Synthesis, Characterization, and Antibacterial Potential of Poly(o-anisidine)/BaSO4 Nanocomposites with Enhanced Electrical Conductivity
, Sohail Nadeem 2,*, Raya Soltane 3,4, Mohsin Javed 2, Shahid Iqbal 5,*, Zunaira Kanwal 1, Muhammad Fayyaz Farid 1, Sameh Rabea 6, Eslam B. Elkaeed 6, Samar O. Aljazzar 7, Hamad Alrbyawi 8 and Walid F. Elkhatib 9,10
Round 1
Reviewer 1 Report
Referee report on manuscript “Synthesis, Characterization and Antibacterial potential of Poly(o-anisidine)/BaSO4 Nanocomposites with Enhanced Electrical Conductivity “ by Mirza Nadeem Ahmad et al
The authors report the results of their studies of antibacterial effects of composites made of Poly(o-anisidine) and BaSO4. This is a rather interesting topic, which, of course, is needed in the development and promotion, the results that are obtained are interesting and can be accepted for publication after a more detailed disclosure of some ambiguities and uncertainties.
1. Line 46-53. to attract a wider readership, it is recommended to specify the relevant composite compounds more specifically, so that it would be visible immediately in the text, and not in the list of references. Herewith it is important to mentioned a few of them, relevant to this study:
Karbovnyk, I.; et al. The impact of temperature on electrical properties of polymer-based nanocomposites. Low Temp. Phys. 2020, 46, 1231–1234.
Aksimentyeva, O.I.; et al. Modification of polymer-magnetic nanoparticles by luminescent and conducting substances. Mol. Cryst. Liq. Cryst. 2014, 590, 35–42.
Tsebriienko, T.; Popov, A.I. Effect of Poly(Titanium Oxide) on the Viscoelastic and Thermophysical Properties of Interpenetrating Polymer Networks. Crystals 2021, 11, 794.
2. It would also be useful to indicate what other applications of BaSO4 already exist and it is possible that this study will open up new opportunities there as well. See for example:
https://scholar.google.com/scholar?hl=en&as_sdt=0%2C5&q=BaSO4&btnG=
3. Please check the last line of Table 1.
4. Figure 2. The quality of the drawing is clearly insufficient because the details are hard to see. Furthermore, please use arrows to indicate the main peaks and their interpretation.
5. Figure 3. The quality of the drawing is clearly insufficient because the details are hard to see.
6. Table 2. Indicate the error bar for conductivity and describe it in more detail in the text.
7. Table 3. The title “size of inhibition zones of inhibition (mm)” needs correction, because of the repetition.
Author Response
Reviewer 1
Referee report on manuscript “Synthesis, Characterization and Antibacterial potential of Poly(o-anisidine)/BaSO4 Nanocomposites with Enhanced Electrical Conductivity “ by Mirza Nadeem Ahmad et al
The authors report the results of their studies of antibacterial effects of composites made of Poly(o-anisidine) and BaSO4. This is a rather interesting topic, which, of course, is needed in the development and promotion, the results that are obtained are interesting and can be accepted for publication after a more detailed disclosure of some ambiguities and uncertainties.
Comment 1. Line 46-53. to attract a wider readership, it is recommended to specify the relevant composite compounds more specifically, so that it would be visible immediately in the text, and not in the list of references. Herewith it is important to mentioned a few of them, relevant to this study:
Karbovnyk, I.; et al. The impact of temperature on electrical properties of polymer-based nanocomposites. Low Temp. Phys. 2020, 46, 1231–1234.
Aksimentyeva, O.I.; et al. Modification of polymer-magnetic nanoparticles by luminescent and conducting substances. Mol. Cryst. Liq. Cryst. 2014, 590, 35–42.
Tsebriienko, T.; Popov, A.I. Effect of Poly(Titanium Oxide) on the Viscoelastic and Thermophysical Properties of Interpenetrating Polymer Networks. Crystals 2021, 11, 794.
Response. Thanks for valuable suggestion. The modification and references have been incorporated as per recommendation of reviewer and highlighted in Turquoise.
