Fabrication of Superhydrophobic and UV-Resistant Silk Fabrics with Laundering Durability and Chemical Stabilities
Round 1
Reviewer 1 Report
Silk was treated with SiH4 and HMDS and obtained some useful properties such as superhydrophobicity and UV-resistivity. Mechanical tests were carried out to investigate the durability of the fabric. The manuscript has the potential to be published in Coatings. But there are several concerns which should be addressed prior to further consideration.
1. The laundering test is an important part of this study as it is implied in the title. However, the laundering test is not described in the Experimental! The procedures and the conditions of the test should be described in detail (not in the main text).
Thank you for your helpful comment! We have described the laundering test in the Experimental. And the procedures and the conditions of the test have been described in detail.
2.5. Chemistry Stability Evaluation and Laundering Durability Evaluation
Put the silk fabrics in 25 ml hydrochloric acid solution and/or sodium hydroxide solution with different pH values in a glass bottle at 20 °C for 6 h. The accelerated laundering durability test of obtained silk fabrics were performed according to the AATCC 61-2009 method under conditions 2A. The test was performed using a standard color-fastness to washing laundering machine (model SW-12A, Changzhou Dahua Electronic Instrument Co., Ltd., China) equipped with 500 mL (75 mm × 125 mm) stainless-steel lever-lock canisters. The obtained silk fabrics were laundered in a rotating closed canister containing 150 mL aqueous solution of an AATCC standard WOB detergent (0.15%, w/w) and 50 stainless steel balls, with (2A condition) a water bath at 50 °C and 40 ± 2 rpm. One laundering cycle under the 2A condition is equal to 10 commercial or domestic launderings.
2. What was the wavelength range of the UV radiation?
Thank you for your helpful comment! The wavelength range of the UV radiation is 312 nm.
In order to study the ultraviolet resistance of the coating on the silk fiber, the uncoated and SiO2 coated silk fibers were exposed to the UV light (312 nm) with an intensity of 40 mW/cm2 for 1h. The distance between UV light and silk fabrics was fixed at 20 cm.
3. Contact angle measurements should be carried out after the UV-aging test to evaluate the stability of the wetting properties after UV exposure. This is a very crucial aspect which should be addressed.
Thank you for your helpful comment! We are very sorry for our negligence to show the contact angle of the obtained silk fabric after the UV-aging test to evaluate the stability of the wetting properties after UV exposure. In fact, we have measured the water contact angle of the obtained silk fabric after UV irradiation. And now, we have added this crucial data.
To evaluate the stability of the wetting properties after UV exposure, the contact angles of SiO2@silk fabric the before and after UV irradiation for 30 min were measured and showed in Fig. 4c and d. After UV irradiation, the wettability of the SiO2@silk fabric is almost unchanged. And it exhibit excellent surperhydrophobicity with WCAs of 150°, which indicate the wettability of the SiO2@silk fabric has a strong resistance to UV light.
4. The role of the HMDS posttreatment should be enlightened. What is the CA of the silk after treatment with SiH4 and before the HMDS step? Does HMDS affect the surface structure?- (probably not)
Thank you for your helpful comment! We have measured the CA of the silk after treatment with SiH4 and before the HMDS step and it can be completely wetted by water because of the SiO2 coating prepared by PECVD having plenty of hydroxyl groups. HMDS does not affect the surface structure of silk fabric, but changes its surface groups. It makes the surface of silk fabric obtain low surface energy, so it has superhydrophobic property.
5. Figure 2. (a) The caption in Figure 2 is unclear. The caption should describe clearly which sample is shown in any given image and what it is observed. From the text one can read that 2c and 2d correspond to the untreated silk and 2a and 2b to the treated. (?). Mapping images correspond to what and show what? (b) In the figure it is designated that Rq measurements are provided. In the text the same numbers are described as Ra measurements. (c) Standard deviations of the angle and the roughness measurements should be provided. I believe that for the j-m samples angle variations will be within the differences which are discussed in the text as actual results.
Thank you for your careful comment! We have revised it according to your comment in the manuscript. And we have provided the standard deviations of the angle and the roughness measurements.
