Fabrication and characterization of Screen-printed Graphite and
Nickel Based Thick Film Resistive Strain Sensor.
Abstract: - Piezo resistive properties of thick film resistors are shown by a variety of nanomaterials, in
which graphite and nickel are used to study the piezo resistive response in this paper. The present work
proposes to fabricate stain sensor on substrates like PVC, and transparent plastic sheet. Screen printing
method is used for patterning of sensor on the substrates with two different inks namely piezo resistive ink
made of graphite and nickel powder and conductive ink made of silver. Change in resistance of the
fabricated sensor is noted for the changes in force applied on the sensor and corresponding gauge factor is
observed to be around 10.5 and 11 for PVC and OHP respectively. The screen-printed strain gauge
performance is investigated and presented in this paper. This study of mechanical test results demonstrate
that the sensor can be used for micro strain detection in various applications.
Key-Words: - Piezo resistive, gauge factor, flexible sensor, screen printing, strain sensor, thick film
resistor.
Received: January 12, 2023. Revised: November 15, 2023. Accepted: December 14, 2023. Published: January 16, 2024.
1. Introduction
Flexible strain sensors have promising applications
in the field of healthcare, wearable electronics,
automotive, human motion detection, robotics etc.
after the discovery of nanomaterials [1]–[5]. High
sensitivity, flexibility, good stretchability and
durability are some of the essential properties that
are considered while fabricating any sensor.
Many nanomaterials and nanocomposites such as
CNTs, Graphene, graphene oxide, carbon black,
carbon nanofibers, carbon Ni composite, are
investigated to observe piezo resistive, piezo
capacitive and piezoelectric effects [6]–[13]. Among
them Nickel and graphite are also found to be strain
sensitive material and they are used with other
materials to enhance the piezo resistive nature of the
overall compound [9], [14]–[16]. The effect of
nickel particles in the composite enhances the piezo
resistive effect of the compound [16]–[18] and the
property is enhanced when there is change in
temperature[19], [20]. In this paper, a composite of
nickel nanoparticles and graphite is used as sensing
material on a flexible substrate and the change in
resistance for mechanical deformation is
investigated and studied.
Depending on the applications and range of
production of sensors, the materials and fabrication
technique will be chosen. Inkjet printing[21], screen
printing [1], [22], 3D printing [34], laser induction
and gravure printing , soft lithography, drop casting,
spray coating, spin coating, direct dry transfer etc.
K. SAUJANYA B. POORNAIAH
Department of Instrument Technology Department of ECE
AUCE(A), Andhra University L. B. Reddy College of Engineering
Visakhaptnam, Andhra Pradesh Mylavaram, Krishna District, AP
INDIA INDIA
A. KAMALA KUMARI Y. SRINIVASA RAO
Department of Instrument Technology Department of Instrument Technology
AUCE(A), Andhra University AUCE(A), Andhra University
Visakhaptnam, Andhra Pradesh Visakhaptnam, Andhra Pradesh
INDIA INDIA
International Journal of Chemical Engineering and Materials
DOI: 10.37394/232031.2024.3.1
K. Saujanya, B. Poornaiah,
A. Kamala Kumari, Y. Srinivasa Rao
E-ISSN: 2945-0519
1
Volume 3, 2024
Fig. 2: Screen printed samples, left are PVC sheet and
right are OHP sheet
[23], [24] are some technologies for printed
electronics on substrates. The advances in screen
printing technologies provide many excellent
advantages like cost effectiveness, throughput, ease
in fabrication, and many more[1]. In the present
work screen printing technique is used for printing
of strain sensors on flexible substrates. The screens
are made on A4 size with 200 mesh detailed at 45
lines per inch. Screen printing method provides the
researcher an ease in fabrication of sensor and the
advantages of this method encouraged us to use the
method in this work.
When a stress is applied on the strain sensor
electrical parameter changes which is due to the
deformation in material. The mechanical
deformation can be applied on the sensor by
stretching, pressing, bending, tapping methods.
