Formation of Coatings Based on Titanium Dioxide Nanosolson Polyester Fibre Materials
Round 1
Reviewer 1 Report
In this manuscript, the study fabricated an Ultrathin TiO2 film was adhered firmly on the surface of polyester fibres with increased photochemical activity by doping TiO2 with iron and silver, which supported its potential properties to be applied in practical use. It is an interesting work that used of TiO2 nanoparticles doped with silver as the modifier achieved a considerable increase in the photodegradation of the dye adsorbed by the fabric. A lot of experiments have also been carried out to support its conclusions. Comments would suggest to the writing.
Figure 1 presents that SEM images and claimed the modified fabric retain its high-performance characteristics – softness and good drapability. Performance, measurement results and analysis of the treated fabric absented in the manuscript.
In the figure 2, the value of color difference (%) shown on the Y-axis didn’t give the calculation formula in detail.
The manuscript needs to explain why TiO2 doping can increase decomposition rate, and why the pre-activation effect on the photochemical properties is different among undoped and doped TiO2
The Purple line presents in Figures a & b, why it absents in Figure c?
The authors compared the difference among the three kind of samples (audoped, doped with iron and doped with silver) in Figure 4, and continued to analysis the reason in Figure 5 and Table 1. However, there are just two sample were discussed without undoped sample. Hence, in Figure 5 and Table 1, the study results of undoped sample should be also added in order to explain the difference in Fig 4 completely.
Comparison of coated polyester fabric before washing and after washing the study needs present SEMs with same magnification in Figure 7.
For the washability, authors are suggested to tell clearly about the laundering times.
“Since the structure of the coating based on TiO2 nanoparticles doped with silver was dense and ordered, the coating had good wash-resistance and excellent abrasion-resistance.” Supporting data and further explanation are absented.
Author Response
Question 1
Figure 1 presents that SEM images and claimed the modified fabric retain its high-performance characteristics – softness and good drapability. Performance, measurement results and analysis of the treated fabric absented in the manuscript.
Answer 1
We evaluated the softness and drape of the fabric by its stiffness (inflexibility). We additionally included in the manuscript a method for determining stiffness (lines 181-189), experimental data and their discussion (lines 221-224 and 232-234).
Question 2
In the figure 2, the value of color difference (%) shown on the Y-axis didn’t give the calculation formula in detail.
Answer 2
We did not calculate the values of the colour difference. We received them automatically through the use of a colour measuring complex equipped with the Colorist program (version 4.2.1994, 2000, authors Pobedinsky V.S., Telegin F.Yu., Danilin I.A.) (lines 166-169). The program performed calculations based on formulas recommended by the CIE International Committee.
Question 3
The manuscript needs to explain why TiO2 doping can increase decomposition rate, and why the pre-activation effect on the photochemical properties is different among undoped and doped TiO2
Answer 3
Doping of TiO2 with metals significantly increases the redox potential of the formed radicals and increases the quantum efficiency by reducing the degree of recombination of electrons and holes. This leads to an increase in the activity of the photocatalyst. This information added to the manuscript (lines 98-100).
in comparison with undoped TiO2, activation has less effect on the rate of the dye photochemical decomposition by a polyester fabric coated with TiO2 nanoparticles doped with metals. This is probably due to a change in the adhesive properties of TiO2 as a result of doping with metals. This information added to the manuscript (lines 275-276)
Question 4
The Purple line presents in Figures a & b, why it absents in Figure c?
Answer 4
The question is not clear. In Figures 3 a, b & c there are black, red and green lines, in Figures 4 a, b & c and Figures 6 a, b & c there are black and red lines. Purple lines are absent everywhere. Perhaps the presence of purple lines in a number of Figures is due to a technical malfunction of the monitor.
Question 5
The authors compared the difference among the three kind of samples (audoped, doped with iron and doped with silver) in Figure 4, and continued to analysis the reason in Figure 5 and Table 1. However, there are just two sample were discussed without undoped sample. Hence, in Figure 5 and Table 1, the study results of undoped sample should be also added in order to explain the difference in Fig 4 completely.
Answer 5
We added the results of the study of the undoped sample to Figure 5 and to Table 2. We also made changes in the discussion of the results (lines 284-286, 303, 311).
Question 6
Comparison of coated polyester fabric before washing and after washing the study needs present SEMs with same magnification in Figure 7.