Comment 2. It would also be useful to indicate what other applications of BaSO4 already exist and it is possible that this study will open up new opportunities there as well. See for example:
https://scholar.google.com/scholar?hl=en&as_sdt=0%2C5&q=BaSO4&btnG=
Response. The changes have been incorporated as per direction of reviewer and highlighted in Yellow.
Comment 3. Please check the last line of Table 1.
Response. The correction has been made and highlighted in Gray.
Comment 4. Figure 2. The quality of the drawing is clearly insufficient because the details are hard to see. Furthermore, please use arrows to indicate the main peaks and their interpretation.
Response. The Figure 2 has been improved as per instruction of reviewer.
Comment 5. Figure 3. The quality of the drawing is clearly insufficient because the details are hard to see.
Response. The figure 3 has been improved as per instruction of reviewer.
Comment 6. Table 2. Indicate the error bar for conductivity and describe it in more detail in the text.
Response. Thanks for valuable suggestion. Actually, the conductivity data was directly measured from conductivity meter which was already calibrated for error.
Comment 7. Table 3. The title “size of inhibition zones of inhibition (mm)” needs correction, because of the repetition.
Response. The correction has been made and highlighted in Dark Yellow.
Reviewer 2 Report
The topic of the study is interesting, considering the nanocomposite system is not so usual, and it could have some potential applications in different fields. However, the way the manuscript has been structured and presented requires a deep reformulation, otherwise it cannot be accepted.
Firstly, the manuscript should be thoroughly reviewed because there are many typos and mistakes in general. For instance, the name of the bacteria is Staphylococcus aureus, and not Staphylococcus ureus.
There are strange expressions, such as “nonmaterial” (page 1, line 30), or many apparently meaningless sentences, such as “The polymeric materials are packed employing different non-living compounds to improve temperature as well as impact opposition, and mechanical strength,…”. I suppose the authors meant something like “Polymeric materials used in packaging applications contain inorganic compounds to improve temperature resistance and impact strength” (page 3, line 82). Another example: “Overall, the opportunity along with potential proves to exist excellent through the resulting nanocomposite materials” (page 3, line 90). These examples suggest that the manuscript has been automatically translated from another language, and it should be reviewed to become understandable.
Regarding the introduction, the examples given do not have a clear link to the nanocomposite system studied in the paper. The authors present a general description of the importance of polymer nanocomposites, including topics such as biodegradability which have nothing to do with the system studied. Yet, nothing is presented regarding BaSO4 nanocomposites, nanocomposites based on electrically conductive polymers, or antibacterial properties, which are the topics covered in the experimental section.
The Materials and Methods section is incomplete. When presenting the materials used, nothing is explained, there is only a list of materials and compounds disconnected of the rest of the paragraph: “o-anisidine monomer, Ammonium persulphate [(NH4)2S2O8], Diaminodiphenylamine (DDPA), HCl/H2SO4, DI water, Barium Sulphate nanoparticles” (page 4, line 100). The authors mention barium sulphate nanoparticles on that list, but then on the following page they describe that the nanoparticles were actually synthesized on this study.
On the experimental section, the authors cite A and B, or solution A and solution/arrangement B, without clearly defining what these A and B are.
The characterization techniques / equipment used should be described in the Materials and Methods section, and not in the results.
The FTIR spectra should be replotted properly, instead of using the output curves of the equipment.
The UV-vis results have not been clearly interpreted for the nanocomposites.
No information about the size of the BaSO4 nanoparticles is given, to see if they are really in the nanoscale. At least some kind of microscopy analysis is expected.
Regarding the conductivity tests, it is not clear the purpose of adding insulating particles to an electrically conductive polymer. On page 8, line 220, the authors say that the increase of the amount of BaSO4 nanoparticles increased the conductivity of the system, which is not true, since the conductivity actually decreased.
The antibacterial properties are interesting, but they should be better connected to the other parts of the paper, to make it clearer what would be the main potential applications of the materials developed.
