Progressive Review of Functional Nanomaterials-Based Polymer Nanocomposites for Efficient EMI Shielding

Round 1

Reviewer 1 Report

This paper systematically and comprehensively summarized the current research progress of mainstream EMI materials from the perspectives of traditional materials, metamaterials, CNT, nanomaterials, mxene and polymer nanocomposites:

(1) In Figs.3, 6, 8 and 11, the resolution of these images are low and  it is difficult to read the detailed content;

(2) Why the unit of thickness of CNT/PI/PVP is mg*m-3 in Table 1? It is suggested that the unit of thickness should be unified in Table 1.

 (3) In Fig.4, it is wrong to simply consider MOF as a 2D material. It is generally believed that MOFs taking metal ions as connection points and organic ligands support to form three-dimensional materials with pore structure

Author Response

Reviewer #1

This paper systematically and comprehensively summarized the current research progress of mainstream EMI materials from the perspectives of traditional materials, metamaterials, CNT, nanomaterials, mxene and polymer nanocomposites:

Response: We appreciate your compliments and suggestions very much. In response to your valuable comments, we have revised the revised manuscript.

Comment 1:  In Figs.3, 6, 8 and 11, the resolution of these images are low and  it is difficult to read the detailed content;

Response: We appreciate your valuable suggestion. We have incorporated the high-resolution images.

Comment 2: Why the unit of thickness of CNT/PI/PVP is mg*m-3 in Table 1? It is suggested that the unit of thickness should be unified in Table 1.

Response: Your suggestion is greatly appreciated. We have unified the units in Table 1.

Comment 3: In Fig.4, it is wrong to simply consider MOF as a 2D material. It is generally believed that MOFs taking metal ions as connection points and organic ligands support to form three-dimensional materials with pore structure

Response: We are in total agreement with the learned referee that all MOF are not 2D nanomaterial, we would like to mention that we have referred the following for our consideration:

1. Soc. Rev., 2018,47, 6267
2. https://doi.org/10.1016/j.cej.2022.134692
3. https://doi.org/10.1016/j.cej.2022.134692
4. DOI:10.1039/D0DT01882A

Author Response File: Author Response.docx

Reviewer 2 Report

This paper reviews nanomaterials-based polymer nanocomposites for EMI shielding applications. The overall idea of this manuscript is clear and the logic is reasonable. I recommend this manuscript can be accepted after a mandatory revision. The detailed comments are listed as follows, 

1. In order to deal with the EM interference problem, the EM shielding materials and EM absorbing materials have been studied and applied. Shielding effectiveness is used to evaluate the EM shielding materials, while the reflection loss is used to evaluate the EM absorbing materials. Shielding effectiveness includes absorption shielding effectiveness and reflection shielding effectiveness. What relationship between absorption shielding effectiveness and absorbing property of absorbing materials? Some references about electromagnetic wave absorption are recommended to be cited: Hierarchically porous Co/C nanocomposites for ultralight high-performance microwave absorption, https://doi.org/10.1007/s42114-020-00202-z; Metal-organic framework derived hollow CoFe@C composites by the tunable chemical composition for efficient microwave absorption, https://doi.org/10.1016/j.jcis.2021.02.120;

2. Several review articles have been cited in the References section; however, the authors should introduce the differences between your review paper and these cited review paper. By this way, the necessity and significance of your review can be obviously shown.

3. I want to discuss with the authors, what methods do you think is beneficial to further improving the EMI performance, which is beneficial to the future investigation?

4. The English writing should be further polished in the revision. There are some errors in this manuscript.

5. Some relevant latest references about electromagnetic performance are recommended to be cited: Flexible polystyrene/graphene composites with epsilon‑near‑zero properties, https://doi.org/10.1007/s42114-022-00486-3; Recent Advances in radio-frequency negative dielectric metamaterials by designing heterogeneous composites, https://doi.org/10.1007/s42114-022-00479-2; 

Overall, this paper may be important to give some citations. However, the quality needs be improved, especially the background needs be strengthened with the above recommended references. I would like to review a revised one.

