Studies of Polylactic Acid and Metal Oxide Nanoparticles-Based Composites for Multifunctional Textile Prints

Round 1

Reviewer 1 Report

The manuscript is original and contains a significant result in various specialized applications. However, this manuscript cannot be accepted for publication in the present form due to the following issues. Therefore, I recommend for a major revision.

1. The units should be reported in all the tables (the two tables (dye, urea...) in page 4, table 1, 2 (unit of K/S), 3 (wet, dry...), 4 (wool, acrylic), 5 and 6.

2. In page 4, lines 137- 139 "The fabrics were then subjected to padding and squeezed to 80% pick-up followed by drying at 60oC. The padded samples treated with ZnO and TiO2 nanoparticles were cured at 140oC for 10 minutes, while the fabrics treated with MgO nanoparticles were cured at 120oC for 3 minutes. Why the temperature and the time are different for the ZnO, TiO2 and MgO nanoparticules? How we can study three effects at the same time?

3. Why theses chemical elements (Al (Fig 5), Si (Fig 5), Na (Fig 6 and 9), Ca (Fig 9), K (Fig 9), Cl (Fig 9),  present in EDX diagram?

4. Why the chemical elements S wasn't detected by EDX in Fig 8, however, it was detected in untreated acrylic fabric in Fig 7.

5. Page 13, line 285 to 290 "Upon increasing ....with TiO2 nanaparticules", and page 14, line 310 to 318 "When increasing ....acrylic fibers." authors should discuss the origin of the evolution of K/S in pre-treatment and in post-treatment of wool fabrics and acrylic fabrics.

6. Page 13, line 293 to 298 "The increased ....strength" here the authors explicate that the increased color could attributed by the Ti4+ ions. In this case, we can ask that does the increase in concentration of TiO2 induced the increase of Ti4+?

7. Page 14, line 301 to 304 "In general ....ZnO" and line 318 to 321 "General ....ZnO" the authors should explicate why the pre-treatment approach displayed higher color strength compared to post-treatment process. If this effect was observed in literature, so it's necessary for reports the reference.

8. Page 14, the last line in table 2 (0.5) seems to be a portion of MgO nanoparticules.

Author Response

Reviewer # 1: The manuscript is original and contains a significant result in various specialized applications. However, this manuscript cannot be accepted for publication in the present form due to the following issues. Therefore, I recommend for a major revision.

1. The units should be reported in all the tables (the two tables (dye, urea...) in page 4, table 1, 2 (unit of K/S), 3 (wet, dry...), 4 (wool, acrylic), 5 and 6.

Authors’ response: Thank you for your valuable suggestion. Units were reported for Tables 1 and 2. There are no units for values in Tables 3-8 because the recorded values could be described as poor, medium or excellent depending on a certain scales previously reported in literature. For instance, the light fastness is assessed depending on international blue scale (1-8), while the washing fastness is evaluated depending on international grey scale (1-5), with scales 8 and 5, respectively, ranked the best, while 1 is the most inferior.

2. In page 4, lines 137- 139 "The fabrics were then subjected to padding and squeezed to 80% pick-up followed by drying at 60oC. The padded samples treated with ZnO and TiO2 nanoparticles were cured at 140oC for 10 minutes, while the fabrics treated with MgO nanoparticles were cured at 120oC for 3 minutes. Why the temperature and the time are different for the ZnO, TiO2 and MgO nanoparticules? How we can study three effects at the same time?

Authors’ response: Thank you for your valuable suggestion. Each metal oxide has an optimum curing conditions previously studied and reported in literature as cited in the current manuscript. Our new and major target in the current manuscript is to study the effects of those metal oxide nanoparticles on both natural wool and synthetic acrylic fabrics upon using novel polylactic acid-based printing paste toward multifunctional textile prints.

3. Why theses chemical elements (Al (Fig 5), Si (Fig 5), Na (Fig 6 and 9), Ca (Fig 9), K (Fig 9), Cl (Fig 9),  present in EDX diagram?