Author Response
The topic of the study is interesting, considering the nanocomposite system is not so usual, and it could have some potential applications in different fields. However, the way the manuscript has been structured and presented requires a deep reformulation, otherwise it cannot be accepted.
Response. The manuscript has been re-structured and revised as per reviewer demand.
Firstly, the manuscript should be thoroughly reviewed because there are many typos and mistakes in general. For instance, the name of the bacteria is Staphylococcus aureus, and not Staphylococcus ureus.
Response. The correction has been made throughout the manuscript and highlighted the Text.
There are strange expressions, such as “nonmaterial” (page 1, line 30), or many apparently meaningless sentences, such as “The polymeric materials are packed employing different non-living compounds to improve temperature as well as impact opposition, and mechanical strength,…”. I suppose the authors meant something like “Polymeric materials used in packaging applications contain inorganic compounds to improve temperature resistance and impact strength” (page 3, line 82). Another example: “Overall, the opportunity along with potential proves to exist excellent through the resulting nanocomposite materials” (page 3, line 90). These examples suggest that the manuscript has been automatically translated from another language, and it should be reviewed to become understandable.
Response. The text has been rephrased and correction as per instructions of reviewer.
Regarding the introduction, the examples given do not have a clear link to the nanocomposite system studied in the paper. The authors present a general description of the importance of polymer nanocomposites, including topics such as biodegradability which have nothing to do with the system studied. Yet, nothing is presented regarding BaSO4 nanocomposites, nanocomposites based on electrically conductive polymers, or antibacterial properties, which are the topics covered in the experimental section.
Response. The correction and modification has been made throughout the manuscript.
The Materials and Methods section is incomplete. When presenting the materials used, nothing is explained, there is only a list of materials and compounds disconnected of the rest of the paragraph: “o-anisidine monomer, Ammonium persulphate [(NH4)2S2O8], Diaminodiphenylamine (DDPA), HCl/H2SO4, DI water, Barium Sulphate nanoparticles” (page 4, line 100). The authors mention barium sulphate nanoparticles on that list, but then on the following page they describe that the nanoparticles were actually synthesized on this study.
Response. The correction has been made and reference has been incorporated as barium sulfate nanoparticles were synthesized by standard reported method.
On the experimental section, the authors cite A and B, or solution A and solution/arrangement B, without clearly defining what these A and B are.
Response. The clarification has been mentioned in the experimental section.
The characterization techniques / equipment used should be described in the Materials and Methods section, and not in the results.
Response. The changes have been made as per reviewer comment and highlighted in Pink.
The FTIR spectra should be replotted properly, instead of using the output curves of the equipment.
Response. The FTIR spectra has been improved as per instruction of reviewer.
The UV-vis results have not been clearly interpreted for the nanocomposites.
Response. The UV-visible spectra have been improved as per instruction of reviewer.
No information about the size of the BaSO4 nanoparticles is given, to see if they are really in the nanoscale. At least some kind of microscopy analysis is expected.
Response. The barium sulfate nanoparticles were synthesized by standard reported method and reference has been incorporated. The main focus was to discuss the antibacterial and conductivity properties of the materials
Regarding the conductivity tests, it is not clear the purpose of adding insulating particles to an electrically conductive polymer. On page 8, line 220, the authors say that the increase of the amount of BaSO4 nanoparticles increased the conductivity of the system, which is not true, since the conductivity actually decreased.
Response. The correction and modification has been made in the manuscript.
The antibacterial properties are interesting, but they should be better connected to the other parts of the paper, to make it clearer what would be the main potential applications of the materials developed.
Response. The modification has been made in the manuscript as per suggestion of reviewer.
Reviewer 3 Report
The manuscript entitled "Synthesis, Characterization and Antibacterial potential of Poly(o-anisidine)/BaSO4 Nanocomposites with Enhanced Electrical Conductivity" by Ahmad et al. describes the antibacterial effects of composites made of Poly(o-anisidine) and BaSO4 using Pseudomonas aeruginosa and Staphylococcus ureus. The study is not appealing in terms of novelty in my point of view. I do not recommend to consider this manuscript for publication.