Author Response

This paper reviews nanomaterials-based polymer nanocomposites for EMI shielding applications. The overall idea of this manuscript is clear and the logic is reasonable. I recommend this manuscript can be accepted after a mandatory revision.

We appreciate the helpful feedbacks and suggestions that have revised the manuscript according to them while preparing a point-by-point response to each comment.

Comment 1: In order to deal with the EM interference problem, the EM shielding materials and EM absorbing materials have been studied and applied. Shielding effectiveness is used to evaluate the EM shielding materials, while the reflection loss is used to evaluate the EM absorbing materials. Shielding effectiveness includes absorption shielding effectiveness and reflection shielding effectiveness. What relationship between absorption shielding effectiveness and absorbing property of absorbing materials? Some references about electromagnetic wave absorption are recommended to be cited: Hierarchically porous Co/C nanocomposites for ultralight high-performance microwave absorption, https://doi.org/10.1007/s42114-020-00202-z; Metal-organic framework derived hollow CoFe@C composites by the tunable chemical composition for efficient microwave absorption, https://doi.org/10.1016/j.jcis.2021.02.120;

Response: The relationship between absorption shielding effectiveness and absorbing property of absorbing materials is explained

The shielding effectiveness due to absorption comes from the inherent absorption of the radiation arising out of the electric and magnetic dipoles interacting with the incident radiation. The penetration depth of the radiation assumes significance in this aspect. With higher level of absorption resulting in the thickness of the material greater than the penetration depth, the absorption increases exponentially with increase in thickness. When the penetration depth is higher than the thickness of the sample, the multiple reflections between the front and back interfaces increases the path length, thereby enhancing the total absorption.  For every reflection into the bulk of the material at the interfaces, the amount of absorption enhances the shielding exponentially. In the case of nano-composites, the presence of scatterers as fillers improves the path length. This would enhance the shielding due to absorption.

The References mentioned by the learned referee is cited in the revised manuscript.

Comment 2: Several review articles have been cited in the References section; however, the authors should introduce the differences between your review paper and these cited review paper. By this way, the necessity and significance of your review can be obviously shown

Response: The significance of our review is shown by introducing the differences.

Over the years wide range of polymer composites have been explored for EMI shielding. In the last decade the emergence of nanomaterials with multitude possibilities enabled various researchers to explore the possibilities of polymer nanocomposites for EMI shielding. The published review articles pertain to standalone polymer -carbon nanotubes, polymer – graphene materials and admixture of various 2D nanomaterials. However, we have focused on host of polymers with carbon nanotubes with various weight fraction, Graphene as the reinforcement material in the macromolecular matrix and more significantly emerging 2D nanomaterials-based polymer nanocomposites.

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Comment 3: I want to discuss with the authors, what methods do you think is beneficial to further improving the EMI performance, which is beneficial to the future investigation?

Response: The possible ways of enhancing EMI performance for futuristic design of shielding materials are shown below and included in the revised manuscript

. While the shielding is due to the reflection and absorption, one can improve the shielding by:

1. a) Enhancing the internal path length with the presence of scatterers. The morphology of the scatterers plays a crucial role in the amount of scatterers for an effective shielding.
2. b) Alignment of conducting nano-rods enhances reflection-based shielding while retaining low amount of fillers.
3. c) For absorption dominant shielding, the presence of magnetic nano particles is desirable. Additionally, surface modification enhances the scattering at the surface thereby reducing the amount of radiation entering the shield.

Comment 4: The English writing should be further polished in the revision. There are some errors in this manuscript

Response: We appreciate the valuable suggestion and have polished our work using language correction software tools.

