Synthesis, Properties and Adsorption Kinetic Study of New Cross-Linked Composite Materials Based on Polyethylene Glycol Polyrotaxane and Polyisoprene/Semi-Rotaxane
Round 1
Reviewer 1 Report
The manuscript "
Synthesis, properties and adsorption kinetic study of new cross-linked composite materials based on polyethylene glycol polyrotaxane and polyisoprene/semi-rotaxane " is based on the synthesis, characterisation and aaplication of composite materials based on polyethylene glycol polyrotaxane and polyisoprene/semi-rotaxane. There are some improvements can be done before it can be accepted for publication.
First of all, the data is handled very poorly. like, can be seen in arranging the figures and writing the text too. (Need some separation among the figures of SEM ans Fig S4.
The abstract should clearly state the essence of the problem the authors are addressing, what the authors did and what was found and recommend. That will help a prospective reader of the abstract to decide if they wish to read the entire article.
Please provide a schematic diagram of theme of this article in one figure.
Please remove those general statements which are less significant, redundant phrases, and also informal writing style.
Need to mark the peaks in Fig 1.
The results and discussion section is very poor so need to revise properly with adding appropriate references.
Need to add rectify all typo, super and sub-script errors.
Need to replace the figures with high quality.( Resolutions of figures can be improved).
Introduction section must be written in better way, it is so lengthy. Please update comparable references with some other applications of materials too like Key Engineering Materials 920, 36-42, Research on Chemical Intermediates 45, 2927-2945, Journal of alloys and compounds 535, 44-49, Journal of hazardous materials 264, 481-489, Nanomaterials 12 (8), 1355.
Add the AFM graph for better understanding of this study.
Need to elaborate the application in better way for easy understanding towards reader.
What is the need of Figure S3?
Conclusion should be based on some numerical results.
Need to improve the English language though out the article.
Need to improve the English language though out the article.
Author Response
We thank you for the constructive criticism and suggestions, which are valuable and improve the quality of our paper.
The answers required by the reviewer are now included in the main text in blue color.
Q1: First of all, the data is handled very poorly. like, can be seen in arranging the figures and writing the text too. (Need some separation among the figures of SEM ans Fig S4.)
Answer Q 1: We agree with the reviewer’s remark and the Figure 3 was placed in the supplementary information, and Figure 4 became Figure 3, and we have arranged the text in order to be more comprehensible.
Q2: The abstract should clearly state the essence of the problem the authors are addressing, what the authors did and what was found and recommend. That will help a prospective reader of the abstract to decide if they wish to read the entire article.
Answer Q2: We have modified the abstract in order to be more comprehensible for the readers.
Q3: Please provide a schematic diagram of theme of this article in one figure.
Answer Q3: We now added a graphical abstract for our manuscript, as reviewer suggested.
Q4: Please remove those general statements which are less significant, redundant phrases, and also informal writing style.
Answer Q4: We have revised the introduction part and all the changed are marked in blue color.
Q5: Need to mark the peaks in Fig 1.
Answer Q1: We have marked the peaks on the Figure 1 as reviewer suggested.
Q6: The results and discussion section is very poor so need to revise properly with adding appropriate references.
Answer Q6: We agree with the reviewer’s remarks. The materials presented in this these manuscript are quite new in the field of supramolecular materials based on cross-linked polyrotaxane or semi-polyrotaxanes and it is a relative low number of the literature references in this case (for example in the case of the polyisoprene polyrotaxanes only 3 references could be found).
Q7: Need to add rectify all typo, super and sub-script errors.
Answer Q7: We have corrected the typos and now are marked in blue color in the main manuscript.
Q8: Need to replace the figures with high quality.( Resolutions of figures can be improved).
Answer Q8: We have replaced all the figures from the main manuscript with high resolution figures.
Q9: Introduction section must be written in better way, it is so lengthy. Please update comparable references with some other applications of materials too like Key Engineering Materials 920, 36-42, Research on Chemical Intermediates 45, 2927-2945, Journal of alloys and compounds 535, 44-49, Journal of hazardous materials 264, 481-489, Nanomaterials 12 (8), 1355
Answer Q9: We included in the manuscript two representative references that reviewer recommended. The references are marked in blue color in the main manuscript as ref 24 and 28.