Here are few points that are to be pondered upon:
1. The introduction section mentioned only the benefits of polymer-metal nanocomposites and their applications rather than about the previous studies undertaken with similar or different composites. The introduction section is highly considered to be general and every paragraph conveys same meaning.
2. Grammar and spelling errors are there. Many sentences are unnecessarily written and I do not find any relevance in their existence.
3. Why BaSO4 nanoparticles were synthesized from BaCl2, BaSO4 could have been used directly? What is the problem with that process.
4. Page 5, line 134 "and remove the other material from the polymer than dry it and the polymer comes in powder form" What is other material? and the polymer comes in powder form? only polymer is present now of BaSo4 nanoparticles are also present as this is the synthesis of composite.
5. Page 6, line 149. The present research work aims to synthesize the Poly (o-anisidine)/BaSO4 nanocomposite. Then why it is mentioned in abstract about antibacterial activity?
6. Page 6 line 163, the crystallinity of the poly(o-anisidine) matrix was increased with the addition of 1% BaSO4 as the peak appeared deeper and wider. Do add some reference to support your claim
7. Page 8 line 191, To locate the size, state of the nanoparticles and cooperation of nanoparticles with the encompassing matrix. How UV-Vis spectra can locate the size?
8. A separate section for mentioning the instrumentation should be added in place of writing it with the result and discussion.
9. Page 8 line 202-215 are highly irrelevant and just to increase the no. of words in the manuscript.
10. Fig. 3 is not edited properly. I recommend to edit.
11. The results and experimental techniques are insufficient to be published. It is recommended to add more characterization techniques.
12. PXRD, Raman, SEM, TEM of BaSO4 and POA/BaSO4 can be added to confirm the nanocomposite morphologies and crystal structure.
13. This type of nonconducting material uses to isolate the different electronic devices and wires. As the concentration of poly (o- anisidine)/BaSO4 nanoparticles increased, the conductivity of the nanocomposite decreased significantly. This line has been used more than 3 times in the manuscript.
Author Response
The manuscript entitled "Synthesis, Characterization and Antibacterial potential of Poly(o-anisidine)/BaSO4 Nanocomposites with Enhanced Electrical Conductivity" by Ahmad et al. describes the antibacterial effects of composites made of Poly(o-anisidine) and BaSO4 using Pseudomonas aeruginosa and Staphylococcus ureus. The study is not appealing in terms of novelty in my point of view. I do not recommend to consider this manuscript for publication.
Here are few points that are to be pondered upon:
- The introduction section mentioned only the benefits of polymer-metal nanocomposites and their applications rather than about the previous studies undertaken with similar or different composites. The introduction section is highly considered to be general and every paragraph conveys same meaning.
Response. The introduction section has been modified as per suggestion of reviewer.
- Grammar and spelling errors are there. Many sentences are unnecessarily written and I do not find any relevance in their existence.
Response. The correction and modification has been made in the manuscript.
- Why BaSO4 nanoparticles were synthesized from BaCl2, BaSO4 could have been used directly? What is the problem with that process.
Response. It is evident the nanomaterials have unique and better properties than their bulk materials. As mentioned in reference [45] and text highlighted in Green.
- Page 5, line 134 "and remove the other material from the polymer than dry it and the polymer comes in powder form" What is other material? and the polymer comes in powder form? only polymer is present now of BaSo4 nanoparticles are also present as this is the synthesis of composite.
Response. The correction and modification has been made in the manuscript.
- Page 6, line 149. The present research work aims to synthesize the Poly (o-anisidine)/BaSO4 nanocomposite. Then why it is mentioned in abstract about antibacterial activity?
Response. The correction and modification has been made in the manuscript. Actually, the antibacterial potential of the materials is significant and worth mentioning in this study.
- Page 6 line 163, the crystallinity of the poly(o-anisidine) matrix was increased with the addition of 1% BaSO4 as the peak appeared deeper and wider. Do add some reference to support your claim
Response. The correction and modification has been made in the manuscript.
- Page 8 line 191, To locate the size, state of the nanoparticles and cooperation of nanoparticles with the encompassing matrix. How UV-Vis spectra can locate the size?
