Smart and Economic Conductive Textile for Electromagnetic Interference Shielding

Smart and Economic Conductive Textile for Electromagnetic Interference Shielding

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ScienceDirect

Available online at www.sciencedirect.com

ScienceDirect

Procedia Engineering 00 (2017) 000–000

Available online at www.sciencedirect.com

www.elsevier.com/locate/procedia

Procedia Engineering 00 (2017) 000–000

ScienceDirect

www.elsevier.com/locate/procedia

Procedia Engineering 216 (2017) 93–100

9th International Conference on Materials for Advanced Technologies (ICMAT 2017)

Smart and Economic Conductive TextileTechnologies for Electromagnetic 9th International International Conference on on Materials for for Advanced Advanced Technologies (ICMAT2017) 2017) 9th Conference Materials (ICMAT Interference Shielding Smart and Economic Conductive Textile for a1Electromagnetic a b K. Sarkar , D. Das , S. Chattopadhyay Interference Shielding Rubber Technology Centre, India. a Indian Institute b of Technology,Kharagpur-721302, a1 b Department of Jute and Fibre Technology, Calcutta University-700019, India.

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K. Sarkar , D. Das , S. Chattopadhyay

Rubber Technology Centre, Indian Institute of Technology,Kharagpur-721302, India. b Department of Jute and Fibre Technology, Calcutta University-700019, India.

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Abstract

Carbon black particles are stabilized into the macro-structured clustered composite form by using natural rubber Abstract latex, polyvinyl alcohol, and others additives. Newly developed macro-structured carbon clusters are applied on the various types of wovenare fabric by theinto knife-over-roll coating technique develop conductive cotton fabric. The Carbon black particles stabilized the macro-structured clusteredtocomposite form by using natural rubber surface morphology of the coated fabrics is characterized by FESEM and AFM. The morphological study confirmed latex, polyvinyl alcohol, and others additives. Newly developed macro-structured carbon clusters are applied on the the presence of clustered nature of carbon particles on the surface of the fabric. The electromagnetic interference various types of woven fabric by2 the knife-over-roll coating technique to develop conductive cotton fabric. The shielding effectiveness (EMISE ) of the conductive fabrics are assessed using vector network analyzer. The surface morphology of the coated fabrics is characterized by FESEM and AFM. The morphological study confirmed scattering parameters of the two antenna analyzer are used to calculate the EMISE of all the fabrics. The effect of the presence of clustered nature of carbon particles on the surface of the fabric. The electromagnetic interference the structure is studied for the highest EMISE taking plain, twill and satin designed fabrics. Moreover, the various shielding effectiveness (EMISE 2 ) of the conductive fabrics are assessed using vector network analyzer. The parameters such as a real density, thread density, thickness of the base fabric are systematically varied to achieve scattering parameters of the two antenna analyzer are used to calculate the EMISE of all the fabrics. The effect of optimal EMISE. The satin designed fabric has performed better as the shield (22 dB) among the three basic weaves the structure is studied for the highest EMISE taking plain, twill and satin designed fabrics. Moreover, the various used in the investigation. The maximum reflected portion of the electromagnetic interference shielding is observed parameters such as a real density, thread density, thickness of the base fabric are systematically varied to achieve when the satin designed fabric is used as base fabric. The EMISE of the coated fabrics is proportionally increased optimal EMISE. The satin designed fabric has performed better as the shield (22 dB) among the three basic weaves with increases in the areal density, thread density, and thickness. used in the investigation. The maximum reflected portion of the electromagnetic interference shielding is observed when the satin designed fabric is used as base fabric. The EMISE of the coated fabrics is proportionally increased © 2017 The Authors. Published by Elsevier Ltd. with increases in the areal density, thread density, and thickness. Selection and/or peer-review under responsibility of the scientific committee of Symposium 2017 ICMAT. © 2017 The Authors. Published by Elsevier Ltd. © 2017 The Authors. Published by Elsevier Ltd. Selection and/or peer-review under responsibility of the scientific committee of Symposium 2017 ICMAT. Selection and/or peer-review under responsibility of the scientific committee of Symposium 2017 ICMAT.