Comment 5: Some relevant latest references about electromagnetic performance are recommended to be cited: Flexible polystyrene/graphene composites with epsilon‑near‑zero properties, https://doi.org/10.1007/s42114-022-00486-3; Recent Advances in radio-frequency negative dielectric metamaterials by designing heterogeneous composites, https://doi.org/10.1007/s42114-022-00479-2; 

Response: We have incorporated the latest references, as advised by the reviewer.

Comment 6: Overall, this paper may be important to give some citations. However, the quality needs be improved, especially the background needs be strengthened with the above recommended references   

Response: We greatly appreciate your suggestion. We have now revised the manuscript accordingly and included in the manuscript with appropriate citations

Historically, metal-based composites were used as the predominant material for EMI shielding by the virtue of their superior electrical conductivity, mechanical properties, and permeability, however they were met with challenges of corrosion and lack of mechanical flexibility by the metallic fillers. To meet the criterion of paramount EMI shielding effectiveness tailored   functional materials with outstanding properties are designed for efficient EMI shielding. Reflection, which is the primary mechanism of shielding, must have enough electrical conductivity and for the secondary mechanism due to absorption comes from the inherent interaction of the radiation arising out of the electric and magnetic dipoles with the incident radiation. The penetration depth of the radiation assumes significance in this aspect.  With higher level of absorption resulting in the thickness of the material greater than the penetration depth, the absorption increases exponentially with increase in thickness. When the penetration depth is higher than the thickness of the sample, the multiple reflections between the front and back interfaces increases the path length, thereby enhancing the total absorption.  For every reflection into the bulk of the material at the interfaces, the amount of absorption enhances the shielding exponentially.

Reflection dominant shielding materials give rise to secondary interference of EM waves with mere deflection of EM waves, alternately the absorption dominant shielding materials get rid of EM waves through ohmic and thermal losses. To reach this goal of creating materials with the required attributes, a wide range of polymer nanocomposites are desired  for EMI shielding with adequate impedance matching, high attenuation capabilities, wider absorbing bandwidth , lower thickness and good thermal conductivity. In the case of nano-composites, the presence of scatterers as fillers improves the path length. This would enhance the shielding due to absorption. The shielding effectiveness due to reflection is a function of the ratio of conductivity and permeability of the material. The shielding effectiveness due to absorption depends upon the thickness and attenuation constant of the material. Additionally, reflections at numerous interfaces inside the material also contributes to the shielding effectiveness which depends on the sample thickness. The multiple reflection depends on the sample thickness. The excellent EMI shielding material possess outstanding impedance matching attributes which depends on the permittivity and permeability. The size, thickness, and shape of the nanomaterials impact the permeability and henceforth resulting shielding effectiveness.

Over the years wide range of polymer composites have been explored for EMI shielding. In the last decade the emergence of nanomaterials with multitude functionalities enabled various researchers to explore the possibilities of polymer nanocomposites for EMI shielding. The ease of dispersion of carbonaceous fillers in the macromolecular matrix  and the resulting manifestation of the  conductive network  makes the Carbon based fillers one of the ideal candidates for lightweight EMI shielding materials  Several polymer nanocomposites with prudent blends of  fillers, such as carbon nanofibers, carbon nanotubes, metal nanowires, graphene, reduced graphene oxide, hBN MoS₂ ,MXene, magnetic fillers Fe₃O₄ ,Fe₂O₃ nickel ferrite have been extensively used for designing efficient EMI shielding materials.The published review articles pertain to standalone polymer -carbon nanotubes, polymer – graphene materials and admixture of various 2D nanomaterials. Our review focuses on various polymers blended with carbon nanotubes of various weight fraction, Graphene as the reinforcement material in the macromolecular matrix and more significantly emerging 2D nanomaterials based polymer nanocomposites.

Author Response File: Author Response.docx

Reviewer 3 Report

Review of progressive review of functional ……..

The paper is a good review of nanomaterials for EM shielding and could be published with minor edits. Some comments are given below.

In abstract: The technology changes ….. sentence is not clear.

Grammar could be improved in a few places in paper.