[25][26], [27] has used a Tensile test machine
experimental setup for mechanical analysis of the
sensor. [22] Reported strain sensing of a silver
carbon composite screen printed strain gauge on
TPU by applying different loads on the sensor to
observe the resistance changes. [28] Studied the
sensing behaviour of flexible conductive
PDMS/NCG nickel coated graphite composite
fabricated by natural sedimentation method. The
author reported resistance of the sensors were
increased and then decreased when the sensor was
under twisting, stretching and bending mode. [26]–
[28] used bending property for applying mechanical
strain to the sensor which were used mostly in
human motion detection and soft robotics. Another
method to give strain to the sensor is stretching, in
which force is applied in the opposite direction on
the sensor. This can be achieved on a Universal
Testing Machine that is reported by [29] for styrene
based ternary composite elastomer for
supercapacitor integrated strain sensor system, [30]–
Fig. 1: Schematic diagram illustrating the fabrication of strain sensor
International Journal of Chemical Engineering and Materials
DOI: 10.37394/232031.2024.3.1
K. Saujanya, B. Poornaiah,
A. Kamala Kumari, Y. Srinivasa Rao
E-ISSN: 2945-0519
2
Volume 3, 2024
[32] reported similar testing method for testing the
strain sensing of the composite materials. In this
investigation, the electromechanical behaviour of
the prepared sensor is being stretched using UTM
and relative change in resistance is observed.
In this work, a strain sensing resistor is fabricated
using the screen-printing method on a flexible
substrate that has nickel and graphite as sensing
material and silver as conductive material. The
strain response characteristics and stretchability of
the sensor is studied.
2. Experimental Section
2.1 Materials:
Nickel nanoparticle powder, graphite
powder and silver paste were purchased from
SILTECH CORPORATION INC, India. PVC (poly
vinyl chloride) powder is purchased from local
vendor, High purity solvent Cyclohexanone (00087)
purchased from Loba Chemie pvt. Ltd., India. Silver
conducting paste was utilized to fabricate
conductive contacts at the ends of the sensor.
Acetone is purchased for the cleaning of equipment
and substrates from sigma Aldrich.
Substrates used: PVC Sheet and transparent plastic
sheet are used as flexible substrates in this work.
All the materials and chemicals were used as
received without further purification.
2.2 Sensor Fabrication:
The schematic diagram of fabrication of strain
sensors is shown in Fig 1. Firstly, two screens are
prepared (one for conductive ink and other for
nickel graphite ink) with different patterns for the
printing process. Piezo resistive ink is prepared by
mixing 8g of graphite powder and 2g of nickel Nano
powder in planetary ball mill for 60 minutes. 2g of
PVC powder is added to the mixture and ball
milling is done for 30 min using 10 balls at 1000
rpm. 20 ml of cyclohexanone is mixed to the
powder to form a paste for screen printing.
Conductors are screen printed on the flexible
substrates using Silver conductive paste to evaluate
the performance of the sensor. Samples are cured at
1000C for 2 hours. Then piezo resistive ink is
printed to form a resistor in different patterns as
shown in Fig. 2. Curing at 1000C for 4 hours.
The screen-printed thick film resistors with 20mm
length and 10mm width (single resistor), 5mm x
5mm (series resistors) and bridge formation using
the first pattern on PVC sheets and transparent
plastic sheets are shown in Fig. 2. The nickel and
graphite powder have a particle size of 325 mesh
that is suitable for prepared screens for the printing
process. The thickness of the resistors on the
substrates is found to be 45μm using a thick film
Fig 3: Tensile testing of the sample on Universal Testing Machine Instron 5966 and a digital multimeter is
used to measure electrical resistance.
International Journal of Chemical Engineering and Materials
DOI: 10.37394/232031.2024.3.1
K. Saujanya, B. Poornaiah,
A. Kamala Kumari, Y. Srinivasa Rao
E-ISSN: 2945-0519
3
Volume 3, 2024
thickness measuring gauge.
2.3 Characterization
Morphological and structural studies of the
fabricated sensor were characterized by SEM
(ZEISS ULTRA55, INDIA). The Rigaku Smart Lab
XRD is used for chemical composition and
crystalline size of the material. FTIR (Fourier
Transform Infrared) spectra were recorded on
Perkin Elmer. Electromechanical studies of the
sensor are done by performing tensile testing on a
Universal Testing machine (INSTRON5966) and
electrical resistance for applied load is noted using a
digital multimeter as shown in Fig 3.