Figures 2(a-d) show the FESEM images of SF and SiO2@silk fabric. It can be observed from FESEM images that the surface of the bare silk fabric is very smooth (Figure 2a,b). In contrast, numerous compact cracks and a small number of particle clusters could be found on the surface of SiO2@silk fabric (Figure 2c,d), which may be attributed to the aggregation of adjacent SiO2 nanoparticles. The lack of cracks suggests that the SFs were completely covered by SiO2 layer. Analysis by energy dispersive X-ray (EDX) mapping confirmed that the presence of continuous, uniform, and dense SiO2 coatings on the surface of the SiO2@silk fabric (Figure 2e-h). AFM images verified that the surface roughness of the silk fabrics significantly increased after PECVD (Figure 2j-m). As shown in Figure 2j-m, the arithmetic average roughness (Ra) measured was 118, 158, 125 and 121 nm for the SiO2-coated silk fabrics subjected to 2.5, 5, 7.5 and 10 min PECVD deposition, respectively. In contrast, the bare silk fabric exhibited Ra of just 74 nm (Figure 2i), which indicated that the SiO2 coating thus prepared obtains a certain surface roughness. After the deposition of SiO2 coating, the surface roughness of silk fabric will increase. However, when the amount of SiO2 is increased, the surface roughness of silk fabric will be reduced, which may be due to the further filling of some grooves (weaving) on the surface of silk fabric.
6. Standard deviations in the mechanical tests (and the other tests e.g. plots of Figure 5) are missing.
Thank you for your helpful comment! We have calculated the "standard deviation" for all the experimental tests and displayed in Table 1.
7. It would be useful to provide some sliding angles as these are equally important to characterise the wetting properties of a surface.
Thank you for your important comment! We have provided the sliding angles to characterise the wetting properties of the SiO2@silk fabrics.
8. Reference list should be enriched with other studies on superhydrophobic silk, some of which were published in COATINGS:
Superhydrophobic, Superoleophobic and Antimicrobial Coatings for the Protection of Silk Textiles, Coatings 2018, vol 8, 101.
Fabrication of multifunctional silk fabrics via one step in-situ synthesis of ZnO. Mater Lett. 2019; 237:149–151.
Thank you for your careful comment! We have added several references published in COATINGS.
Aslanidou D.; Karapanagiotis I. Superhydrophobic, superoleophobic and antimicrobial coatings for the protection of silk textiles. Coatings, 2018, 8, 101.
Huang J.J.; Yang Y.Y.; Yang L.; Bu Y.M.; Xia T.; Gu S.J.; Yang H.J.; Ye D.Z.; Xu W.L. Fabrication of multifunctional silk fabrics via one step in-situ synthesis of ZnO. Mater. Lett. 2019, 237, 149-151.
Reviewer 2 Report
This short paper deals with the manufacturing and the characterization of a superhydrophobic treatment based on a SiO2 coating, deposited on the surface of silk fabric (SF) using Plasma Enhanced Chemical Vapor Deposition (PECVD) technique. To this Reviewer, the paper is quite innovative and interesting and compliant with the Journal Coatings topics. The English language is fairly good, apart from some minor mistakes and typos.
I recommend publication, however, some major concerns about experimental methodology and completeness of results discussion should be addressed by the Authors to make the work to meet the rigorous scientific standards of the Journal. For the Authors convenience, in the following lines I try to justify my criticism.
1. From the editorial standpoint, it is advisable for the Authors to provide vector graphics (namely in .pdf or .eps format) to avoid grainy images, at least for charts. Besides, I personally would remove the dotted light-blue frames from the pictures.
Thank you for your important comment! We have removed the dotted light-blue frames from the pictures, and we have updated all the pictures.
2. Line 49: “PECVD is an effective conformal coating technology developed in recent years” – It is debatable to regard PECVD as a technology developed in “recent years”, contrarily, it is well-established, since the first papers I could find in the literature date back to the early Eighties (around 35-40 years ago). See, e.g., the paper by: Pai, P. G., Chao, S. S., Takagi, Y., & Lucovsky, G. (1986). Infrared spectroscopic study of SiO x films produced by plasma enhanced chemical vapor deposition. Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, 4(3), 689-694. The Authors should provide some further details about PECVD, referring to the available literature in the field.