P 2. Another important aspect is the environmental aspect of these shielding materials. Not clear. Do you mean: The environmental impact of manufacturing shielding materials should be minimized.

Figure 2 could be explained more, e.g. how do the properties such as dielectric properties affect SE? How do dipoles shield EM waves?

P 4. The exceptional mechanical properties ………… It seems nanoparticles are considered but not macroscale materials. Nanoparticles usually have matrix material between the particles which limits conductivity and strength. Carbon nanotube sheets provide a greater increase in strength and electrical conductivity than nanoparticles I think. The paper could have a section on macroscale assemblages of nanoparticles for shielding.

P 4. Metamaterials. Why is artificial materials terminology used? Do you mean synthetic materials?

P 4. Above equation 4.4. the text equation 5.3 should be 4.3.

For the non expert, it may help to explain the properties of classes of materials more, Fig 3.

P 6. Sentence, “effortless percolation” is not clear.

P 6. “Offering less interphase resistance” – this can be achieved by using macroscale sheets of nanoparticles and could be discussed in the paper.

P 7. Layered with elevated specific surface area, does elevated mean increased?

P 7. Increases manifold, does manifold mean greatly?
It is not clear to me how layered nanomaterials increases surface area?

P 9. Which are small defects, can you explain more what you mean by defects?

P 10. Renders totality to an integral architecture, not clear.

P 10. Exemplify profound reasoning, not clear.

P 10. How is surface area computed for Mxenes?

P 13. Can you explain more about interfacial polarization loss and defect polarization?

Do you consider how the density of the composite changes when metal particles are added?

I thought attenuation of EM waves occurs because the wave couples to a conductive material and an electric current is induced in the material. Since the material has electrical resistance, the current dissipates electrical energy as heat. The size, thickness and shape of the nanoparticles or film affect how well waves couple to the material and affect the electrical conductivity of the bulk material. If this is correct, could the basic principles of shielding be explained a bit more in the paper?

Author Response

The paper is a good review of nanomaterials for EM shielding and could be published with minor edits. Some comments are given below

Response: We greatly appreciate your compliments and suggestions. Taking into consideration your valuable suggestions, we have revised the revised manuscript and made necessary changes.

Comment 1: In abstract: The technology changes ….. sentence is not clear.

Grammar could be improved in a few places in paper

Response: We appreciate your thoughtful suggestion. The sentence in the abstract is reframed All grammatical errors and the text format have been corrected.

The unprecedented technological revolution is driving people to adapt for miniaturized electronic gadgets.

Comment 2: P 4. The exceptional mechanical properties ………… It seems nanoparticles are considered but not macroscale materials. Nanoparticles usually have matrix material between the particles which limits conductivity and strength. Carbon nanotube sheets provide a greater increase in strength and electrical conductivity than nanoparticles I think. The paper could have a section on macroscale assemblages of nanoparticles for shielding.

Response: Thanks for your valuable suggestion. We have considered 2D nanomaterials.

The exceptional mechanical properties of two-dimensional (2D) nanomaterials (tensile strength ~130 GPa), and unique electrical properties (mobility~10000 Cm² V^-1 S^-1)  have made them an ideal candidate as fillers in nanocomposite-based EMI shielding.

We are not dealing with macroscale assemblages of nanoparticles, we would like to inform that we will consider it for our future work

Comment 3: P 4. Metamaterials. Why is artificial materials terminology used? Do you mean synthetic materials?

Response: Thanks for your queries. Kindly find the answers listed below.

Metamaterials are artificial arrangement of structures that are periodic in nature and sub-wavelength in dimension. These structures can be designed and fabricated using dielectric and conducting materials. Metamaterials, in a way, is synthetic as they are not occurring in a natural process.

Comment 4: P 4. Above equation 4.4. the text equation 5.3 should be    4.3. For the non expert, it may help to explain the properties of classes of materials more, Fig 3.

