Effects of Polydopamine Incorporation on the Nanostructure and Electrochemical Performance of Electrodeposited Polypyrrole Films

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript entitled ”Effects of Polydopamine Incorporation on Nanostructure and Electrochemical Performance of Electrodeposited Polypyrrole Films” by James A. Behan * , Frédéric Barrière describes the preparation and characterization of PPY/PDA film.

I would recommend the manuscript for publication due to the nice work and good presentation of the results. I cannot see the drawbacks.

 

One thing that I would suggest to add more electrochemical properties of the PPY/PDA layer is to perform the impedance experiments and the calculation of electron transfer rate constant.

 

Author Response

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Reviewer 2 Report

Comments and Suggestions for Authors

The authors report about the electrochemical deposition ofPPY-PDA films, analyzing the influence of PDA on the deposition rate of the films and their optoelctronic properties.

The methodology is sound and the work is well presented. However, I find the results already known to the scientific community and this work does not add significant information to early studies such as : Electrochemical deposition of conductive and adhesive polypyrrole-dopamine films | Scientific Reports (nature.com)

Here a few additional comments:

- One of the reason why the authors include PDA is that it should improve the films adhesive properties. However, they do not test nor discuss them in the text (however, it is quite known in the literature)

- In Fig. 5 and discussion: I would like to see also the PDA spectroscopic analysis for comparison. Why the authors consider that PDA has such a little influence? Is it the case or it is a combination of PDA properties with Raman spectroscopy?

- The authors investigated the films morphology by AFM and XPS, which only account for the surface composition and morphology of the films. They conclude that the morphology of PDA-PPY films is different from PPy films, but at the same time have a "PPy-like structure". The supporting discussion is not clear and should be improved.

I suggest the publication of this work after revision, only if the authors can prove the novelty of their results compared to existing literature. 

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The manuscript reports the synthesis and characterization of PPy/PDA films through electropolymerization. The most interesting results are monitoring the film formation kinetics, and thickness with the eQCM technique. However, the manuscript is full of unclear/incorrect use of terms and inconsistent use of abbreviations. The manuscript before being considered for publication the comments below must be addressed.

-Why do the Authors refer to PPy/PDA films as "conductive carbon", "carbon scaffold", "carbon electrode", and "carbon nanostructures", explain!

-In the "preparation of PPy, PDA and PPy-PDA films" part, add the exact synthesis conditions of pyrrole and dopamine concentrations, and how they were dissolved/dispersed in the buffer solution.

- Explain why the authors used neutral conditions for the preparation of electroconductive films.

-What do you mean by using DA as a “co-dopant” (line 149)?

-Add all used techniques to the characterization part e.g., profilometry.

- Both profilometry and eQCM results however show an increase in deposition of the PPy/PDA films compared to PPy, they do not show double the thickness. Double-check the values of the film thickness calculated by profilometry and eQCM.

-Explain why frequency shift vs time (Fig 2a and b) shows steps like behaviors, not gradual increase as shown in FigS1 b.

-The authors didn’t explain why the film growth rate in the composite was higher than that of pristine PPy.

-AFM images show smother PPy-PDA film compared to PPy film, profilometry results have different opinions about that. explain why there is a contradiction. 

-Why there is an increased level in the C=N peak in FTIR of PPy-PDA, and the same XPS results also explain the existence of the O-C=O peak in XPS, based on the chemical structures in Scheme 1?

-Please correct the values of peak positions on Raman spectra.

-Tuac plots show a little decrease in Eg band of the composite, explain.

-Please add the conductivity measurements of electroconductive PPy and PPy-PDA films to the manuscript.

Comments on the Quality of English Language

Moderate editing of English language required, little typos.

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

I thank the authors for their replies and this new version.

I still find the novelty quite limited, but I am satisfied with their replies.

As follow up comment, I would change "nanostructure" in the title and through all the text, with "microstructure". The AFM investigation does not allow to see the nanoscale, rather the microscale.

I find it suitable for publication after minor revision.

none

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

-   I'm afraid I have to disagree with the naming of the carbon electrode since there was no graphitization process, also there was no scaffold formed, only thin films.

-  Please add the reason for choosing a neutral pH condition to the manuscript as described in your response, not only that it took place under mild and biocompatible conditions.  

-  Again, I am afraid to disagree with the use of co-monomer, there is no copolymerization was proved there, I suggest removing it to be written as “PPY deposition in the presence of DA was first investigated…”.

 

- please rename the electro-synthesized films to "PPy/PDA films"

- Please remove "co-monomer" , Line 158.

Author Response

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Author Response File: Author Response.pdf