Fluoropolymer Film Formation by Electron Activated Vacuum Deposition

Round 1

Reviewer 1 Report

The paper by Grytsenko and co-workers entitled ‘Fluoropolymer Film Formation by Electron Activated Vacuum Deposition’ describes an exciting new development of fluoropolymers films that consist of sub-micron features were produced by decomposition-evaporation of bulk fluoropolymers in vacuum. The results show that the deposited fluoropolymer films composed from mainly linear macromolecules with small quantity of crosslinks, instead of highly crosslinked plasma “polymers”. The study appears to be of a very high quality: the manuscript is very well written, free from jargon, and easily understandable. The figures have also been assembled and prepared with great care. I recommend this manuscript for publication, but suggest that the following minor points are considered first: There are many reports out describing Fluoropolymer Film Formation by electron cloud, also for optoelectronic and photonic devices application. What is the major improvement of your system?

Author Response

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Reviewer 2 Report

The manuscript discusses fluoropolymer film formation by electron activated vacuum deposition. The authors compared the growth of different types of fluoropolymers thin film deposited compared to the bulk structure and the mechanical properties.

The growth mechanism and its relation to the fragments obtained from the MS results and structural analysis using IR could have been explained in more detail. Also he aim of comparing those 3 types of polymer in particular would help in explaining the merit of this work.

There are some minor/moderate English language revision that could also help in improving the manuscript. Also using "." instead of "," is recommended for decimal numbers and "^o" instead of "⁰" in expressing ^oC.

Author Response

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Reviewer 3 Report

The authors of this manuscript are reporting on fluoropolymer film formation by electron activated vacuum deposition. Keeping in view the importance of fluorpolymer films in the field of science and technology especially protective coatings, dielectric layers and matrix for nanocomposites, the work is interesting and lies within the scope of Surfaces. But there are several shortcomings in the manuscript which must be addressed before its publication in Surfaces.

My comments to the authors are following

 Title:

The title is oversimplified.  It will be more attractive if it contains the name of polymers i.e. Polytetrafluoroethylene, polyhexafluoropropylene and polychlorotrifluoroethylene

Abstract:

The authors write “ Atomic force microscopy has revealed different growth mechanisms for PTFE, PHFP and PCTFE”

Incorporation of name of mechanisms is suggested.

Introduction:

Provide reference for “Recently the method of evaporation-activation of the PTFE film deposition (EVD) 

was developed”

Highlight novelty of the work by writing comprehensive problem statement.

The authors write “The aim of this work is to research on the whole chain of the fluoropolymer film deposition in  vacuum: decomposition-evaporation of the fragments of macromolecules, composition of the gas phase during activation, growth, structure and the properties of the films”

It would be better to specify the properties you are interested to study.

 

Experimental:

 

Please write molecular weights of the polymers studied i.e. PTFE, PHFP and PCTFE” in the revised manuscript.

 Write detail about recording IRS

 

Results  

 

 Mass-spectra which were recorded during PTFE deposition with activation by accelerated electrons with various voltage  120 and constant film deposition rate 2 nm/sec.

It should be 2 nm/s   rather than 2 nm/sec.

Fig. 4a. The IRS provided seems to be smoothed.  It would be better to provide the originally recorded spectra for clear comparison.

Usually major bands in the IRS are provided in Tabular form with proper assignments and references.

 

Discussion

Please write valid reason for “ Activation led to an increase of relative concentrations of CF₃⁺ and C₃F₅⁺ and decrease of CF⁺ and C₂F₄⁺ fragments”

For the investigated polymers, film formation is assumed to follow a polymerization process which could be radical, ionic or both. Hence, the active species are either neutral radicals which carry a magnetic moment or radical ions.

Do you have any proof for this statement though you did not carry out mechanistic investigation?

 The AFM studies showed, that the Volmer-Weber mechanism was responsible for perfluoropolymer film growth, whilst the formation of the PCTFE film was due to the Frank - van der Merwe mechanism. 

 Do only AFM studies enough to decide about the type of mechanism?

Specify the type of dyes. Didn’t dye degrade during AFM spectra recording?

 

 

Author Response

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Round 2

Reviewer 3 Report

The manuscript has been revised in the light of earlier comments and seems suitable for publication in Surfaces