Stability of the Photoluminescent Response on Hydroxyapatite/Multi-Walled Carbon Nanotube Composites

Round 1

Reviewer 1 Report

This paper studies the stability of the photoluminescent response on hydroxyap- 2 atite/multi-walled carbon nanotubes composites. It may provide sufficient information for related studies. Therefore, it can be published after revision:

(1)    The images should be improved. The authors need to download a published article on materials science to learn how to design the images.

(2)    It is suggested that the author should perform a reaction to show the material is useful.

fine

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

The paper investigated the photoluminescence properties of hydroxyapatite/multi-walled carbon nanotubes functionalized with oxygen group composites. The amount of OMWCNT and the treatment temperatures were varied to measure the photoluminescence spectra when the sample is prepared and after one year of preparation. The presentation of the results and the introduction needs to be improved to meet the publishing standards.

1.       In the abstract and introduction, the authors stated that the motivation of the study is that despite the extensive use of HAp/MWCNT in medical applications, their photoluminescence properties are under-studied. The logic flow switching from medical to optoelectronic applications is not clear. What would be the advantage of using HAp/MWCNT in light emission as mentioned in line 41 over conventional LED? The authors need to improve the introduction to have a meaningful motivation for the proposed research.

2.       An example of a misleading statement is on line 61 ‘In this new use of HAp, CNT can be useful in the medical area as well because they have been employed to make organic light-emitting diodes’.Why CNT is needed for OLED? MWCNT can be metallic, which will quench the photoluminescence, which is consistent with the later results where the photoluminescence intensity decreased after adding OMWCNT. I would encourage the authors to improve the statements over the whole manuscript for it to be more specific and accurate.

3.       The author stated that ‘Comparing the results of each sample in the original and the second measurement, 317 the intensities differed by a factor of four between HAp250 Figure 7a and c. In the case of 318 HAp400, Figure 7b and d the gap was about 2 times.’ Is there any reference sample being used to calibrate the system over one year? Can we confirm that the increased intensity is from the sample itself instead of the instrument condition at different times?

4.       It is better if the authors clarify on line 150 that ref 19 is their previous publications so that the comparison is more reliable because the parameters are controlled.

5.       Although the authors have mentioned that two parameters were tuned in the experiments, they still should define what the label 'HAp250-15' means.

There are some misleading statements in the introduction that need the authors' attention. Some examples are given in the review comments.

Author Response

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Author Response File: Author Response.docx

Reviewer 3 Report

Comments for author File: Comments.pdf

Nil

Author Response

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Reviewer 4 Report

1)    "The calculation of nanocrystal size via XRD (Figure 1) should be done
by referring to
doi:10.3390/nano10091627"

2)    The design of the synthesis route should be carried out.

3)    Why do you have SEM, but there is no EDAX analysis?

4)    Please explain a clearer XRD interpretation, especially that beta calcium phosphate may be present,

5)    The "Conclusions" section should be expanded.

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Author Response

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Round 2

Reviewer 2 Report

The authors have responded to all of my comments and made corresponding revisions to the manuscript. I recommend accepting it in its present form.

Reviewer 3 Report

Authors revised this manuscript very well.  The current version of manuscript looks good. Accept it.