Authors’ response: Thank you for your valuable suggestion. The major elements were recorded at a high percentage. For example, carbon, sulfur, nitrogen and oxygen were found to be the major elements for wool fibers. However, other elements were monitored at a very low concentration, such Al, Si, Na, Ca, K and Cl. Those traces of elements can be attributed to the other components and salts used in the printing paste. For example, sodium element is due to the used Ludigol (the sodium salt of m-nitrobenzene sulfonic acid). Also, EDX method is an excellent detection approach for all elements with a certain little error (Ref.: K. Pantzas, G. Patriarche, D. Troadec, S. Gautier, T. Moudakir, S. Suresh, L. Largeau, O. Mauguin, P. L. Voss, and A. Ougazzaden. Nanotechnology 23, no. 45 (2012): 455707).

4. Why the chemical elements S wasn't detected by EDX in Fig 8, however, it was detected in untreated acrylic fabric in Fig 7.

Authors’ response: Thank you for your valuable suggestion. The major elements for acrylic fibers, including carbon, oxygen and nitrogen, were recorded at a high percentage. However, sulfur was monitored at a very low concentration because EDX is an elemental detection technique for all elements with a certain little error (Ref.: K. Pantzas, G. Patriarche, D. Troadec, S. Gautier, T. Moudakir, S. Suresh, L. Largeau, O. Mauguin, P. L. Voss, and A. Ougazzaden. Nanotechnology 23, no. 45 (2012): 455707).

5. Page 13, line 285 to 290 "Upon increasing ....with TiO2 nanaparticules", and page 14, line 310 to 318 "When increasing ....acrylic fibers." authors should discuss the origin of the evolution of K/S in pre-treatment and in post-treatment of wool fabrics and acrylic fabrics.

Authors’ response: Thank you for your valuable suggestion. Explanation was included and cited.

6. Page 13, line 293 to 298 "The increased ....strength" here the authors explicate that the increased color could attributed by the Ti4+ ions. In this case, we can ask that does the increase in concentration of TiO2 induced the increase of Ti4+?

Authors’ response: Thank you for your valuable suggestion. Explanation was included and cited.

7. Page 14, line 301 to 304 "In general ....ZnO" and line 318 to 321 "General ....ZnO" the authors should explicate why the pre-treatment approach displayed higher color strength compared to post-treatment process. If this effect was observed in literature, so it's necessary for reports the reference.

Authors’ response: Thank you for your valuable suggestion. Explanation was included and cited.

8. Page 14, the last line in table 2 (0.5) seems to be a portion of MgO nanoparticules.

Authors’ response: Thank you for your valuable suggestion. Table was fixed.

Author Response File: Author Response.docx

Reviewer 2 Report

A new approach to produce multifunctional printed technical textiles was proposed in this manuscript, the effect of before-treatment and post-treatment by three metal oxide nanoparticles were compared. However, this manuscript was not well organized, the discussions of experimental phenomena were also insufficient.

The pre- and post-treatment process of wool and acrylic fabrics by nanoparticals were not found in section 2.4, it should be added. For self-cleaning activity analysis, how did the authors get the Dye removal % value in table 7, it seems to be no explanation in section 3.6. And, the formula Photocatalytic degradation = (C₀ - C_t/C₀) in section 2.7, which was employed to self-cleaning activity ability, could authors explain why. C₀ – C_t or (C₀ – C_t)/C₀ should be better for the results. The scale of SEM images in figure 3-9 were chaotic. For example, scale of SEM images in figure 3 were 200, 50 μm respectively, while they were 50, 100 μm in figure 4, and 50, 500 μm in figure 8 and so on. It could be better to remain the scale between each figure the same. The section 3.1 (results) seems to be more about methods, with less results and duplication with the conclusions. In section 3.3, according to the authors inference, Ti⁺⁴ ions could lead to positive charges increasing which caused more ionic attraction to the acid anionic dyestuffs and increased the bonding process between dyestuff and fabric. Why with the increasing of metal oxide nanoparticles concentrations (Ti⁺⁴ ions), the color strength values didn’t increase. The content of Funding and Author Contributions should change the template content to the actual information of the authors. There is not much about the exhausion approach for the incorporation of metal oxide nanoparticles onto both natural and synthetic textile fibers in the article. The principle of this method can be briefly introduced. The sequence of Figures 3 to 9 looks a little confusing. The untreated groups used as controls are not shown in Tables 1 and 2. The conclusion section is too short.

Author Response

Reviewer # 2: A new approach to produce multifunctional printed technical textiles was proposed in this manuscript, the effect of before-treatment and post-treatment by three metal oxide nanoparticles were compared. However, this manuscript was not well organized, the discussions of experimental phenomena were also insufficient.