Thank you for your careful comment! We are very sorry for our negligence of this mistake and we have deleted the “recent years”. Meanwhile, we have further provided some details about PECVD.
Plasma enhanced chemical vapor deposition (PECVD) is a technology that uses glow discharge to ionize thin gas in high frequency electric field to produce plasma. These ions are accelerated in the electric field to obtain energy, which can realize the growth of thin film at low temperature.[13]
Pai P.G.; Chao S.S.; Takagi Y. Infrared spectroscopic study of SiOx films produced by plasma enhanced chemical vapor deposition. J. Vac. Sci. Technol. A 1986, 4, 689-694.
3. In the introduction, this Reviewer cannot detect a literature overview regarding SiO2 in industrial applications. Silica is used as a coating agent in several contexts, due to its high versatility of usage and properties. The Authors should enlarge the introductory section by including a synthetic but exhaustive part devoted to silica, since they often mention its properties. Moreover, silica hydrophilicity/hydrophobicity strongly depends on manufacturing process. Moving from clothing to other fields, like structural engineering, biology or surface science, silica is adopted to enhance the surface reactivity with respect to water. For this reason, it is important that the Authors reserve a paragraph with appropriate length and references concerning an essential review about silica coatings and possibly the more common coating procedures. (I report some relevant papers, that the Authors should consider in the development of the topic, but of course it is not exhaustive). García, N., Benito, E., Guzmán, J., & Tiemblo, P. (2007). Use of p-toluenesulfonic acid for the controlled grafting of alkoxysilanes onto silanol containing surfaces: preparation of tunable hydrophilic, hydrophobic, and super-hydrophobic silica. Journal of the American Chemical Society, 129(16), 5052-5060. Signorini, C., Nobili, A., & Siligardi, C. (2019). Sustainable mineral coating of alkali-resistant glass fibres in textile-reinforced mortar composites for structural purposes. Journal of Composite Materials, 53(28-30), 4203-4213. […]
Thank you for your helpful comment! We have revised and added an essential advantages of silica coating.
SiO2 is the most favored inorganic materials and has been widely application because of its excellent chemical stability, mechanical strength and high transparency.[14]
Signorini C.; Nobili A.; Siligardi C. Sustainable mineral coating of alkali-resistant glass fibres in textile-reinforced mortar composites for structural purposes. J. Compos. Mater. 2019, 53, 4203-4213.
4. Line 67 – “SiO2 nano-films with a large amount of active hydroxyl groups were prepared on the surface of silk fabrics”. Is hydrophobicity conveyed only by the subsequent HMDS modification? On the basis of what declared by the Authors, silica coating appears highly hydrophilic. Please clarify.
Thank you for your careful comment! We have measured the CA of the silk after treatment with SiH4 and before the HMDS step and it can be completely wetted by water because of the SiO2 coating prepared by PECVD having plenty of hydroxyl groups. HMDS is used to changes surface groups of silk fabrics. It makes the surface of silk fabric obtain low surface energy, so it has superhydrophobic property. Therefore, HMDS is not the only modifier that can be used to modify the surface of silk fabric to obtain superhydrophobic properties.
5. Section 2.3. Characterization: K/S measures are not mentioned.
Thank you for your careful comment! We have added the K/S measures in the Characterization.
2.4. Characterization
Field emission scanning electron microscope (FE-SEM, JEOL JEM 6510LV) was used to acquire the surface morphology of the silk fabrics, with an operating voltage of 5 kV. The elemental composition of samples was analyzed using an X-ray energy dispersive spectroscopy (EDS) detector (QX200, Bruker, Germany) attached to the FE-SEM. The static water contact angles of the superhydrophobic surfaces through the above procedures were measured via the sessile drop technique using a KRUSS DSA100 (Shanghai Xuan Yi Chong Industrial Equipment Co. Ltd., Shanghai, China) contact angle system, with DI water drops of approximately 5 μL applied to five different spots for each coating. Atomic force microscopy (AFM) images were collected using a Park Systems XE-100 (Suwon, Korea) operating in noncontact mode. The color parameters (K/S values, L*, a*, b*) of all the silk fabrics before and after UV exposing were measured on an X-Rite color i7 computer color matching system with a CIE 10° and D65 illumination.