Response: Thanks for your valuable suggestion. We have corrected the said equation number in the text.

As per the suggestion the equation number is modified and classes of materials are explained

DPS (Double positive material) is one where both permittivity (ε) and permeability (μ) are positive. These materials are commonly available dielectrics which are abundant in nature.

ENG (Epsilon Negative material) has the permittivity (ε) negative and permeability (μ) positive. These are called electrical metamaterials. The noble metals fall in this category and they occur in a limited manner in nature.

DNG (Double Negative material) has permittivity (ε) and permeability (μ) less than zero, which is negative. They do not occur in nature. They belong to a category called negative index metamaterial, which do not occur in nature and are man-made materials.

MNG (Mu Negative material) is a type of material which has permittivity (ε) positive and permeability (μ) negative. They are also called as magnetic metamaterials.

Comment 5: P 6. Sentence, “effortless percolation” is not clear

Response: Thanks for your valuable suggestion. We have explained as shown below.

So, it is reasonable to gain a higher conductivity by thinner and longer CNT, because the big networks significantly transfer the electrons within nanocomposite increasing the conductivity

Yasser, Z.,Kyong, Y. R., A simple methodology to predict the tunnelling conductivity of polymer/CNT nanocomposites by the roles of tunneling distance, interphase and CNT waviness, RSC Adv., 7, 34912,2017

Comment 6: P 6. “Offering less interphase resistance” – this can be achieved by using macroscale sheets of nanoparticles and could be discussed in the paper

Response: Your suggestion is greatly appreciated.

A thicker and more-conductive interphase introduces a more-conductive nanocomposite, while thin and poor-conductive interphase cannot improve the conductivity. As a result, it is important to provide strong interphase regions in PCNT to grow the conductivity

Razavi, R., Zare, Y., Rhee, K.Y., A two-step model for the tunneling conductivity of polymer carbon nanotube nanocomposites assuming the conduction of interphase regions. RSC. Adv.  7,50225-50233,2017

We are not dealing with macroscale assemblages of nanoparticles; we would like to inform that we will consider it for our future work

Comment 7: P 7. Layered with elevated specific surface area, does elevated mean increased?

Response: Thanks for your query.

Yes, enhanced specific surface area and accordingly changed in the manuscript.

Comment 8: P 7. Increases manifold, does manifold mean greatly? It is not clear to me how layered nanomaterials increases surface area?

Response: We appreciate your valuable feedback. We have mentioned on the basis of literature citations.

In comparison with zero-dimensional (0D) and one-dimensional (1D) materials, 2D layered materials possess several extraordinary advantages. 2D layered materials have larger specific surface areas as compared to their bulk structures

^a.Low, J., Cao, S., Yu, J.,Wageh, S., Two-dimensional layered composite photocatalysts, Chem. Commun., 50, 10768-10777,2014

^b.Khossossi ,N., Singh, D., Ainane, A., Ahuja, R., Recent progress of defect chemistry on 2D materials for advanced battery anodes, Chem. Asian. J. 15,21,3390–404,2020.

^c.Chang,M., Jia, Z.,He,S., JZhou,J., Zhang,S., Tian,M., Wang,B., Wu,G., Two-dimensional interface engineering of NiS/MoS2/Ti3C2Tx heterostructures for promoting electromagnetic wave absorption capability, Comp. Part B: Eng., 225,109306,2021.

Comment 9: P 9. Which are small defects, can you explain more what you mean by defects?

Response: Thanks for your valuable suggestion. We have incorporated the explanation as below

Defects are structural imperfections- In essence the real crystal is always idealistic and crystal imperfections are pragmatic. Basically there are three kinds of imperfections that can materialize in crystals: point defects, line defects, and plane defects.

Jurgen, S.,Stefan, K.E., Perspectives on the Theory of Defects, Front. Mater., 5 ,2018

Comment 10: P 10. Renders totality to an integral architecture, not clear.

