140.67º±1.23º is lower than that of 102.95º±2.27º.
Author Response
We appreciate for the corrections and great suggestion from reviewers. We have revised our manuscript based on the reviewer’s feedback. Herein, we prepared our manuscript based on marked color. We give the purple color for the revision as reviewer’s suggestions. Please see the attachment. We hope you can give us the opportunity to follow the further process to publish in JMMP
Author Response File: Author Response.pdf
Reviewer 3 Report
I have no additional questions.
Author Response
We appreciate the time and efforts by the editor and referees to review this manuscript. Thank you so much for your suggestion and correction.