3. Results and Discussions
Characterization by XRD (X-ray Diffraction) was
carried out for the prepared sensor to observe the
structural analysis and crystallinity. The
corresponding spectra is shown in Fig 4 where the
large peak at 25.8 degrees and shorter peak at 44.38
degrees represents the presence of Graphite and
Nickel respectively. Individual XRD patterns of
nickel powder and graphite powder to study the
strain sensing behaviour are reported and
crystallinity is found to be 99.57% and 82%
respectively [13].
Fig 5 shows the SEM images of the Nickel graphite
composite screen-printed sensors on PVC substrate
before and after mechanical force applied on the
sensor. The images show that the low viscosity
composite is roughly and uniformly deposited on
the substrate which is due to curing of the sensors
after printing. A representative high magnification
view of Fig 5 (a) and (c) are shown in (b) and (d).
When mechanical strain is applied on the sensors
the conductive nature of the material reduces
resulting resistive behaviour. Fig 5 (c) and (d)
shows the morphology of the PVC strain sensor
after strain is applied on the sensor.
The electromechanical response of the strain sensor
printed on a flexible substrate by tensile test is done
on a Universal Test Machine Instron 5966. The
strain sensing measurement setup is shown in Fig 6.
Fig 5: The SEM images of Screen-printed strain
sensors on PVC film: (a) and (b) before stretching;
(c) and (d) after stretching
International Journal of Chemical Engineering and Materials
DOI: 10.37394/232031.2024.3.1
K. Saujanya, B. Poornaiah,
A. Kamala Kumari, Y. Srinivasa Rao
E-ISSN: 2945-0519
4
Volume 3, 2024
The prepared sensors were stretched with a constant
velocity of 0.5 mm/min on the UTM and the
resistance of the sensor was noted before stretching.
The applied force on the sensor was converted to
change in the original resistance which shows the
piezoresistive behaviour of the sensor. The
resistance is measured using a digital multimeter.
The response of strain vs change in resistance and
load vs resistance of the strain sensor on two
different flexible substrates are shown in Fig 6.
The Gauge factor of the sensor can be calculated
using following equations
𝐺𝑎𝑢𝑔𝑒 𝑓𝑎𝑐𝑡𝑜𝑟 = (∆𝑅/𝑅)
∈ (1)
Where,𝑆𝑡𝑟𝑎𝑖𝑛, ∈= ∆𝐿
𝐿, (2)
ΔR is change in resistance,
R is original resistance of the sensor,
ΔL is extension or change in length for applied load,
L is the original length of the sensor.
4. Conclusion
In this paper, the screen-printed strain
sensor using a Nickel-graphite composite is
demonstrated for measuring low to high strain by
observing the relative change in resistance of the
sensor. Gauge factor for PVC sheet is found to be
10.5 and for OHP sheet is 11. The results of the
electromechanical tests of printed strain sensor
indicates the strain sensing capability of the
prepared Ni-graphite composite material and this
sensor can be further be used in health monitoring
[35], electronic applications, gauges, medical
prosthetics, nanosensors, wearable electronics etc.
The studies of the fabricated sensor are so
promising that the sensor can further undergo
temperature sensitivity, durability and thickness
analyses. The fabricated sensor is providing GF near
to 11 that is comparable to previous studies [33]
which depends on the type of substrate used for
fabrication. The future work can be done to improve
the sensitivity and bendability of the sensor using
other flexible substrates like Polydimethylsiloxane
(PDMS), Polyimide, Fabrics etc. that can be used in
flexible and wearable electronic applications.
Acknowledgements
The portion of research was performed using
facilities at CeNSE, Indian Institute of Science,
Bengaluru, funded by Ministry of Human Resource
Development (MHRD), Ministry of Electronics and
Information Technology (MeitY), and Nanomission,
Department of Science and Technology (DST),
Govt. of India.”.
References
[1] N. Zavanelli and W. H. Yeo, “Advances
in Screen Printing of Conductive
Nanomaterials for Stretchable
Electronics,” ACS Omega, vol. 6, no. 14,
pp. 9" Review Review in preparation and
application of nickel-coated graphite
composite powder." 05 May. 2021,
https://www.sciencedirect.com/science/ar
ticle/pii/S0925838820343784. 344–9351,
2021, doi: 10.1021/acsomega.1c00638.