Response: We appreciate the query and we have explained as shown below

class I, organic and inorganic components are embedded and only weak bonds (hydrogen, van der Waals or ionic bonds) give the cohesion to the whole structure.

Comment 11: P 10. Exemplify profound reasoning, not clear.

Response: Thanks for the suggestion. Profound reasoning is explained as shown below

The lamellar nanocomposites exhibit better understanding of interphase interactions between the phases in polymer nanocomposites

Comment 12: P 10. How is surface area computed for Mxenes?

Response: We appreciate the query and we have explained as shown below

The N2 adsorption-desorption analysis obtained by the Brunauer, Emmett and Teller (BET) method is used for computation of surface area of Mxenes

(https://doi.org/10.1051/e3sconf/202125202068, Materials , 13, 2347,2020)

Comment 13:  P 13. Can you explain more about interfacial polarization loss and defect polarization?

Do you consider how the density of the composite changes when metal particles are added?

Response: We appreciate the query and we have explained as shown below

The EM waves attenuation occurs via  space charge polarization, orientation polarization, which is a manifestation of interfacial polarization along with dielectric relaxation and defect polarization..Remarkably, the increase in interfacial area increases the interfacial polarization and the associated loss, which encourages the effective absorption of the incident EM wave. solitary electron pairs or unsaturated bonds appear at the edge of the vacancy sites, and these defects can be generated as dipole centers to form a strong dipole relaxation effect. The dipoles created under the external electric field can improve the electron migration rate and induce the occurrence of dipole relaxation, thus enhancing the conduction loss and relaxation polarization. Owing to the high specific surface area, 2D nanomaterials are likely to produce enormous amount of dipole moments affecting the dipole polarization.

Vineeta,S.,Review of electromagnetic interference of shielding materials fabricated by iron ingredients, Nanoscale Adv.,  1, 1640,2019.

Liang, Z., Julong H., Xingang, W., Hongbo, W., Zhenjun, W., Zhuo, Li., Hongqian, Z., Wenyu, Mu., Dielectric properties and electromagnetic interference shielding effectiveness of Al2O3-based composites filled with FeSiAl and flaky graphite, J.Alloys. Comp., 829,154556,2020.

Khossossi ,N., Singh, D., Ainane, A., Ahuja, R., Recent progress of defect chemistry on 2D materials for advanced battery anodes, Chem. Asian. J. 15,21,3390–404,2020.

Chang,M., Jia, Z.,He,S., JZhou,J., Zhang,S., Tian,M., Wang,B., Wu,G., Two-dimensional interface engineering of NiS/MoS2/Ti3C2Tx heterostructures for promoting electromagnetic wave absorption capability, Comp. Part B: Eng., 225,109306,2021.

The electrical conductivity of composites is determined by the establishment of conductive networks The amount of filler at which the conductivity networks are formed in the macromolecular matrix called the percolation threshold. By adding appropriate fillers and ensuring apt dispersion of the fillers the percolation threshold can be attained leading to increase in EMI shielding in polymer nanocomposites. The density and size of nanoparticles inversely affect the number of particles in polymer nanocomposites at a constant filler concentration the interfacial area reduces by increasing the size and density of nanoparticles which will impact the EMI shielding effectiveness

Shi, Y.-D., Li, J., Tan, Y.-J., Chen, Y.-F.,Wang, M., Percolation Behavior of Electromagnetic Interference Shielding in Polymer/Multi- Walled Carbon Nanotube Nanocomposites. Compos. Sci. Technol. 170, 70−76,2019.

Ashraf, M.A., Peng, W., Zare, Y.,Rhee, K.Y., Effects of Size and Aggregation/Agglomeration of Nanoparticles on the Interfacial/Interphase Properties and Tensile Strength of Polymer Nanocomposites. Nanoscale. Res. Lett. 13, 214,2018

Comment 14: I thought attenuation of EM waves occurs because the wave couples to a conductive material and an electric current is induced in the material. Since the material has electrical resistance, the current dissipates electrical energy as heat. The size, thickness and shape of the nanoparticles or film affect how well waves couple to the material and affect the electrical conductivity of the bulk material. If this is correct, could the basic principles of shielding be explained a bit more in the paper?