1. The pre- and post-treatment process of wool and acrylic fabrics by nanoparticals were not found in section 2.4, it should be added.

Authors’ response: Thank you for your valuable suggestion. Both pre- and post-treatment processes of wool and acrylic fabrics by nanoparticals were demonstrated in section 2.4.

2. For self-cleaning activity analysis, how did the authors get the Dye removal % value in table 7, it seems to be no explanation in section 3.6.

Authors’ response: Thank you for your valuable suggestion. The dye degradation/removal % value displayed in Table 7 was evaluated according to procedures explained in section “2.7. Analysis and measurements/Self-cleaning activity”.

3. And, the formula Photocatalytic degradation = (C₀ - C_t/C₀) in section 2.7, which was employed to self-cleaning activity ability, could authors explain why. C₀ – C_t or (C₀ – C_t)/C₀ should be better for the results.

Authors’ response: Thank you for your valuable suggestion. This approach/equation has been used in numerous publications to describe the photocatalytic degradation process, in which C₀ is the initial concentration of methylene blue, C_t is the concentration at different irradiation time periods, A₀ is the initial absorption and A_t is the variable absorption at different irradiation time periods. Thus, we used the absorbance value to estimate the concentration of methylene blue, and consequently to evaluate photocatalytic self-cleaning activity. Generally, the metal oxide nanoparticles employ a distinctive self-cleaning mechanism by combining an initial photocatalysis with a subsequent hydrophobic step. Upon exposure to ultraviolet light, metal oxide nanoparticles produce free electrons which interact with oxygen and water molecules in the air to generate free radicals. Those free radicals have the ability to degrade organic matter fouling on the fabric surface. Due to the hydrophobic effect generated by the metal oxide nanoparticles on the fabric surface, water can then wash the fabric surface from any surface debris.

4. The scale of SEM images in figure 3-9 were chaotic. For example, scale of SEM images in figure 3 were 200, 50 μm respectively, while they were 50, 100 μm in figure 4, and 50, 500 μm in figure 8 and so on. It could be better to remain the scale between each figure the same.

Authors’ response: Thank you for your valuable suggestion. Each metal oxide based nanoprticles has different size of nanoparticles and even the blank fabrics (wool and acrylic) were different in morphology than treated ones (coated with nanoparticles). Thus, we selected images with the best scale depending on treated/untreated(blank) fabric and size of nanoparticles.

5. The section 3.1 (results) seems to be more about methods, with less results and duplication with the conclusions.

Authors’ response: Thank you for your valuable suggestion. Section 3.1 is significant because it briefly described the combined procedures for the preparation of multifunctional fabrics. Conclusion was revised/rewritten.

6. In section 3.3, according to the authors inference, Ti⁺⁴ ions could lead to positive charges increasing which caused more ionic attraction to the acid anionic dyestuffs and increased the bonding process between dyestuff and fabric. Why with the increasing of metal oxide nanoparticles concentrations (Ti⁺⁴ ions), the color strength values didn’t increase.

Authors’ response: Thank you for your valuable suggestion. Explanation was included and cited.

7. The content of Funding and Author Contributions should change the template content to the actual information of the authors.

Authors’ response: Done

8. There is not much about the exhausion approach for the incorporation of metal oxide nanoparticles onto both natural and synthetic textile fibers in the article. The principle of this method can be briefly introduced.

Authors’ response: The principle of the exhaustion method was briefly introduced in introduction section.

9. The sequence of Figures 3 to 9 looks a little confusing.

Authors’ response: Thank you for your valuable suggestion. Figures 3-9 were ordered according to the type of fabric (blank or treated). Figures 3-9 are very significant in the current manuscript to describe the morphological properties of treated/untreated fabrics.

10. The untreated groups used as controls are not shown in Tables 1 and 2.

Authors’ response: Thank you for your valuable suggestion. The control fabrics are the printed fabrics but untreated with nanoparticles as described in manuscript and Tables 1, 2.

11. The conclusion section is too short.

Authors’ response: Thank you for your valuable suggestion. Conclusion was revised.

Thank you very much!

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

This version of the manuscript has been significantly improved. I recommend this manuscript for publication in Coatings.

Best regards.

Reviewer 2 Report

The authors have addressed most of questions raised by the reviewers.