Q10: Add the AFM graph for better understanding of this study.
Answer Q10: We performed the AFM studied on the materials. The 2D AFM topography images are included in the main manuscript as Figure 3 and the surface roughness parameters are summarized in Table 2. The AFM results are added in blue color at page 6.
The surface morphologies of the composite films were also investigated by AFM and SEM microscopies. The AFM microscopy was used to analyze the phase and surface topography of composites films in order to attest the presence of the PI/HPβCD SR into the PEG matrix. The 2D topography images and the roughness parameters are shown in Fig. 3 and summarized in Table 1. The surface pattern of the pure cross-linked material 1 indicated microphase separation, which may be attributed to the packing of the PEG uncovered segments and the PEG segments encapsulated into HPβCD. The surface of the pure cross-linked material appeared to be more rough having the values of the average roughness (Sa) and the root-mean-square roughness (Sq) 70.69 and 89.02 nm. In contrast the surfaces of the composite materials 2 and 3 appeared to be smoother after incorporation of the PI/HPβCD SR into the matrix. Additionally, with the increased concentration of PI/HPβCD SR the Sq values decreases from 64.73 nm for the 2 material to 58.16 nm in case of composite material 3. This result is an indication that the presence of PI/HPβCD SR has a beneficial effect in obtaining more homogeneous composite materials.
Q11: Need to elaborate the application in better way for easy understanding towards reader.
Answer Q11: In this manuscript we present our results on the synthesis, characterization and the preliminary kinetic MB dye adsorption study for the supramolecular materials obtained by cross-linking of polyrotaxane with a semi-polyrotaxane. These new supramolecular materials have been characterized from the structural and morphological point of view in order to demonstrate the successful synthesis of such materials; afterwards, we studied their applicability as sorbents for the MB dye from aqueous solutions.
Q12: What is the need of Figure S3?
Answer Q12: Figure S3 had become Figure S4 in the supplementary information. In order to perform the adsorption kinetic study we first have to measure the maximum wavelength of MB aqueous solution at different concentration using UV-vis spectroscopy. We start our experiment using a 5 mg/L concentration solution of MB. In order to measure the kinetic of adsorption aliquots are taken from the dye solution at different contact times and the concentration of the MB was determined by UV-vis at λmax. From the plot representation of the absorption versus concentration of the solution (the calibration curve) we can calculate the slope, which is further use to determine the concentration of the solution during the adsorption experiment. Based on this information we can calculate the adsorption capacity (qt) of the material.
Q13: Conclusion should be based on some numerical results.
Answer Q13: We agree with the reviewer remark and we revised the conclusion part.
Q14: Need to improve the English language though out the article.
Answer Q14: We have revised the English language of our manuscript.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
This paper reports the synthesis of two composites materials obtained by means of cross-linking reaction with HMDI between the PEG/HPβCD polyrotaxane with 5 and 10 wt% of PI/HPβCD 60 SR.
These materials were completely characterized from physico-chemical and morphological points of view and the results were compared to those of the pure cross-linked material. Additionally, the composite with 10 wt% of PI/HPβCD SR was preliminarily tested as a sorbent for the adsorption of the methylene blue dye (MB) at the solid/liquid interface.
The work is well written and the results were described clearly. I recommend the publication of the current work after the following minor revisions
Below few comments and questions for the authors are reported:
1 the introduction of the paper could be improved. More description of the existing cross-linked systems should be included.
2 preliminary adsorption tests using the composite with 10 wt% of PI/HPβCD SR, towards MB were performed. Could the authors show the comparison between these results with the adsorption capacity of the pure cross-linked film 1, obtained by the cross-linking only of PEG/HPβCD polyrotaxanes chains?
3 TGA analysis is a useful method for the investigation of the species involved. Could the authors report (maybe in the supplementary materials), the TGA traces including the derivatives?