6. Section 2.3. Characterization: Tensile test specimens’ configuration, shape and cross-sectional area are mentioned nowhere, as well as information and images about testing machine, load cell, test set-up, strain rate etc. All these specifications are mandatory.
Thank you for your careful comment! We have added mechanical property of the all the silk fabrics measures in the Characterization.
According to the Chinese standard GB/T14337-2008, the mechanical property of the all the silk fabrics was measured on an electronic single-fiber tensile strength tester (LLY-06E, Laizhou Electronic Instrument Co., Ltd.). Two ends of the monofilament were fixed by pneumatic clamps with a gauge length of 20 mm. All sample tests were performed at 20 °C and a relative humidity of 63% with a crosshead speed of 10 cm/min. The measurement for each sample were repeated at least 20 times and the average value were calculated.
7. Line 157-158: “The values of L*, a* and b* were measured using an X-Rite color 158 i7 computer color matching system.” should be considered in Section 2.3.
Thank you for your careful comment! We have added the K/S measures in the Characterization.
Field emission scanning electron microscope (FE-SEM, JEOL JEM 6510LV) was used to acquire the surface morphology of the silk fabrics, with an operating voltage of 5 kV. The elemental composition of samples was analyzed using an X-ray energy dispersive spectroscopy (EDS) detector (QX200, Bruker, Germany) attached to the FE-SEM. The static water contact angles of the superhydrophobic surfaces through the above procedures were measured via the sessile drop technique using a KRUSS DSA100 (Shanghai Xuan Yi Chong Industrial Equipment Co. Ltd., Shanghai, China) contact angle system, with DI water drops of approximately 5 μL applied to five different spots for each coating. Atomic force microscopy (AFM) images were collected using a Park Systems XE-100 (Suwon, Korea) operating in noncontact mode. The color parameters (K/S values, L*, a*, b*) of all the silk fabrics before and after UV exposing were measured on an X-Rite color i7 computer color matching system with a CIE 10° and D65 illumination.
8. Lines 173 – 174: “the chemical durability of finished silk fabric (SF-2.5min) by soaking in different pH solution for 6 h” should again be considered in Section 2.3, in which no specifications about chemical and laundering tests are provided.
Thank you for your careful comment! We have added chemical and laundering tests in the Characterization.
9. Since several characterizations are carried out by the Authors, the Results section should be divided into sub-sections, to promote the readability of the paper.
Thank you for your important comment! We have divided the Results section into sub-sections.
3.1 Surface morphology and composition analysis
3.2 Surface wettability analysis
3.3 UV resistance analysis
3.4 The mechanical properties analysis
3.5 Chemistry Stability and Laundering Durability analysis
10. Lines 91 – 94 and Figure 1(a-b) should belong to Materials and Methods section and must be enlarged to better explain the process of silica deposition, possibly referring to the relevant literature previously disclosed. Figure 1 needs to be better explained, disclosing the objects inside the image (e.g. blue and yellow circles, black connectors etc…)
Thank you for your important comment! We have further explained the process of silica deposition in Materials and Methods section.
As can be seen from Figure 1a, the PECVD process for SiO2 deposition with SH4 and N2O can be separated into four step reactions. When SiH4 and N2O are used to prepare SiO2 thin films by plasma enhanced chemical deposition, the initial reactant is (SiH3) 2O, which is adsorbed on the substrate surface and reacts with oxygen atoms to form silicon dioxide with a stoichiometric ratio. Firstly, N2O is decomposed in the plasma to produce oxygen atom or oxygen radical, and the activated oxygen radical reacts with silane to form (SiH3) 2O, or participates in the formation of oxide on the surface. Details are described as follows:
11. Lines 131 – 133 “The color parameters (K/S values, L*, a*, b*) of the silk fabrics before and after UV exposing were measured on an X-Rite color i7 computer color matching system with a CIE 10° and D65 illumination. K/S represents the apparent color value of the sample.” is not appropriate in Section 3 (see previous part).
Thank you for your important comment! We have deleted “The color parameters (K/S values, L*, a*, b*) of the silk fabrics before and after UV exposing were measured on an X-Rite color i7 computer color matching system with a CIE 10° and D65 illumination. K/S represents the apparent color value of the sample.” in the Section 3 and added them in the Section 2.