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Corresponding Author: Dr Santanu Chattopadhyay. Tel.: (+91) 03222281758 (O), 03222281759(R), 9434055304 (mob); Fax: +91-3222-82292, Email: [email protected]

1 2Corresponding

Author: Dr Santanu Chattopadhyay. Tel.: is (+91) 03222281758 (O), 03222281759(R), 9434055304 (mob); Fax: Electromagnetic interference shielding (EMI shielding) the custom of surrounding electronic devices with a material sheet+91-3222-82292, to protect against Email: [email protected] outgoing as well as incoming emissions of electromagnetic radiation. „Electromagnetic interference shielding effectiveness (EMISE)‟ is the measurement of the difference of the electromagnetic signal‟s intensity before and after shielding. 2 Electromagnetic interference shielding (EMI shielding) is the custom of surrounding electronic devices with a material sheet to protect against outgoing as©well incoming 1877-7058 2017asThe Authors.emissions Publishedofbyelectromagnetic Elsevier Ltd. radiation. „Electromagnetic interference shielding effectiveness (EMISE)‟ is the measurement of the differenceunder of theresponsibility electromagnetic signal‟s intensity beforeofand after shielding. Selection and/or peer-review of the scientific committee Symposium 2017 ICMAT. 1877-7058 © 2017 The Authors. Published by Elsevier Ltd. Selection and/or peer-review under responsibility of the scientific committee of Symposium 2017 ICMAT.

1877-7058 © 2017 The Authors. Published by Elsevier Ltd. Selection and/or peer-review under responsibility of the scientific committee of Symposium 2017 ICMAT. 10.1016/j.proeng.2017.10.1118

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Keywords: Coating; Nanocomposite; EMISE; Fabric; Parameters.

1.

Introduction:

In the high-tech era, the use of electronic devices is overgrowing day by day. Thus, the amount of radiation from the devices will be increased exponentially with the days to come. The performance of one device may be affected by the other [1]. Moreover, it is also a matter of concern to the different kind of health issues [2]. It is well accepted that the electromagnetic radiation may have an adverse effect on the health of mankind [3] including trees [4], birds [5], animals [6], etc. Thus, the attempt to have protection against the electromagnetic interference (EMI) as well as radiation have initiated by the researcher from the last few decades. For the above purpose, textile fabric is a good choice [7] due to its flexible nature, low cost, availability, etc. As we know, to use the textile fabric as electromagnetic interference shield, it should have reasonable conductivity [8] for the electric current. Unfortunately, natural textile itself is nonconductive. Therefore, attempt to develop conductive textile has become an interesting field of research. Jagatheesan K et al. [9] has reviewed all the attempts to develop conductive fabric and their effectiveness as EMI shield. Palanisamy S et al. [10] have analyzed the fiber-based structure for EMI shielding taking woven, non-woven, knitted, foils, etc. Rajendrakumar K et al. [11] have also studied the effect of structural parameters of metallic wire/core spun knitted fabrics. But, the development of electromagnetic interference shield fabric using normal grade carbon black nanoparticles is not well known. The effectiveness of a newly developed conductive fabric [12] as EMI shield is investigated in the present work taking only the different types of woven fabrics. In the study, the effect of the structure (weave types/design), as well as fabric parameters (areal density, thread density, thickness) on the EMISE is investigated for the highest EMI shielding. 2. Experimental: 2.1 Materials: The various woven cotton fabrics are used as based fabric. Carbon nanocomposites are prepared using High Abrasion Furnace (HAF, N330) carbon black, Natural Rubber Latex (NRL), hydrolyzed (89-90%) Polyvinyl Alcohol (PVA) and Glutaraldehyde (25%). 2.2 Methods: 2.2.1 Application of conductive nanocomposites on cotton fabric NRL is mixed with 15% (w/v) aqueous solution of PVA (180 phr, per 100 gram of NRL) under high-speed stirring. Then 300 phr of HAF (N330) is added stepwise and mixed thoroughly to make a homogeneous mixture. At last, 3 phr of glutaraldehyde (25%) is added to the mixture. Finally, the nanocomposite in paste form is applied to the various cotton fabric with the help of a „knife-over-roll‟ (Schematic is shown in figure-1) coating machine [12]. Coated cotton fabrics are then dried and cross-linked simultaneously at 140oC for 2 hours.

Figure 1: Schematic of „Knife-over-roll‟ coating technique.