[2] V. J. Babu et al., “Intelligent
Nanomaterials for Wearable and
Stretchable Strain Sensor Applications:
The Science behind Diverse
Mechanisms, Fabrication Methods, and
Real-Time Healthcare,” Polymers
(Basel)., vol. 14, no. 11, 2022, doi:
10.3390/polym14112219.
Fig 6: The change in electrical resistance (ohms)
on application of load ranging from 0N to 150N
(left); the electrical resistance as a function of
strain for screen printed sensor on different
substrates (right)
International Journal of Chemical Engineering and Materials
DOI: 10.37394/232031.2024.3.1
K. Saujanya, B. Poornaiah,
A. Kamala Kumari, Y. Srinivasa Rao
E-ISSN: 2945-0519
5
Volume 3, 2024
[3] W. Liu et al., “Stable Wearable Strain
Sensors on Textiles by Direct Laser
Writing of Graphene,” ACS Appl. Nano
Mater., vol. 3, no. 1, pp. 283–293, 2020,
doi: 10.1021/acsanm.9b01937.
[4] L. E. Aygun et al., “Large-area resistive
strain sensing sheet for structural health
monitoring,” Sensors (Switzerland), vol.
20, no. 5, pp. 1–15, 2020, doi:
10.3390/s20051386.
[5] Z. Liu et al., Functionalized Fiber-Based
Strain Sensors: Pathway to Next-
Generation Wearable Electronics, vol.
14, no. 1. 2022.
[6] O. Kanoun, A. Bouhamed, R.
Ramalingame, J. R. Bautista-Quijano, D.
Rajendran, and A. Al-Hamry, “Review
on Conductive Polymer/CNTs
Nanocomposites Based Flexible and
Stretchable Strain and Pressure Sensors,”
Sensors, vol. 21, no. 2, pp. 1–29, 2021,
doi: 10.3390/s21020341.
[7] T. Yan, Z. Wang, and Z. J. Pan, “Flexible
strain sensors fabricated using carbon-
based nanomaterials: A review,” Curr.
Opin. Solid State Mater. Sci., vol. 22, no.
6, pp. 213–228, 2018, doi:
10.1016/j.cossms.2018.11.001.
[8] X. Zhang et al., “Flexible and high-
performance piezoresistive strain sensors
based on carbon
nanoparticles@polyurethane sponges,”
Compos. Sci. Technol., vol. 200, no.
September, p. 108437, 2020, doi:
10.1016/j.compscitech.2020.108437.
[9] D. D. L. Chung and X. Xi,
“Piezopermittivity for capacitance-based
strain/stress sensing,” Sensors Actuators
A Phys., vol. 332, p. 113028, 2021, doi:
10.1016/j.sna.2021.113028.
[10] H. Liu et al., “Flexible, Degradable, and
Cost-Effective Strain Sensor Fabricated
by a Scalable Papermaking Procedure,”
ACS Sustain. Chem. Eng., vol. 6, no. 11,
pp. 15749–15755, 2018, doi:
10.1021/acssuschemeng.8b04298.
[11] D. Zymelka, T. Yamashita, X. Sun, and
T. Kobayashi, “Printed strain sensors
based on an intermittent conductive
pattern filled with resistive ink droplets,”
Sensors (Switzerland), vol. 20, no. 15,
pp. 1–14, 2020, doi: 10.3390/s20154181.
[12] P. Walter et al., “CNT/Graphite/SBS
Conductive Fibers for Strain Sensing in
Wearable Telerehabilitation Devices,”
Sensors, vol. 22, no. 3, 2022, doi:
10.3390/s22030800.
[13] S. J. Lee, I. You, S. Kim, H. O. Shin, and
D. Y. Yoo, “Self-sensing capacity of
ultra-high-performance fiber-reinforced
concrete containing conductive powders
in tension,” Cem. Concr. Compos., vol.
125, no. November 2021, p. 104331,
2022, doi:
10.1016/j.cemconcomp.2021.104331.
