Wideband Radar Absorbing Structure Using Polyaniline-Graphene Nanocomposite
Round 1
Reviewer 1 Report
The paper „Wideband radar absorbing structure using Polyaniline-Graphene nano composite “ is devoted to the design and preparation of the radar shielding structure. The paper is well-organized and will be interesting to readers of C. However some parts may be improved.
The introduction part is clearly written and delivers a scientific problem. However, RAMs are applied to reduce not only reflected but also transmitted power. Several materials and techniques are effective for both cases at the same time, for instance, 10.1063/1.5093421, 10.1088/1361-6463/AB86E6.
The Choice of conducting polymers part backgrounds the polymer selection and the modification of the polymer with graphene.
“These effects result in the increase in conductivity of the composite in the off-plane direction.” Do you expect your composite to have the anisotropy of the conductivity?
What is the scientific background behind the layered structure with the golden ratio?
Some typos should be fixed:
Figure 1. please update the legend and add (a)-(d) to SEM images. Since now there are 4 SEMs and only two of them are described in the legend.
Line 180 antennasconnected space is needed.
Author Response
Response to Reviewer 1 Comments
Point 1: The introduction part is clearly written and delivers a scientific problem. However, RAMs are applied to reduce not only reflected but also transmitted power. Several materials and techniques are effective for both cases at the same time, for instance, 10.1063/1.5093421, 10.1088/1361-6463/AB86E6.
Response 1: The need for attenuating the transmitted power alongside the reflected power was included in the introductory part with citations (line:15) pointing to the use of non-organic materials for absorption alongside reflection as in https://0-doi-org.brum.beds.ac.uk/10.1063/1.5093421. Similarly, the recent importance given to additive manufacturing in microwave absorbers was cited (line: 29) with more literature for instance as in https://0-doi-org.brum.beds.ac.uk/10.1088/1361-6463/ab86e6.
Point 2: The Choice of conducting polymers part backgrounds the polymer selection and the modification of the polymer with graphene.
“These effects result in the increase in conductivity of the composite in the off-plane direction.” Do you expect your composite to have the anisotropy of the conductivity?
Response 2: The off-plane direction here refers to the atomic scale off-plane direction of a graphene sheet and not that of the actual absorber structure. This ambiguity in the manuscript has now been corrected by specifically rephrasing the statement (line: 129). The effect of anisotropy in the atomic scale on the microwave scale is not significant as these molecular domains are random. The enhancement brought about in the off-plane direction can only contribute to a better bulk conductivity and not any form of anisotropy in microwave scale.
Point 3: What is the scientific background behind the layered structure with the golden ratio?
Response 3: Golden ratio has been widely considered across many scientific disciplines for various analysis for both natural and human-made systems. Golden ratio and Fibonacci series are used in machine learning problems, stock market predictions, iterative algorithms, fractal structures etc. This has been explained with citations (line: 178).
Point 4: Figure 1. please update the legend and add (a)-(d) to SEM images. Since now there are 4 SEMs and only two of them are described in the legend.?
Response 4: Corrected the legends for SEM images (Figure 1) with descriptions.
Point 5: Line 180 antennasconnected space is needed.
Response 5: Corrected the typographic error.
Reviewer 2 Report
The manuscript titled “Wideband radar absorbing structure usingPolyaniline-Graphene nano composite” concerns a wideband non resonant absorber and its radar cross section reduction. The objective of the work is to demonstrate the use of non-metallic conducting polymer composites devoid of metals for radar absorbing materials structural designs. The structure is an all-polymer and electrically thin design with a potential to be 3D printed to suit the target object.
The manuscript reviews an important conducting polymer application topic. The paper is well-written, and well-discussed. However, it fails in demonstrating the advantages of the investigated setup with respect to similar schemes. Authors should show the benefits of their development according to these known from literature. Authors also have focused only on the oldest known CPs (polyaniline), there are still important but for sure there are not “new brand” of CPs any more. Due to the fact, authors should emphasize their innovation. According to that manuscript may be ready for publication after minor revision.
Author Response
Response to Reviewer 2 Comments
Point 1: The manuscript reviews an important conducting polymer application topic. The paper is well-written, and well-discussed. However, it fails in demonstrating the advantages of the investigated setup with respect to similar schemes. Authors should show the benefits of their development according to these known from literature. Authors also have focused only on the oldest known CPs (polyaniline), there are still important but for sure there are not “new brand” of CPs any more. Due to the fact, authors should emphasize their innovation..
Response 1: Polyaniline is one of the oldest intrinsically conducting polymers that are still widely used owing to its environmental stability, availability of cheap raw materials, low cost synthesis and a vast literature. The shortcoming of Polyaniline is its lower conductivity which are solved by newer conducting polymers like poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). Unfortunately their microwave applications are limited by the huge cost per gram when compared to Polyaniline. In this work, we have used Polyaniline-Graphene composite as an alternative material to bridge this at a significantly lower cost. This has now been added in the manuscript for better clarity with citations to recent works on PEDOT:PSS (line:152).
Reviewer 3 Report
This paper demonstrated the use of non-metallic conducting polymer composites devoid of metals for RAM structural designs, which is interesting. Some comments are given as below:
Some of the abbreviations are not defined in the manuscript, for example, RAM in the abstract, FSS in the introduction section, and TE mode and TM mode in the main text.
Figure 1, the labels of a and b are missing.
Please explain the doped and dedoped states and the preparation procedures of the PANi-graphene composites in more detail.
In sections 2 and 3, the related literature review, experimental procedures and results are mixed up, which is a bit difficult to follow.
Please give a short literature review on how 3D printing has been used to produce radar absorbing structures. Some review paper might be helpful, for example, Tan et al. Recent Progress on Polymer Materials for Additive Manufacturing. Advanced Functional Materials (2020): 2003062. In addition, the outlook of how 3D printing can be used to produce the all-polymer non-resonant wideband absorber based on the developed Polyaniline-Graphene nanocomposites can be discussed in detail.
Author Response
Response to Reviewer 3 Comments
Point 1: Some of the abbreviations are not defined in the manuscript, for example, RAM in the abstract, FSS in the introduction section, and TE mode and TM mode in the main text.
Response 1: The abbreviations have now been defined (Line: 8, 25, 202).
Point 2: Figure 1, the labels of a and b are missing.
Response 2: Corrected the legends for SEM images (Figure 1) with descriptions.
Point 3: Please explain the doped and dedoped states and the preparation procedures of the PANi-graphene composites in more detail.
Response 3: This section has been elaborated more with clarity. The procedure is detailed in our previous work on the synthesis and characterization of PANi-Graphene composite which has now been cited in this section (Line: 159).
Point 4: In sections 2 and 3, the related literature review, experimental procedures and results are mixed up, which is a bit difficult to follow.
Response 4: The section 2 is a preface to the design of absorber and the experimental background pertaining to it. Section 3 marks the start of the design related to the absorber, which is the focus. More clarity has been added into the section 3 by rephrasing it (Line: 152).
Point 5: Please give a short literature review on how 3D printing has been used to produce radar absorbing structures. In addition, the outlook of how 3D printing can be used to produce the all-polymer non-resonant wideband absorber based on the developed Polyaniline-Graphene nanocomposites can be discussed in detail.
Response 5: The literature on 3D printing for microwave has now been added to the manuscript with citation to recent review literature (Line: 29). The prospective application of 3D printing of PANi-Graphene composite has now been discussed (Line: 147).