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3. Testing and Characterization: 3.1 Field Emission Scanning Electron Microscopy (FESEM): Scanning electron microscope (Zeiss-Merlin) is used to observe the surface morphology of the coated fabric. The conductive fabric is coated with gold (10 nm thickness) before taking the image. The micrograph is taken by applying 5 kV electric field. 3.2 Atomic Force Microscopy (AFM): The surface topography of the coated fabric is characterized using atomic force microscope (Agilent Technology, 5500 AFM). The measurement is done using tapping mode with force constant of 48 N/m. The Si3N4 is used as the tip material. The tip curvature length is less than 10 nm, and cantilever length is less than 100 µm while taking the image. 3.3 Electromagnetic Interference Shielding Effectiveness (EMISE): Electromagnetic interference shielding effectiveness of the various coated conductive fabrics is measured using Agilent (9226A, VNA). FieldFox microwave VNA with type-N(f) test port connector is used for 2-port S-parameter measurements. The „CalReady‟ 2-port full calibration is done before taking the value of the S-parameters. The rectangular fabric sheet is placed in between the coax-to-waveguide adopter attached to each port while measuring the S-parameters. 4. Results and Discussion: 4.1 Field Emission Scanning Electron Microscopy: The nanocomposite is applied on the surface of the cotton fabrics with the help of knife-over-roll coating technique in layers. The final surface morphology is shown in figure-2. It is prominent that the carbon particles are distributed in a unique fashion which we termed as “macro-structured carbon clusters.” The unique uniform manner of the carbon particles results in making the surface appreciably conductive. Thus, the coated fabric becomes suitable for electromagnetic interference shielding application.

Figure 2: FESEM images of coated conductive fabric developed using carbon nanocomposite

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4.2 Atomic Force Microscopy: The surface characteristic of the coated conductive fabric also studied by atomic force microscope. The roughness profile of a coated fabric is shown in figure-3. The apparently smooth surface of the conductive fabric is rough. The nanoscale roughness of the fabrics is observed to be changed with changes in design as well as the numbers of coats applied to the base fabric. Say, the ultimate coating thickness of a conductive fabric is 100 microns. The final thickness can be achieved by applying the single coat, double, triple, and so on. If the number of the coating is increased, then roughness of the coated surface decreases that ultimately affect the performance of the fabric as EMI shield. The reflection, as well as absorption of the electromagnetic interference/radiation is noticed to be changed with changes in the surface nature of the shielding fabric.

Figure 3: AFM topographical image and roughness profile of the same surface.

4.3 Electromagnetic interference shielding effectiveness (EMISE) measurements. The EMISE of the conductive fabric is assessed by using Agilent N9926A instrument at room temperature at the frequency range of 8.2 to 12.4 GHz. It is calculated from the measured S-parameters of a vector network analyzer following the standard formulas [13] (1) The total EMISE (T) = 10 log10[1/|S12|2] =10 log10 [1/|S21|2] (2) EMISE (A) = 10 log10[1/(1-|S11|2)] (3) EMISE (R) = 10 log10[(1-|S11|2)/|S12|2] and A+R=T (4) The total EMISE (T) has three components namely absorption (A), reflection (R) and multiple internal reflections (M). The multiple reflection loss „M‟ is neglected (i.e M=0 dB, because T≥ 10 dB) while calculating the „A‟ and „R‟. 4.4 Effect of the various parameters of fabric on electromagnetic interference shielding effectiveness. The equal (100±10 micron) thin layer of the macro-structured carbon clusters composite is applied on the various fabric. The basic weaves, i.e., plain, twill and satin are selected to observe the changes in the EMISE. The apparent



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surface of the different chosen designs is depicted in figure 4. The areal density (gram per square meter, GSM) of the three different types of fabric is kept almost constant. The EMISE obtained is shown in figure-5(a-c). The changes in EMISE depending the fabric design is shown in figure-5(a). It is evident that the satin fabric shows

Figure 4: The schematic of the basic weaves taken in the study.

highest EMISE whereas plain gives the lowest. The possible reason may be a slight difference (table-1) in the thickness of the fabric although they have equal GSM. The second reason may be the surface nature of the woven fabrics. It is a well-known fact that the surface smoothness is increased with increasing the floating point. The plain weave has the least float as compare to twill and satin. Due to the highest floating points and higher thread density, the satin fabric becomes smoother among the three designed used in the study. As a result, the coated surface of the fabric also becomes smoother. Thus, the reflected amount of EMI is observed to be the higher in the case of satin fabric. Therefore, the total EMISE of the satin fabric becomes the highest. The reflection (R) and absorption (A) portions of all the fabrics are shown in figure-5(b, c, and d). It is very interesting to observe that the total EMISE of all the fabrics remains almost unaffected with the increasing frequency in the range used (8.2-12.4 GHz). But, the reflection portion of all the fabric is decreased, and absorption portion is increased with increasing the frequency. It is also noticeable that the „R‟ and „A‟ portions have oscillated in a complementary fashion (if R increased, A decreased and vice-versa at a particular frequency) within some ranges. These ranges become wider with increasing frequency ultimately become fixed. The macro-structured carbon clusters are firmly bounded by the flexible blended matrix of NRL and PVA. Thus, the vibratory electromagnetic field may have sufficient energy to oscillate the nanostructured carbon particles but failed to break the film barrier within the range used. The plain woven fabric is selected to observe the effect of the areal density of the fabric on EMISE. The GSM of the fabric is varied by changing the weft yarn density. The details of all the fabric taken are listed in table-2. The effect of areal density (GSM) on the EMISE is shown in figure-6. It is evident that the EMISE of fabric is increased with the increasing GSM of the base fabric used to develop conductive fabric. The thickness of the fabric also changes with variations in the weft yarn density. Thus, both parameters of fabric become necessary for application as shielding fabric. One thing should be remembered that the GSM of the fabric is varied by changing the yarn density not by changing the yarn diameter. If GSM is varied by changing the yarn size or diameter, then the scenario will be different. We did not study this aspect.

