Surface Modification of Polyethersulfone (PES) with UV Photo-Oxidation

Round 1

Reviewer 1 Report

The manuscript under the title: “Surface Modification of Polyethersulfone (PES) with UV Photo-Oxidation” is relevant to Technologies journal. The authors selected an important topic connected with modern polymer technologies. The article based on experimental research. The structure is typical for research articles, but the text required some improvements before the publication, i.a.:

• Abstract: “Hg lamps” - please use full name in abstract.
• Abstract: please clearly articulated the main aim of the research,
• Figure 1: “three kinds of C” – please add the legend / description with particular names.
• Introduction: please stress the gaps in the state-of-art and stress the novelty of provided research.
• Materials: Could you provide some properties declared by manufacturer?
• Surface topography: The more detailed description for AMF is required.
• Discussion: The comparison with up-to-date literature is rather poor (!). The all received results should be discussed.
• Conclusions: What about possibilities of practical applications?
• References: quite limited the number of references; lack of references for the investigation made in 2020.

Author Response

The abstract now includes the word "mercury' instead of Hg and more clearly shows the aims of the research by emphasizing the need to "oxidize the surface of PES and increase hydrophilicity". 

Clarifications to the legend of Figure 1 were made to show the different types of bonding.

The Introduction section emphasizes the need for XPS and functional group detection to help fill the gap for chemical analysis of the modified PES surface.

Thickness and catalog number are now given for manufacturer's PES material.

A more detailed description of AMF is provided.

New references 17-24 were added to the Discussion section describing up-to-date literature about practical applications for water purification.

Reviewer 2 Report

Thank you for the opportunity to review the article entitled Surface Modification of Polyethersulfone (PES) with UV Photo-Oxidation. The article is written correctly, but I have some comments about it. The article will be suitable for publication in the Technologies journal after taking them into account. My comments are presented below.

1. I suggest changing the markings on the figure (e.g. use different colors).
2. Authors should extend the Discussion section or consider combining it with the Results section.
3. Equations 2-9 should be ordered and standardized (e.g. centered).
4. There are typos in the text of the article which must be corrected.

Author Response

1. Instead of focusing on the color for the XPS images, the arrows in the Figures greatly help with showing the changes with treatment time.
2. By adding the new references 17-24 to the Discussion section about recent water purification studies, there is now more of a difference between the Discussion and Results sections indicating the need for both sections.
3. Equations 2-9 are now more ordered and centralized.
4.  The manuscript was carefully reread and some corrections for typos mistakes were made.

Reviewer 3 Report

This report deals with UV-photo-oxidation of PES membrane surfaces. The following issues need to be addressed prior to publication:

1. Figure 1 is pixelated, and has distorted ("squeezed") rings. Please redraw it, keeping bond lengths and angles accurate, and upload a high res image.
2.  The chemical equations need to be properly typeset.
3. For the identification of potential UV oxidation products, can an oligomeric form of PES (with 2 or 3 units, say) be studied and the products identified? This may serve as a control.
4. Please attach the contact angle measurement camera images in the SI.
5. Figure 2 is almost incomprehensible. Break it up into sub-graphs, with contact angle data as a function of treatment time being plotted separately.
6. Would FTIR of the surface of the films be useful in proving some of the chemical structure modifications hypothesized?

Author Response

1. The size of Figure 1 was decreased and the legend now more clearly defines the different types of bonding.
2. The chemical equations have been reset and centralized.
3.  Future research will be needed to study different oligomeric forms of PES.
4. Only the contact angle data were collected and no camera images were stored.
5. The different symbols in Figure 2 clearly identify the changes in at% and contact angle.
6. This study primarily focused on XPS analysis for chemical modification which found not much difference between 253.7 nm and 253.7/184.9 nm treatment. References [5,15] previously studied FTIR measurements for 253.7 nm treatment of PES. Since we did not observe major differences between the two photo-oxidation techniques, we did not feel a need to do FTIR measurements of 253.7/184.9.

Round 2

Reviewer 1 Report

The article entitled: "Surface Modification of Polyethersulfone (PES) with UV Photo-Oxidation" has been revised. The most of the necessary changes are implemented. The article requires only slights improvements:

• Figure 6 requires more detailed comments.
• The discussion with the literature should be more detailed, including differences and similarities between the presented research and up-to-date articles.

Author Response

1. A more detailed description of the results from Figure 6 has been added to the revised manuscript.

2. The Discussion section now includes more information as to how our UV photo-oxidized PES results may be coupled together with recent publications involving graphene oxide and sulfonated functioned groups, as well as polymerized dopamine and nanocellulose, to increase the hydrophilicity of PES and enhance water purification; and