Response. The barium sulfate nanoparticles were synthesized by standard reported method and reference has been incorporated. The main focus was to discuss the antibacterial and conductivity properties of the materials. Moreover, the interaction of nanoparticles with the matrix has been discussed in the results and discussion.
- A separate section for mentioning the instrumentation should be added in place of writing it with the result and discussion.
Response. The changes have been made as per reviewer comment and highlighted in Pink.
- Page 8 line 202-215 are highly irrelevant and just to increase the no. of words in the manuscript.
Response. The correction and modification has been made in the manuscript.
- Fig. 3 is not edited properly. I recommend to edit.
Response. The figure 3 has been improved as per instruction of reviewer.
- The results and experimental techniques are insufficient to be published. It is recommended to add more characterization techniques.
Response. Thanks for valuable proposition. As per your suggestion, it is shared that due to lack of testing facilities, we are unable to perform those tests in present situation.
- PXRD, Raman, SEM, TEM of BaSO4 and POA/BaSO4 can be added to confirm the nanocomposite morphologies and crystal structure.
Response. Thanks for valuable proposition. As per your suggestion, it is shared that due to lack of testing facilities, we are unable to perform those tests in present situation.
- This type of nonconducting material uses to isolate the different electronic devices and wires. As the concentration of poly (o- anisidine)/BaSO4 nanoparticles increased, the conductivity of the nanocomposite decreased significantly. This line has been used more than 3 times in the manuscript.
Response. The correction and modification has been made in the manuscript.
Round 2
Reviewer 2 Report
The paper has been only partially improved. Only some minor additions and partial language review have been provided, while a major revision was expected. The following points still must be considered:
- The English should still be reviewed. There were some local improvements, but there are still parts which need to be reviewed, especially in the abstract and the introduction.
- The introduction is still not suitable to explain the purpose of the study and the materials produced. The second paragraph on page 2 presents randomly selected nanocomposites, some of them based on conductive polymers, and others not. Usually, nanocomposites are classified into structural and functional. Structural nanocomposites focus on the improvement of mechanical properties by the addition of nanoparticles, while for the functional ones, the presence of nanoparticles adds extra functionalities to the polymer, such as electrical conductivity, special optical properties, antimicrobial features, and many more. In the case of conductive polymers, which have special functional properties by themselves, it is expected that nanoparticles would give extra features to the electrical or optical properties. The problem is that barium sulfate nanoparticles do not have a specific/special effect on the electrical properties of a polymer, so they are not able to increase its conductivity, but they end up decreasing it, just like any other regular insulating particle / nanoparticle would do. So, in this sense, these nanoparticles are not adding many useful features to the polymer, apart from the antimicrobial properties. Therefore, to make the purpose of the study clearer, the authors should improve the introduction, focusing more on the features of barium sulfate nanocomposites, citing more specific studies from the literature, instead of general, random information about polymers and nanocomposites.
- More information about the nanoparticles is still missing. A citation is only valid if it is from a previous study from the same authors, using the same experimental techniques to prepare the nanoparticles. One cannot call a material a “nanoparticle”, if not even some microscopic analysis has been made to prove the material has nanosized dimensions.
- The experimental conditions of the characterization tests were not included in the Methods section. There is no information about sample shape, size, amount, range of measurements, etc. The antibacterial activity tests should be described in the methods section, and not in the results.
- The FTIR and UV-vis graphs have not been updated at all. The captions and the fonts in general are too small, the FTIR graphs have the Bruker logo everywhere. The raw data should be replotted using origin, excel or another similar software.
- There is still no discussion about the UV-vis results for the nanocomposites. What is the point of including these graphs if nothing is said about them?
Author Response
Reviewer 2
The paper has been only partially improved. Only some minor additions and partial language review have been provided, while a major revision was expected. The following points still must be considered:
- The English should still be reviewed. There were some local improvements, but there are still parts which need to be reviewed, especially in the abstract and the introduction.
Response. Thanks for your valuable comments. The modifications have been addressed as per instruction of reviewer and highlighted in Green.