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Figure 5: a) EMISE with the different weaves, b), c) and d) Absorption and Reflection portion of total EMISE of satin, twill and plain respectively.

Figure 6: Areal density (GSM) vs. EMISE

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Table 1: The details of the different designed fabric.

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Table 2: The details of the plain fabric with varied GSM.

5. Conclusions: The EMISE of the coated conductive fabric is dependent on the design, areal density and the thickness of the base fabric along with the parameters of the composites used to make the conductive fabric. In the present study, only the fabric parameters are considered. The EMISE remains almost unaffected by the frequency changes in case of all the fabrics. The absorption portion of the EMISE is increased, and reflection portion is decreased with increasing the frequency of the applied electromagnetic field. Satin design shows the highest EMISE among plain, twill and satin fabric. The EMISE is proportionally increased with increasing GSM, thread density, and thickness of the base fabric. Acknowledgement We are grateful to the Indian Institute of Technology Kharagpur, India, for providing the full financial support & all kind of facilities. We are also thankful to Dept. of Jute and Fibre Technology, University of Calcutta, for allowing us to do some portion of the work. References [1] Cheng L, Zhang T, Guo M, Li J, Wang S, Tang H. Electromagnetic shielding effectiveness and mathematical model of stainless steel composite fabric. The Journal of The Textile Institute. 2015 Jun 3;106(6):577-86. [2] Hwang PW, Chen AP, Lou CW, Lin JH. Electromagnetic shielding effectiveness and functions of stainless steel/bamboo charcoal conductive fabrics. Journal of Industrial Textiles. 2014 Nov;44(3):477-94. [3] Gherardini L, Ciuti G, Tognarelli S, Cinti C. Searching for the perfect wave: the effect of radiofrequency electromagnetic fields on cells. International Journal of Molecular Sciences. 2014 Mar 27;15(4):5366-87. [4] Balodis V, Brūmelis G, Kalviškis K, Nikodemus O, Tjarve D, Znotiņa V. Does the Skrunda Radio Location Station diminish the radial growth of pine trees? Science of the Total Environment. 1996 Feb 2;180(1):57-64. [5] Everaert J, Bauwens D. A possible effect of electromagnetic radiation from mobile phone base stations on the number of breeding house sparrows (Passer domesticus).Electromagnetic Biology and Medicine. 2007 Jan 1;26(1):63-72. [6] Balmori A. Electromagnetic pollution from phone masts.Effects on wildlife.Pathophysiology. 2009 Aug 31;16(2):191-9. [7] Sonehara M, Noguchi S, Kurashina T, Sato T, Yamasawa K, Miura Y. Development of an electromagnetic wave shielding textile by electroless Ni-based alloy plating. IEEE Transactions on Magnetics. 2009 Oct;45(10):4173-5. [8] Chung DD. Electromagnetic interference shielding effectiveness of carbon materials.Carbon. 2001 Feb 28;39(2):279-85. [9] Jagatheesan K, Ramasamy A, Das A, Basu A. Fabrics and their composites for electromagnetic shielding applications. Textile Progress. 2015 Apr 3;47(2):87-161. [10] Palanisamy S, Tunakova V, Militky J. Fiber-based structures for electromagnetic shielding–comparison of different materials and textile structures. TextileResearch Journal. 2017 Jun 17:0040517517715085.

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[11] Rajendrakumar K, Thilagavathi G. A study on the effect of construction parameters of metallic wire/core spun yarn based knitted fabrics on electromagnetic shielding. Journal of Industrial Textiles. 2013 Apr;42(4):400-16. [12] Sarkar K, Das D, Chaki TK, Chattopadhyay S. Macro-structured carbon clusters for developing waterproof, breathable conductive cotton fabric. Carbon. 2017 May 31;116:1-14. [13]M. H. Al-Saleh, W. H. Saadeh, and U. Sundararaj, EMI shielding effectiveness of carbon based nanostructured polymeric materials: A comparative study, Carbon, 2013, 60, 146 –156.