Enhancement of the Surface Hydrophilicity of Poly(Vinyl Chloride) Using Hyperbranched Polylysine with Polydopamine

Round 1

Reviewer 1 Report

Manuscript Number: coatings-2794826 

Title: Polydopamine-assisted modification of hyperbranched polylysine on poly(vinyl chloride) for enhanced surface hydrophilicity    

Coatings

         After reading your manuscript, I think the topic is relevant for the journal and several experiments are included. This article shows some promise for publication. To justify the publication of this work a Major improvement has to be made in terms of the following remarks:

• The wording must be improved throughout. The authors should work with an English-speaking colleague and consider resubmission only after a careful edit.
• The title of the article is not suitable. It needs to be rewritten.

·         The abstract's last part should discuss the main results with numbers and values obtained from the tests.

·         Please also be sure that your abstract and your Conclusions section not only summarize the key findings of your work but also explain the specific ways in which this work fundamentally advances the field relative to prior literature.

·         Introduction: In the last paragraph, the authors have tried to depict the aims of their study. However, the novelty of the work is not highlighted. What is new here?

·         Experimental: The purity of all used products should be added.

·         The room temperature should be noted in the manuscript, for example, 23±2 °C.

·         Figure 2: How can we relate the apparent color changes of the samples to their surface morphology?

·         Line 259: The claim that the accumulations on the surface are related to pDA needs to be confirmed with additional tests.

·         Figure 3: Graphs should be inserted in color. Black and white graphs have not been used in articles for years.

·         Figure 4: Images of the contact angle of a water droplet with the sample surface must be included. The left and right contact angles of the droplet on the image should be indicated.

·         In the contact angle review section: The results must be compared and confirmed with other research. Overall, the discussions and results in section 3 of the article need more references.

·         The most scientific part of the paper is its discussion section. The correct discussion should compare the result of your study with other similar studies.

• The wording must be improved throughout. The authors should work with an English-speaking colleague and consider resubmission only after a careful edit.
•  

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

The purpose of the work consists in the surface modification of PVC films with the combination of hyperbranched polylysine (HBPL) and polydopamine (pDA) through either simultaneous deposition with polydopamine (PVC-pDA/HBPL) or successive deposition of pDA and HBPL (PVC-pDA-HBPL), aiming to investigate the influence of the modification method on surface hydrophilicity enhancement.

 As stated by the authors, this study presents a promising approach, inspired  by mussel adhesion protein, for hydrophilic modification of PVC surfaces in order to ensure its safety for biomedical applications.

 In my opinion, the quality of the current manuscript is high in terms of characterizations performed and perspectives, average in terms of process explanations and readibility.

Here some specific comments/remarks:

1) Line 21 – Misprint: Roman spectroscopy

2) Line 48 - I can't find "bussal gland" in the anatomy of th blue mussel. Is it a misprint?

3) Figure 2 - The quality of the SEM images is not high: a better contrast should be employed to better enhance the differences among the samples. It would have been interesting also having a roughness estimation of the four different samples, that surely plays a role in the interaction among surface molecules.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

The remarks are included it the attached file

Comments for author File: Comments.pdf

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The authors of the article have thoroughly examined most of the questions and suggestions, but the response to Comment 9 in the first stage of review is not convincing!

Comment 9: As the esteemed authors of the article are aware, the AFM test is not used to identify compounds. The reviewer’s question is how do you confirm that these particles and aggregates are of pDA type. Certainly, to confirm this opinion, tests such as XPS or EDS are needed.

Author Response

Thank you sincerely for dedicating your time to reevaluate this manuscript once again and for providing invaluable comments and suggestions, which are crucial in enhancing the quality of the current manuscript. Kindly find below a detailed response along with corresponding revisions highlighted in red for easy comparison in the resubmitted files.

Comment: As the esteemed authors of the article are aware, the AFM test is not used to identify compounds. The reviewer’s question is how do you confirm that these particles and aggregates are of pDA type. Certainly, to confirm this opinion, tests such as XPS or EDS are needed.

Response: I apologize for the lack of clarity in my previous response and sincerely appreciate your valuable suggestion. Following your recommendation, we have supplemented the EDS data for PVC film and PVC-pDA particles, as depicted in Figure 2e. The presence of the nitrogen signal observed in the PVC-pDA results indicates that the predominant constituents are pDA aggregates.

Reviewer 3 Report

It is difficult to evaluate the revised version of the manuscript because a letter with the authors' responses is not available for the reviewer(s). As tracking the highlated changes in a manuscript some comments have been addressed but still the authors do not show the direct and well founded evidence of the reaction between pDA and  HBPL deposit itself and PVC surface.

What more the provided new data about roughness Rq (fig. 3 and corresponding paragraph) sugests that this is a profile roughness that is not defined and showed in presented images. The area roughness parameters, e.g. Sa, Sq give more significant values are more representative in case of such layers

Author Response

Thank you sincerely for dedicating your time to reevaluate this manuscript once again and for providing invaluable comments and suggestions, which are crucial in enhancing the quality of the current manuscript. Kindly find below a detailed point-by-point response along with corresponding revisions highlighted in red for easy comparison in the resubmitted files.

Comments 1: It is difficult to evaluate the revised version of the manuscript because a letter with the authors' responses is not available for the reviewer(s). As tracking the highlated changes in a manuscript some comments have been addressed but still the authors do not show the direct and well founded evidence of the reaction between pDA and  HBPL deposit itself and PVC surface.

Response 1: It is possible that the issue stems from system malfunctions. I apologize for the inconvenience caused by your inability to view my reply attachment. In the attached document, I have re-uploaded my response to the initial set of comments. Regarding the reaction between pDA and HBPL during deposition, we can speculate that the interaction between PDA and HBPL possibly occurs through a Schiff base bond based on the observed changes in surface infrared, Raman spectra, and contact angle. Furthermore, an approximate verification of our conjecture can be obtained by examining the structure of the reaction products formed by DA and HBPL in solution. However, it should be noted that these aforementioned results only provide some insights into the potential interaction between these two components. To gain a comprehensive understanding of their specific reaction characteristics and bonding properties, further detailed investigations are required in future studies.

Comments 2: What more the provided new data about roughness Rq (fig. 3 and corresponding paragraph) suggests that this is a profile roughness that is not defined and showed in presented images. The area roughness parameters, e.g. Sa, Sq give more significant values are more representative in case of such layers.

Response 2: Thank you for your highly relevant guidance. The roughness parameters have been substituted with area roughness parameters of Sq. 

Author Response File: Author Response.pdf