2.5 UV resistance evaluation
The UV protection factor (UPF) values was calculated by the following equation[17,18]: where Eλ is the solar spectral irradiance(Wm–2·nm–1), Sλ is the relative erythema spectral effectiveness, Tλ is the averaged spectral transmittance of the fabric, and Δλ is the wavelength interval. The color parameters (K/S values, L*, a*, b*) of the silk fabrics before and after UV exposing were measured on an X-Rite color i7 computer color matching system with a CIE 10° and D65 illumination. K/S represents the apparent color value of the sample.
12. Figure 2 – Please disaggregate FE-SEM, EDX and AFM images, otherwise the result is a bit confused. Three different images are preferable for the three analyses, supplying clearer and complete captions to facilitate reading, for instance by defining in a clear way what specimens are observed in each image.
Thank you for your important comment! We have divided the Results section into sub-sections. FE-SEM and AFM images are used to observe the surface morphology of silk fabrics, EDS is used to determine the existence of Si elements on the surface of silk fabrics, so we put SEM, AFM and EDS images together as the surface morphology and components of samples for analysis. Meanwhile, we have separated the contact angles from Figure 2 for a separate wettability analysis.
13. Figure 2(a-d) – please embed some labels within the images to help the reader to identify what briefly described in Lines 102 – 104 “numerous compact cracks and a small number of particle clusters could be found on the surface of SiO2@silk fabric (Figure 2a,b), which may be attributed to the aggregation of adjacent SiO2 nanoparticles”. Where the Authors observe such particle clusters and cracks in the images? Please specify. Statements in Line 102 and 104 appear contradictory. Does the smooth surface (without cracks) belong to bare or coated fibres? In general, discussion in lines 100 – 104 and Figure 2(a-d) is confused. A rearrangement of concepts and terminology is required.
Thank you for your important comment! We can observe such particle clusters and cracks from the high magnification images of FESEM (Fig. 2 b and d). In addition, we adjusted the position of the FESEM images. Figure 2 a-b show FESEM images of the bare silk, and Figure 2 c-d show FESEM images of the SiO2@silk fabric.
It can be observed from FESEM images that the surface of the bare silk fabric is very smooth (Figure 2a,b). In contrast, numerous compact cracks and a small number of particle clusters could be found on the surface of SF-5SiO2 (Figure 2c,d).
14. Lines 107 – 114: It could be interesting to plot a chart correlating Ra and/or contact angle vs time of PECVD deposition to facilitate the discussion of the results, which appears confused. In particular, “After the deposition of SiO2 coating, the surface roughness of silk fabric will increase. However, when the amount of SiO2 is increased, the surface roughness of silk fabric will be reduced, which may be due to the further filling of some grooves (weaving) on the surface of silk fabric.” These sentences are contradictory. Maybe the Authors mean that Ra is not a monotonic function of the PECVD exposure time, reaching a maximum at around 5 min then it decreases, since silica further fills of some grooves (weaving) on the surface of silk fabric. Am I correct? Please reformulate the comment.
Thank you for your important comment! I'm sorry for the confusion caused by our unclear statement. Your analysis is very correct. And we have revised it.
However, Ra is not a monotonic function of the PECVD exposure time, reaching a maximum at around 5 min then it decreases, since silica further fills of some grooves (weaving) on the surface of silk fabric.
15. A rigorous experimental scheme (possibly within a synthetic Table in section 2.3 “Characterization”) with clear and consistent declaration of samples acronyms (For instance BF (bare fabric), SF-2.5, SF-5.0 etc. to identify coated silk fibres and time of PECVD) should be provided. Pre-defined labels/acronyms must be used throughout the manuscript every time that relevant samples are mentioned during the discussion. This reviewer has found difficult to follow the stream of the discussion (what does it mean “finished silk fabric” in lines 138, 139? Nowhere is defined: do the Authors mean “SiO2 coated?”)
Thank you for your important comment! we have provided clear and consistent declaration of samples acronyms, and revised them in the manuscript.