Author Response
We thank you for the constructive criticism and suggestions, which are valuable and improve the quality of our paper.
The answers required by the reviewer are now included in the main text in blue color.
Below few comments and questions for the authors are reported:
Q1: The introduction of the paper could be improved. More description of the existing cross-linked systems should be included.
Answer Q 1: We have now revised the introduction part of the manuscript according to all reviewers’ recommendations.
Q2: preliminary adsorption tests using the composite with 10 wt% of PI/HPβCD SR, towards MB were performed. Could the authors show the comparison between these results with the adsorption capacity of the pure cross-linked film 1, obtained by the cross-linking only of PEG/HPβCD polyrotaxanes chains?
Answer Q2: The adsorption tests were performed only for the material that contained 10 wt% of PI/HPβCD SR in the matrix as it is mention in the chapter 3.1. Adsorption kinetics. From the structural, morphological and thermal characterization performed, we found that the pure cross-linked material 1 does not have a porous morphology and more than that the AFM reveals a microphase separation and also this material has the lower thermal stability in comparison to the composite materials.
Q3: TGA analysis is a useful method for the investigation of the species involved. Could the authors report (maybe in the supplementary materials), the TGA traces including the derivatives?
Answer Q3: We agree with the reviewer’s recommendation a the TG derivative was add as Figure S4 in the supplementary material.
Author Response File: Author Response.pdf
Reviewer 3 Report
Subject: Review of Manuscript Submission materials-2540758
I have carefully reviewed the manuscript titled " Synthesis, properties, and adsorption kinetic study of new cross-linked composite materials based on polyethylene glycol polytrioxane and polyisoprene/semi-rotaxane" submitted to Materials for consideration. This article develops new composite materials, prepared by cross-linking of polymers. And further evaluated the structural, morphological, and thermal properties. This material is aimed to possess superior thermal stability and dye adsorption capacity. This paper is innovative in the development of polymer. However, further supplementation is needed for dye adsorption and/or degradation.
It can be accepted after major revision.
1. Methylene blue has a certain ability of self-degradation and photodegradation, so the author should add a light avoidance test phase in addition to balancing time before the test, which should be reflected in the discussion part of the paper and the details of the experiment.
2. For dye degradation or adsorption tests, the stability of the sample is crucial. Therefore, the author should test the MB adsorption rate of the sample under the same conditions. Meanwhile, the additional XRD is recommended to measure the characteristics of the sample after several circles.
3. DSC signals reveal interesting results. Did the authors consider that these materials might be potential dielectric or pyroelectric materials? Because the DSC curve seems to have thermal hysteresis. If it is a pyroelectric material, then its piezoelectric properties may facilitate the dissociation of contaminants under external field conditions (such as visible-light irradiation or ultrasound), not just the adsorption of MB.
4. Figure 3 and Figure 4 need to be merged, or one of them needs to be placed in the SI. At the same time, the particle size or pore size should be marked in the SEM.
5. The XRD pattern of sample 3 should indicate the properties or groups of corresponding peaks in the picture, instead of only being explained in the article. This is also for the convenience of readers.
6. The image format should be consistent. For example, Figure 2 does not include a top border and a right border, as well as Figure 8. In addition, the left margin of sample 1 in Figure 2 should be reduced appropriately.
Author Response
We thank you for the constructive criticism and suggestions, which are valuable and improve the quality of our paper.
The answers required by the reviewer are now included in the main text in blue color.
Q1: Methylene blue has a certain ability of self-degradation and photodegradation, so the author should add a light avoidance test phase in addition to balancing time before the test, which should be reflected in the discussion part of the paper and the details of the experiment.
Answer Q 1: We agree with the reviewer’s remark, indeed MB dye may undergo self-degradation and photodegradation under visible light. Studies have been performed in this view and demonstrated that after 240 min of exposing MB aqueous solution under visible light the concentration the dye decrease with 5% from the total concentration. This information was included in the Characterization chapter in blue color and the new references 27, 28 were added.