[14] Y. Bai, F. Qin, and Y. Lu, “Lightweight
Ni/CNT decorated melamine sponge
with sensitive strain sensing performance
for ultrahigh electromagnetic absorption
in both GHz and THz bands,” Chem.
Eng. J., vol. 429, no. June 2021, p.
132393, 2022, doi:
10.1016/j.cej.2021.132393.
[15] R. Zhang et al., “Facile one-step
preparation of laminated PDMS based
flexible strain sensors with high
conductivity and sensitivity via filler
sedimentation,” Compos. Sci. Technol.,
vol. 186, no. July 2019, pp. 1–7, 2020,
doi: 10.1016/j.compscitech.2019.107933.
[16] J. W. Um, S. Y. Kim, B. H. Lee, J. B.
Park, and S. Jeong, “Direct writing of
graphite thin film by laser-assisted
chemical vapor deposition,” Carbon N.
Y., vol. 169, pp. 163–171, 2020, doi:
10.1016/j.carbon.2020.07.035.
[17] X. Xi and D. D. L. Chung, “Effect of
nickel coating on the stress-dependent
electric permittivity, piezoelectricity and
piezoresistivity of carbon fiber, with
relevance to stress self-sensing,” Carbon
N. Y., vol. 145, pp. 401–410, 2019, doi:
10.1016/j.carbon.2019.01.034.
International Journal of Chemical Engineering and Materials
DOI: 10.37394/232031.2024.3.1
K. Saujanya, B. Poornaiah,
A. Kamala Kumari, Y. Srinivasa Rao
E-ISSN: 2945-0519
6
Volume 3, 2024
[18] Š. Meškinis et al., “Giant Negative
Piezoresistive Effect in Diamond-like
Carbon and Diamond-like Carbon-Based
Nickel Nanocomposite Films Deposited
by Reactive Magnetron Sputtering of Ni
Target,” ACS Appl. Mater. Interfaces,
vol. 10, no. 18, pp. 15778–15785, 2018,
doi: 10.1021/acsami.7b17439.
[19] C. Karapepas, D. Nestler, D. Wett, and
G. Wagner, “Annealing effects of high
sensitive thin strain gauges consisting of
nickel carbon nanocomposites,” J. Reinf.
Plast. Compos., vol. 37, no. 22, pp.
1378–1384, 2018, doi:
10.1177/0731684418796309.
[20] C. Karapepas, D. Nestler, and G.
Wagner, “Influence of sputtering
temperature and layer thickness on the
electrical performance of thin film strain
sensors consisting of nickel-carbon
composite,” Key Eng. Mater., vol. 809
KEM, pp. 413–418, 2019, doi:
10.4028/www.scientific.net/KEM.809.41
3.
[21] T. K. Kang, “Inkjet printing of highly
sensitive, transparent, flexible linear
piezoresistive strain sensors,” Coatings,
vol. 11, no. 1, pp. 1–8, 2021, doi:
10.3390/coatings11010051.
[22] A. K. Bose et al., “Screen Printed
Silver/Carbon Composite Strain Gauge
on a TPU Platform for Wearable
Applications,” FLEPS 2020 - IEEE Int.
Conf. Flex. Printable Sensors Syst.,
2020, doi:
10.1109/FLEPS49123.2020.9239547.
[23] N. Ivanova, V. Gugleva, M. Dobreva, I.
Pehlivanov, S. Stefanov, and V.
Andonova, “We are IntechOpen , the
world ’ s leading publisher of Open
Access books Built by scientists , for
scientists TOP 1 %,” Intech, vol. i, no.
tourism, p. 13, 2016.
[24] M. J. Yee et al., “Carbon nanomaterials
based films for strain sensing
application—A review,” Nano-Structures
and Nano-Objects, vol. 18, p. 100312,
2019, doi:
10.1016/j.nanoso.2019.100312.
[25] D. Zymelka, T. Yamashita, X. Sun, and
T. Kobayashi, “Large-scale printed strain
sensors based on carbon ink incorporated
into an intermittent conductive silver
pattern,” Jpn. J. Appl. Phys., vol. 60, no.
SB, 2021, doi: 10.35848/1347-
4065/abd6db.