Finally, the corresponding sample with various thickness SiO2 coating and modified by HMDS were obtained and denoted as SF-nSiO2. Here, n indicated the time of SiO2 deposition by PEVCD, respectively.
16. Figure 3 is confused. Please consider separating charts for UV resistance to mechanical characterization and please improve captions, which should be adequate to understand the figure as a standalone item. What is the different meaning of Fig.3c and Fig.3d? It is not clear to me.
Thank you for your important comment! We have revised the item.
17. K/S values deserve a deeper discussion (Lines 138 – 140) and results must be contextualised and possibly analysed by means of relevant findings in the literature.
Thank you for your important comment!
In addition, we measured the K/S values before and after UV irradiation for bare silk and SF-nSiO2, as shown in Figures 3(c,d). Compared with bare silk, the K/S values of SF-nSiO2 slowly increased and lower than that of bare silk. It indicates that SF-nSiO2 has UV resistance. SF-nSiO2 is not easy to fade after UV irradiation.
It is well agreed with the K/S analysis above.
18. No specifications about the calculation of fracture work are provided. Is it computed as the area under the stress-strain curves? In that case, mean curves should be plotted alongside the mean values.
Thank you for your important comment! We use the electronic single fiber strength tester to measure the silk fibers, and the fracture works are directly read from the instrument display screen. The equipment microcomputer automatically fits the data according to the the Chinese standard GB/T14337-2008.
19. Figure 3(a, e and f): No standard deviation bands are provided on the bar-charts. They are mandatory.
Thank you for your important comment! We have added the standard deviation bands on the Table 2.
20. Figure 3(e): The Authors mention “tensile stress” and use a force measure unit (cN). It is preferable to write “tensile load” or, even better, provide results in terms of stress, in Pascal unit, which are independent of the specimen’s configuration.
Thank you for your important comment! We measured the “tensile stress” by the electronic single fiber strength tester according to the the Chinese standard GB/T14337-2008. The “tensile stress” directly read from the liquid crystal display control system with a measure unit (cN).
21. Line 145-146: “It is clearly seen that the values of tensile stress and work fracture of SiO2-coated silk fabrics are higher than that of bare silk”. It seems not so clear as far as fracture energy is considered, at least for samples not exposed to UV. Besides, I notice that for those samples, the tensile load increases but energy decreases. Does it mean that coating induces a pronounced reduction in ductility? This (negative) aspect, if true, is worth to be considered and discussed and possibly compared in the light of the existing literature. Lines 141-148: In general, discussion of the results is quite basic and no correlation with existing literature and with the other measurements is provided. For example, in which way silica affects mechanical properties of the fibre? Why SiO2 induces an enhancement in terms of fracture energy in case of UV-aged silk fibres?
Thank you for your important comment! It is clearly seen from test data that the values of tensile stress and work fracture of SiO2-coated silk fabrics are higher than that of bare silk. However, the reason why silica can enhances the mechanical properties of parametric fibers may be related to many aspects, such as the mechanical strength and band gap of silica. Of course, the influence of band gap of the SiO2 and other factors is also of high research value, which is also the content we are currently studying. Thank you!
22. All the acronyms should be declared. Please check
Thank you for your important comment! we have provided clear and consistent declaration of samples acronyms, and revised them in the manuscript.
Finally, the corresponding sample with various thickness SiO2 coating and modified by HMDS were obtained and denoted as SF-nSiO2. Here, n indicated the time of SiO2 deposition by PEVCD, respectively.
23. Line 35: do the Authors want to produce textiles with “poor UV resistance”? Maybe a typo?
Thank you for your important comment! We have revised it.
Therefore, producing high-value-added textiles, such as hydrophobic silk fabric and excellent UV resistance, is of great significance.
24. Line 76: UV Radiation Treatment section is 2.2.1 or 2.3? in the latter case, please correct the following section numbering accordingly.
Thank you for your important comment! We have revised it.
2.3. UV Radiation Treatment
25. Line 79: Are there any guidelines to assess the UV resistance of textiles or your tests have a mere comparative purpose? The Authors should declare it.
Thank you for your important comment! The UPF value is used to assess the UV resistance of textiles.
26. Lines 188 – 189: “Meanwhile, both the laundering durability and chemical stability of the SiO2@silk fabric were” Is redundant, since the same concept is expressed the line above.