Q2: For dye degradation or adsorption tests, the stability of the sample is crucial. Therefore, the author should test the MB adsorption rate of the sample under the same conditions. Meanwhile, the additional XRD is recommended to measure the characteristics of the sample after several circles.
Answer Q 2: We have performed XRD difractogram AFM microscopy of the 3 composite materials after three cycles of adsorption/desorption of MB. The SEM and WAXS images are included as Fig. S6 and S7 in the supplementary material. Our new comments are marked in blue color at the page 14.
Additionally, we underwent three cycles of adsorption -desorption of MB in order to test the reusability of the material. The above experiments were performed on the same experimental condition. The adsorption capacity after the third experiment decreased from 2.58 to 1.76 mg g-1. To further examine if chances in the morphology of the film occurred, AMF and WAXS were also performed. The 2D AFM image (Fig. S7) showed a slight microphase separation, while the roughness parameter indicated that the surface became smoother in comparison to the initial material, the Sa decrease from 58.16 to 54.43 nm. The WAXS pattern (Fig. S8) indicated a drop in diffraction intensities and shift on the crystallinity the peaks. The initial material exhibited the reflection peaks at 2θ = 19.32o and 23.53o, while after the adsorption -desorption process an intense peak is observed at 2θ = 11.98o, which may be attributed an ordered packing of the polyrotaxanes in the supramolecular material, and an amorphous hallow at 2θ = 20.54o. Based on the obtained results we can assume that this composite material based on the cross-linked rotaxanes architectures can be utilized for the adsorption of MB dye from aqueous solutions. This is a preliminary study and additional investigations are in due course.
Q3: DSC signals reveal interesting results. Did the authors consider that these materials might be potential dielectric or pyroelectric materials? Because the DSC curve seems to have thermal hysteresis. If it is a pyroelectric material, then its piezoelectric properties may facilitate the dissociation of contaminants under external field conditions (such as visible-light irradiation or ultrasound), not just the adsorption of MB.
Answer Q 3: We agree with the reviewer remark, these materials might be dielectric materials. We are taken into consideration to test their dielectric properties. We appreciate the reviewer suggestion.
Q4: Figure 3 and Figure 4 need to be merged, or one of them needs to be placed in the SI. At the same time, the particle size or pore size should be marked in the SEM.
Answer Q 4: We agree with the reviewer remark and now we placed Figure 3 in the supporting information as Figure S3. We did not marked the pore sizes in the SEM figure, because the to the pore sizes that we measures in SEM using ImageJ online software, we have applied a statistical correction as we mention in the main manuscript at page 6. This statistical correction was introduced since it was very likely that the measured pore diameters d, to be smaller than the true diameter D and because this statistical correction assumed that the pores are spherical and the equatorial diameter, D, of a spherical void is related to the diameter d measured from SEM image, by a parameter h. This parameter represents the distance of d from the center of the sphere. The relationship between these parameters is given in the Equation 1:
(1)
Assuming that the average value of h = D⁄2, the Equation 1 became:
(2)
This correction was applied to all the measured diameters in order to obtain the equatorial diameter D.
Q5: The XRD pattern of sample 3 should indicate the properties or groups of corresponding peaks in the picture, instead of only being explained in the article. This is also for the convenience of readers.
Answer Q 5: We added in the Figure 1 the groups of corresponding peaks as reviewer suggested.
Q6: The image format should be consistent. For example, Figure 2 does not include a top border and a right border, as well as Figure 8. In addition, the left margin of sample 1 in Figure 2 should be reduced appropriate.
Answer Q 6: We have modified the figures according to the reviewer’s remark.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
need to revise further with taking care of typo anf grammatical errors.
need to revise with taking care of typo anf grammatical errors.
Author Response
We thank you once again for the constructive suggestions that helped us to improve the quality of our paper.
We have revised the English language of our manuscript, and all the modifications are now included in the main text in red color.
Reviewer 3 Report
I am satisfied with the authors' responses, and I recommend the publication of the revised manuscript.
Author Response
We will like to express our gratitude to reviewer #3, for the appreciation of our work.