[26] A. Nag et al., “A Transparent Strain
Sensor Based on PDMS-Embedded
Conductive Fabric for Wearable Sensing
Applications,” IEEE Access, vol. 6, pp.
71020–71027, 2018, doi:
10.1109/ACCESS.2018.2881463.
[27] S. Zhao, P. Zheng, Q. Liu, L. Niu, H.
Cong, and A. Wan, “Highly stretchable
strain sensor with tunable sensitivity via
polydopamine template-assisted dual-
mode cooperative conductive network
for human motion detection,” Mater.
Des., vol. 206, p. 109780, 2021, doi:
10.1016/j.matdes.2021.109780.
[28] S. Li et al., “The tunable sensing
behaviors of flexible conductive
PDMS/NCG composites via regulation
of filler size prepared by a facile
sedimentation method,” Compos. Sci.
Technol., vol. 216, no. June, 2021, doi:
10.1016/j.compscitech.2021.109037.
[29] D. Park, Y. K. Park, S. Selvam, and J. H.
Yim, “Styrene-based ternary composite
elastomers functionalized with graphene
oxide-polypyrrole under iron(III)-alkyl
benzenesulfonate oxidants for
supercapacitor integrated strain sensor
system,” J. Energy Storage, vol. 51, no.
March, p. 104543, 2022, doi:
10.1016/j.est.2022.104543.
[30] S. Nuthalapati et al., “Highly sensitive,
scalable reduced graphene oxide with
palladium nano-composite as strain
sensor,” Nanotechnology, vol. 31, no. 3,
2020, doi: 10.1088/1361-6528/ab4855.
[31] P. Zhang et al., “Flexible piezoresistive
sensor with the microarray structure
International Journal of Chemical Engineering and Materials
DOI: 10.37394/232031.2024.3.1
K. Saujanya, B. Poornaiah,
A. Kamala Kumari, Y. Srinivasa Rao
E-ISSN: 2945-0519
7
Volume 3, 2024
based on self-assembly of multi-walled
carbon nanotubes,” Sensors
(Switzerland), vol. 19, no. 22, 2019, doi:
10.3390/s19224985.
[32] Z. Tian, Y. Li, S. Li, S. Vute, and J. Ji,
“Influence of particle morphology and
concentration on the piezoresistivity of
cement-based sensors with magneto-
aligned nickel fillers,” Meas. J. Int.
Meas. Confed., vol. 187, no. October
2021, p. 110194, 2022, doi:
10.1016/j.measurement.2021.110194.
[33] Daniel Zymelka et al., “Large-scale
printed strain sensors based on carbon
ink incorporated into an intermittent
conductive silver pattern” 2021 Jpn. J.
Appl. Phys. 60 SBBM01, DOI
10.35848/1347-4065/abd6db
[34] A. Arivarasi, R. Anand Kumar, “3D
Printing of Copper Filament for Layered
Fabrication” Volume 7, 2016, WSEAS
TRANSACTIONS on ELECTRONICS.
E-ISSN: 2415-1513
[35] M. J. Burke, C. Molloy, H. Fossan,
“Low-Power Measurement of Contact
Impedance in Dry Electrocardiography”
Volume 7, 2016, WSEAS
TRANSACTIONS on ELECTRONICS.
E-ISSN: 2415-1513
Contribution of Individual Authors to the
Creation of a Scientific Article (Ghostwriting
Policy)
The authors equally contributed in the present
research, at all stages from the formulation of the
problem to the final findings and solution.
Sources of Funding for Research Presented in a
Scientific Article or Scientific Article Itself
No funding was received for conducting this study.
Conflict of Interest
The authors have no conflicts of interest to declare
that are relevant to the content of this article.
Creative Commons Attribution License 4.0
(Attribution 4.0 International, CC BY 4.0)
This article is published under the terms of the
Creative Commons Attribution License 4.0
https://creativecommons.org/licenses/by/4.0/deed.en
_US
International Journal of Chemical Engineering and Materials
DOI: 10.37394/232031.2024.3.1
K. Saujanya, B. Poornaiah,
A. Kamala Kumari, Y. Srinivasa Rao
E-ISSN: 2945-0519
8
Volume 3, 2024