Thank you for your important comment! We have revised it.
27. Line 18: remove “a”, “[…] fabric was confirmed with high UV protection factor (UPF) values”
Thank you for your important comment! We have revised it.
The excellent UV resistance of SiO2@silk fabric was confirmed with high UV protection factor (UPF) values and a low transmittance in the wavelength range of 280-400 nm.
28. Line 136: It indicates […]
Thank you for your important comment! We have revised it.
29. Line 141: “the mechanical properties of materials is important for evaluating […]”
Thank you for your important comment! We have revised it.
In addition, the mechanical properties of materials is important for evaluating its practical applications.
30. Line 159: “As Fig. 4 shows, […]”
Thank you for your important comment! We have revised it.
As Fig. 4a,b shows,
2.5. Chemistry Stability Evaluation and Laundering Durability Evaluation
Put the silk fabrics in 25 ml hydrochloric acid solution and/or sodium hydroxide solution with different pH values in a glass bottle at 20 °C for 6 h. The accelerated laundering durability test of obtained silk fabrics were performed according to the AATCC 61-2009 method under conditions 2A. The test was performed using a standard color-fastness to washing laundering machine (model SW-12A, Changzhou Dahua Electronic Instrument Co., Ltd., China) equipped with 500 mL (75 mm × 125 mm) stainless-steel lever-lock canisters. The obtained silk fabrics were laundered in a rotating closed canister containing 150 mL aqueous solution of an AATCC standard WOB detergent (0.15%, w/w) and 50 stainless steel balls, with (2A condition) a water bath at 50 °C and 40 ± 2 rpm. One laundering cycle under the 2A condition is equal to 10 commercial or domestic launderings.
Reviewer 3 Report
1. Title of article presents the topic in the presented paper.Abstract of article is well written and gets readers attention. Word HMDS should be also in the Keywords. Introduction is well written. Background was presented with suitable literature/references.
Thank you for your helpful comment! We have added the HMDS in the Keywords.
2. line 42 writing mistake - et al [10]. have successfully... --> et al. [10] have successfully...
Thank you for your careful comment! We are very sorry for our negligence of this mistake. We have checked and revised, thank you!
3. In topic Materials readers from all over the word will not be interested in reading, who was a supplier of the material. Researchers are more interested in purity/quantity/concentration... of material. Well written --> had a resistivity of 10-16 MΩ·cm at 25°C. For this reason it is suggested to merge 2.1 and 2.2 in one topic.
Thank you for your careful comment! But, we are sorry that we can’t merge 2.1 and 2.2. 2.1 show the materials in this manuscript, but the 2.2 describes the preparation process of materials. The high-purity water is made in our laboratory, and it's been described in this way in many published papers.
4. lines 67-75 Readers do not get the insight on the scale of plasma reactor (big, small --> dimensions, picture...), frequency of plasma (RF, MF...), sample dimensions... what was the number of samples? Inlet of gas/flow rate is dependent on the vacuum system/pumps (rpm), where was the mixture of gas made? tolerances of measuring systems/instruments are not presented/known. Experiment can not be repeated, because there are not enough information. If somebody decides to repeat the experiment, he will get different result, because he can not use the same procedure.
Thank you for your helpful comment! The mixture of gas is purchased from Wuhan Minghui Co., Ltd. Each device has different built-in parameters. It is worth noting that the key parameters that really affect the properties of the materials prepared by PECVD should be reaction temperature, gas flow rate, RF power and deposition time. Before any scientific experiment, we must adjust the parameters of the equipment. Of course, we have provided some important parameters.
SiH4 (Helium mixture, 10% of silane volume), N2 (99.999% purity) and N2O were purchased from Wuhan Minghui Co., Ltd.
The reaction temperature was setting at 150 °C, the deposition pressure was setting at 90 Pa, the RF power was setting 50 W and the deposition time is 5 minutes. SiH4 (Helium mixture, 10% of silane volume) and N2O (99.999% purity) were used as reaction gas sources. The gas flow rate of SiH4 was 65 sccm (sccm: standard milliliter/minute) and N2O was 450 sccm, respectively. High purity N2 (99.999%) is scavenging gas, and its flow rate is controlled at no less than 13.4 sccm.