Response: Thanks for your valuable suggestion. We have explained as shown below

We completely agree with the learned referee that the size, thickness and shape of the nanoparticles or film affect the electrical conductivity of the bulk material.

The shielding effectiveness due to reflection is a function of the ratio of conductivity and permeability of the material. The shielding effectiveness due to absorption depends upon the thickness and attenuation constant of the material. Additionally, reflections at numerous interfaces inside the material also contributes to the shielding effectiveness which depends on the sample thickness. The multiple reflection depends on the sample thickness.. The excellent EMI shielding material possess outstanding impedance matching attributes which depends on the permittivity and permeability. The size, thickness, and shape of the nanomaterials impact the permeability and henceforth resulting shielding effectiveness.

Author Response File: Author Response.docx

Reviewer 4 Report

Many references related to the topic need to be cited. The following are suggested to be included:

https://doi.org/10.1021/am200021v

https://doi.org/10.1002/adma.201305293

https://doi.org/10.1016/j.carbon.2013.04.008

https://doi.org/10.1016/j.matchemphys.2008.08.065

https://doi.org/10.1021/am4036527

https://doi.org/10.1002/adfm.201702807

https://doi.org/10.1016/j.compositesa.2019.105670

https://doi.org/10.1016/j.carbon.2016.04.052

https://doi.org/10.1039/C8TC05955A

https://doi.org/10.1016/j.cej.2019.122622

https://doi.org/10.1002/adma.201907499

DOI: 10.1126/sciadv.abj1663

The manuscript contains large paragraphs of other articles/Theses, so plagiarism was detected. This is very clear in the paragraph of “Metamaterials”. In addition, the citation within the text does not correspond to the one that should. For example, Ref13 should be a study of 1999, yet, a publication of 2020 is given in the References part.

In addition, the flow of discussion and the structure is a bit chaotic, does not help the reader to assess the quality of the review article. Thus, rejection is suggested for the submitted draft. Major changes need to be done.

Author Response

Many references related to the topic need to be cited. The following are suggested to be included:

https://doi.org/10.1021/am200021v

https://doi.org/10.1002/adma.201305293

https://doi.org/10.1016/j.carbon.2013.04.008

https://doi.org/10.1016/j.matchemphys.2008.08.065

https://doi.org/10.1021/am4036527

https://doi.org/10.1002/adfm.201702807

https://doi.org/10.1016/j.compositesa.2019.105670

https://doi.org/10.1016/j.carbon.2016.04.052

https://doi.org/10.1039/C8TC05955A

https://doi.org/10.1016/j.cej.2019.122622

https://doi.org/10.1002/adma.201907499

DOI: 10.1126/sciadv.abj1663

Response: We appreciate your suggestion. The suggested references are cited in the revised manuscript.

Comment 2: The manuscript contains large paragraphs of other articles/Theses, so plagiarism was detected. This is very clear in the paragraph of “Metamaterials”. In addition, the citation within the text does not correspond to the one that should. For example, Ref13 should be a study of 1999, yet, a publication of 2020 is given in the References part

Response: Thanks for your valuable suggestion. We have modified the respective section “Metamaterials”. Also, citations in the text and references are matched.

Comment 3: In addition, the flow of discussion and the structure is a bit chaotic, does not help the reader to assess the quality of the review article. Thus, rejection is suggested for the submitted draft. Major changes need to be done

Response: Thanks for your valuable suggestion. We have now revised the manuscript accordingly.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

It can be accepted in its current form.

Reviewer 2 Report

The comments have been addressed. It can be accepted.

Reviewer 3 Report

Added background information improves the paper for non experts.

Reviewer 4 Report

May be accepted in the revised form