Answer 6
In Figures 7a and 7b we presented the results of SEM studies with the same magnification.
Question 7
For the washability, authors are suggested to tell clearly about the laundering times.
Answer 7
The washing duration was 60 minutes. Information added to the manuscript (line 173).
Question 8
“Since the structure of the coating based on TiO2 nanoparticles doped with silver was dense and ordered, the coating had good wash-resistance and excellent abrasion-resistance.” Supporting data and further explanation are absented.
Answer 8
We added some explanation (lines 389-391): “This indicates the durability of coatings based on TiO2 nanoparticles doped with silver and their high consumer characteristics.”
Reviewer 2 Report
The authors present the results of a study concerning the modification of polyester fabrics with doped and un-doped TiO2 in nano-sol form. They determine conditions at which the treated fabrics offer good photochemical activity and limited bacterial resistance, while maintaining desirable mechanical properties.
This is a detailed study, well-documented. I believe it should be published.
A couple of queries: The key to the success of the treatment process is the formation of a ultra-thin coating on the surface of the polyester fiber. Figure 7(a) seems to show this rather clearly. Figures 1b,1C, 2b, 2c, on the other hand do not seems to show "a nanostructure" or "order" - lines 210-211. In Figure 5, also, it is not clearly shown that the coating becomes denser when Ag is present (lines 282-283). Maybe these can be clarified.
All fabrics are multi-scale materials, with fibrils bundling together in tows, which are then woven. This is clear in Figure 1a, 2a. A comment to teh extent of surface modification of filaments located in the INSIDE of the tows (bundles) may be warranted.
Author Response
Question 1
A couple of queries: The key to the success of the treatment process is the formation of a ultra-thin coating on the surface of the polyester fiber. Figure 7(a) seems to show this rather clearly. Figures 1b,1C, 2b, 2c, on the other hand do not seems to show "a nanostructure" or "order" - lines 210-211. In Figure 5, also, it is not clearly shown that the coating becomes denser when Ag is present (lines 282-283). Maybe these can be clarified.
Answer 1
We set the task of forming an ordered and firmly fixed TiO2-based coating on each fiber without depositing a modifier in the inter-fiber space. Figures 2a, 2b prove the absence of TiO2 in the inter-fiber space. Figure 2b shows that the coating is smooth; the dimensions of its structural elements are several angstroms (Fig. 2c). The structure and properties of a TiO2-based coating, depending on its thickness, were described in detail in our earlier article (Prorokova N.P.; Kumeeva T.Yu.; Agafonov A.V.; Ivanov V.K. Modification of polyester fabrics with nanosized titanium dioxide to impart photoactivity. Inorg. Mater. Appl. Res. 2017, 8, 696–703. DOI: 10.1134/S2075113317050264). We agree that only on the basis of Figure 5 is it difficult to estimate the density of the coating. Therefore, we specially conducted an additional study of the density of coatings by force spectroscopy. The results we presented in Table 2.
Question 2
All fabrics are multi-scale materials, with fibrils bundling together in tows, which are then woven. This is clear in Figure 1a, 2a. A comment to teh extent of surface modification of filaments located in the INSIDE of the tows (bundles) may be warranted.
Answer 2
To the important question about the degree of surface modification of filaments located in the inner regions of fabrics, we answered at the first stage of the study. For this, we compared the coatings of filaments pulled from the inner regions of fabrics and located on the surface. The structure and properties of such coatings turned out to be the same. This information is of great importance for our further researches, but we decided not to provide it in the manuscript. The structure and properties of the filament coatings of the inner regions of the fabric are not important when giving the fabric photocatalytical properties. Only the illuminated surface of the fabric should be able to discolor pollution.
Round 2
Reviewer 1 Report
For the question 4, the purple line (straight not curve) presents in the Figure 4a and 4b, but absents in the Figure 4c. This also happen in the Figure 6. For the question 7, it’s how many times of laundering procedure, not how much time of it.Author Response
Question
For the question 4, the purple line (straight not curve) presents in the Figure 4a and 4b, but absents in the Figure 4c. This also happen in the Figure 6.
Answer
We found the reason of the appearance of purple straight lines in figures 4a, 4b, 6a, 6b. This was a technical error. We replaced these figures.
Question
For the question 7, it’s how many times of laundering procedure, not how much time of it.
Answer
The washing procedure was carried out 3 times. A corresponding addition was included in the manuscript (lines 171-172).