5. line 68 The reaction temperature was 150 °C --> How was the temperature of reaction measured
Thank you for your helpful comment! PECVD equipment has built-in temperature sensor, which can be directly read from the liquid crystal display control system after setting the corresponding temperature.
6. line 76-79 Well written, but can be improved with experiment description
Thank you for your helpful comment! We have revised the experiment description.
7. line 95 contact angle (CA), and than it can be used as CA
Thank you for your helpful comment! We have revised it.
8. line 108 Ra is not equal to Rq, please update the drawing with Ra (Figure 2i-m)
Thank you for your helpful comment! We have updated the drawing with Ra (Figure 2i-m).
9. line 149 of Figure 3,4,5, bigger font should be used. Writing is not clearly visible.
Thank you for your helpful comment! We have updated the Figure 3,4,5.
10. line 163 from 93 to 56 while the YI increased from 8 to 68, exhibiting yellowing --> can get even better results. For this reason it is necessary to describe the experiment in detail (rpm of pumps, position of cathodes, inlet of gas mixture, P[kW], p[mbar], RF or MF plasma, thickness of SiO2 layer) --> the problem of YI is well known in automotive light industry of high vacuum metalization process
Thank you for your helpful comment! Each device has different built-in parameters. It is worth noting that the key parameters that really affect the properties of the materials prepared by PECVD should be reaction temperature, gas flow rate, RF power and deposition time. Before any scientific experiment, we must adjust the parameters of the equipment. Of course, we have provided some important parameters.
SiH4 (Helium mixture, 10% of silane volume), N2 (99.999% purity) and N2O were purchased from Wuhan Minghui Co., Ltd.
The reaction temperature was setting at 150 °C, the deposition pressure was setting at 90 Pa, the RF power was setting 50 W and the deposition time is 5 minutes. SiH4 (Helium mixture, 10% of silane volume) and N2O (99.999% purity) were used as reaction gas sources. The gas flow rate of SiH4 was 65 sccm (sccm: standard milliliter/minute) and N2O was 450 sccm, respectively. High purity N2 (99.999%) is scavenging gas, and its flow rate is controlled at no less than 13.4 sccm.
11. Conclusion - Well written, but can be improved
Thank you for your helpful comment! We have revised the experiment description.
In this study, a robust superhydrophobic and UV resistant silk fabrics was successfully prepared. Characterization of the surface morphology, topography and structure revealed that PECVD SiO2 coatings were formed successfully on the surface of silk fabrics. Compared with bare silk, the surfaces of the SiO2@silk fabric exhibit higher surface roughnesses and excellent superhydrophobic activity with a contact angle of ~152°. The excellent UV resistance of SiO2@silk fabric was confirmed with a high UV protection factor (UPF) values and a low transmittance in the wavelength range of 280-400 nm. In addition, both the laundering durability and chemical stability of the SiO2@silk fabric was improved. Overall, the PECVD method described here is a promising strategy to achieve high surface roughness. Furthermore, this approach might improve to advance large-scale-area application in various fields to achieve UV protection, and superhydrophobic properties.
Round 2
Reviewer 1
The authors did a great job as they have carefully revised their manuscript and addressed all of my concerns. The revised manuscript can be published in Coatings.
The format of Table 1 should be considered by the authors or the publisher as the first column is somewhat distorted (e.g. sil-k).
Thank you for your helpful and positive comments on our work! We have added the standard deviation bands directly on the bar-chart, to provide an immediate view of the extremely high repeatability of the tests.
Reviewer 2
The Authors' effort to address all my comments and remarks is really valuable.
To my opinion, the paper is now suitable for publication in the Journal "Coatings".
The experimental section is now clear and exhaustive and results are presented in a more structured and rigorous way.
I heartily recommend to consider adding standard deviation bands directly on the bar-charts, to provide an immediate view of the extremely high repeatability of the tests the Authors have conducted.
Please, check table 1 on the manuscript, which lines seem misplaced.
Thank you for your helpful and positive comments on our work! We have added the standard deviation bands directly on the bar-chart, to provide an immediate view of the extremely high repeatability of the tests.