- The introduction is still not suitable to explain the purpose of the study and the materials produced. The second paragraph on page 2 presents randomly selected nanocomposites, some of them based on conductive polymers, and others not. Usually, nanocomposites are classified into structural and functional. Structural nanocomposites focus on the improvement of mechanical properties by the addition of nanoparticles, while for the functional ones, the presence of nanoparticles adds extra functionalities to the polymer, such as electrical conductivity, special optical properties, antimicrobial features, and many more. In the case of conductive polymers, which have special functional properties by themselves, it is expected that nanoparticles would give extra features to the electrical or optical properties. The problem is that barium sulfate nanoparticles do not have a specific/special effect on the electrical properties of a polymer, so they are not able to increase its conductivity, but they end up decreasing it, just like any other regular insulating particle / nanoparticle would do. So, in this sense, these nanoparticles are not adding many useful features to the polymer, apart from the antimicrobial properties. Therefore, to make the purpose of the study clearer, the authors should improve the introduction, focusing more on the features of barium sulfate nanocomposites, citing more specific studies from the literature, instead of general, random information about polymers and nanocomposites.
Response. The modifications have been addressed as per instruction of reviewer and highlighted in Teal.
- More information about the nanoparticles is still missing. A citation is only valid if it is from a previous study from the same authors, using the same experimental techniques to prepare the nanoparticles. One cannot call a material a “nanoparticle”, if not even some microscopic analysis has been made to prove the material has nanosized dimensions.
Response. Highly thankful for your valuable suggestion. TEM analysis has been performed and the results have added in the revised manuscript. Highlighted in Yellow.
- The experimental conditions of the characterization tests were not included in the Methods section. There is no information about sample shape, size, amount, range of measurements, etc. The antibacterial activity tests should be described in the methods section, and not in the results.
Response. The modifications have been addressed as per instruction of reviewer and highlighted in Pink.
- The FTIR and UV-vis graphs have not been updated at all. The captions and the fonts in general are too small, the FTIR graphs have the Bruker logo everywhere. The raw data should be replotted using origin, excel or another similar software.
Response. The figures have been improved as per direction of reviewer and highlighted in Turquoise.
- There is still no discussion about the UV-vis results for the nanocomposites. What is the point of including these graphs if nothing is said about them?
Response. The modifications have been addressed as per instruction of reviewer and highlighted in Dark Yellow.
Reviewer 3 Report
I am satisfied with the revision.
Author Response
Thank you very much for accepting our work.
Round 3
Reviewer 2 Report
The updated manuscript is better, although the English could still be improved.
The paper can be accepted after reviewing the following points:
- The TEM equipment description and experimental conditions are missing from the Materials and Methods section
- There is no point in having two TEM images in Figure 4, since both images are almost identical. They do not represent the view of the nanoparticles at different magnifications, as both images have the same magnification. Either replace one of them for a picture at a different magnification, or simply remove one of the pictures from the manuscript.
Author Response
Reviewer 2
The updated manuscript is better, although the English could still be improved.
Answer:
We are very thankful for this great suggestion for the improvement of the manuscript. we are sorry for the mistakes and grammatical errors. The English language of the manuscript has been improved and errors have been removed throughout of the manuscript. The changes in the revised manuscript have been marked in yellow color.
The paper can be accepted after reviewing the following points:
- The TEM equipment description and experimental conditions are missing from the Materials and Methods section
Answer:
We really appreciate the enlightening comment, which is of great help to improve the quality of this manuscript. According to the worthy reviewer’s suggestion, we have added the TEM equipment description and experimental conditions the revised manuscript. The changes in the revised manuscript have been marked in yellow color.
- There is no point in having two TEM images in Figure 4, since both images are almost identical. They do not represent the view of the nanoparticles at different magnifications, as both images have the same magnification. Either replace one of them for a picture at a different magnification, or simply remove one of the pictures from the manuscript.
Answer:
I appreciate the enlightening comment, which is of great help to improve the quality of this manuscript. We have removed one TEM image.
