Fabrication and Evaluation of Polydimethylsiloxane-La<sub>2</sub>O<sub>3</sub> Composites-Based Flexible Capacitance Pressure Sensors&#x2019; Parameters and Applications

Flexible capacitance pressure sensors (fCPS) with high sensitivity, wide linear working range, fast response and recovery times, low hysteresis, and long durability with stable output are very much needed for many physical sensor applications. For flexibility sensors both capacitor plates and dielec...

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Main Authors: Soly Mathew, Krishnamoorthi Chintagumpala
Format: Article
Language:English
Published: IEEE 2025-01-01
Series:IEEE Access
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Online Access:https://ieeexplore.ieee.org/document/11025544/
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author Soly Mathew
Krishnamoorthi Chintagumpala
author_facet Soly Mathew
Krishnamoorthi Chintagumpala
author_sort Soly Mathew
collection DOAJ
description Flexible capacitance pressure sensors (fCPS) with high sensitivity, wide linear working range, fast response and recovery times, low hysteresis, and long durability with stable output are very much needed for many physical sensor applications. For flexibility sensors both capacitor plates and dielectric sandwich layer in parallel plate capacitor (PPC) geometry should be flexible with low elastic modulus (E) with high tensile break point. For this purpose, many researchers were used flexible polymer sheet with surface conductive material coating as a flexible capacitor electrodes, and elastomer composites as dielectric sandwich layers. Capacitance (C) of a PPC sensor is C=<inline-formula> <tex-math notation="LaTeX">$\epsilon \frac {A}{D}$ </tex-math></inline-formula>, here <inline-formula> <tex-math notation="LaTeX">$\epsilon $ </tex-math></inline-formula> is dielectric permittivity of sandwich layer, A is effective area of PPC electrode plates, and D is distance between the electrode plates. Here change in capacitance under applied pressure is induced by change in <inline-formula> <tex-math notation="LaTeX">$\epsilon $ </tex-math></inline-formula> as well as D. Flexible dielectric elastomer composites (DECs) with high dielectric constant (<inline-formula> <tex-math notation="LaTeX">$\epsilon _{\text {r}}$ </tex-math></inline-formula>) were prepared by adding 0, 0.45, 0.90, &#x0026; 1.34 mass% of relatively high dielectric La2O3 ceramic nanoparticles as fillers to polydimethylsiloxane (PDMS) matrix. The DEC were spin coated to make 0.2 mm thick films to use in PPCs. Four fCPS were fabricated using conductive silver epoxy coated polyethylene terephthalate (PET) substrates (0.125 mm thickness) for PPC electrodes and 0.2 mm thick DECs as sandwich layers. Sensitivity of the fCPS increases with La2O3 filler content. Among the four fCPS studied here, fCPS with 1.34 mass% La2O3 DEC shows highest sensitivity of 23.77 pF/kPa, linear working range in 0&#x2013;2.56 kPa, response and recovery times of 123 &#x0026; 126 ms, negligible hysteresis in 0-128 kPa range, and long durability with stable output. Compressive and tensile strain sensing capabilities of this sensor was tested in the real time applications.
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spelling doaj-art-3a9cfdaa737d458c817425d57b7ed2ec2025-08-20T02:32:42ZengIEEEIEEE Access2169-35362025-01-0113993439935410.1109/ACCESS.2025.357706611025544Fabrication and Evaluation of Polydimethylsiloxane-La<sub>2</sub>O<sub>3</sub> Composites-Based Flexible Capacitance Pressure Sensors&#x2019; Parameters and ApplicationsSoly Mathew0https://orcid.org/0009-0001-2480-4682Krishnamoorthi Chintagumpala1https://orcid.org/0000-0003-0786-8454Center for Nanotechnology Research, Vellore Institute of Technology, Vellore, Tamil Nadu, IndiaCenter for Nanotechnology Research, Vellore Institute of Technology, Vellore, Tamil Nadu, IndiaFlexible capacitance pressure sensors (fCPS) with high sensitivity, wide linear working range, fast response and recovery times, low hysteresis, and long durability with stable output are very much needed for many physical sensor applications. For flexibility sensors both capacitor plates and dielectric sandwich layer in parallel plate capacitor (PPC) geometry should be flexible with low elastic modulus (E) with high tensile break point. For this purpose, many researchers were used flexible polymer sheet with surface conductive material coating as a flexible capacitor electrodes, and elastomer composites as dielectric sandwich layers. Capacitance (C) of a PPC sensor is C=<inline-formula> <tex-math notation="LaTeX">$\epsilon \frac {A}{D}$ </tex-math></inline-formula>, here <inline-formula> <tex-math notation="LaTeX">$\epsilon $ </tex-math></inline-formula> is dielectric permittivity of sandwich layer, A is effective area of PPC electrode plates, and D is distance between the electrode plates. Here change in capacitance under applied pressure is induced by change in <inline-formula> <tex-math notation="LaTeX">$\epsilon $ </tex-math></inline-formula> as well as D. Flexible dielectric elastomer composites (DECs) with high dielectric constant (<inline-formula> <tex-math notation="LaTeX">$\epsilon _{\text {r}}$ </tex-math></inline-formula>) were prepared by adding 0, 0.45, 0.90, &#x0026; 1.34 mass% of relatively high dielectric La2O3 ceramic nanoparticles as fillers to polydimethylsiloxane (PDMS) matrix. The DEC were spin coated to make 0.2 mm thick films to use in PPCs. Four fCPS were fabricated using conductive silver epoxy coated polyethylene terephthalate (PET) substrates (0.125 mm thickness) for PPC electrodes and 0.2 mm thick DECs as sandwich layers. Sensitivity of the fCPS increases with La2O3 filler content. Among the four fCPS studied here, fCPS with 1.34 mass% La2O3 DEC shows highest sensitivity of 23.77 pF/kPa, linear working range in 0&#x2013;2.56 kPa, response and recovery times of 123 &#x0026; 126 ms, negligible hysteresis in 0-128 kPa range, and long durability with stable output. Compressive and tensile strain sensing capabilities of this sensor was tested in the real time applications.https://ieeexplore.ieee.org/document/11025544/Dielectric elastomer compositesflexible piezocapacitance sensorLa2O3 nanoparticlespressure sensor
spellingShingle Soly Mathew
Krishnamoorthi Chintagumpala
Fabrication and Evaluation of Polydimethylsiloxane-La<sub>2</sub>O<sub>3</sub> Composites-Based Flexible Capacitance Pressure Sensors&#x2019; Parameters and Applications
IEEE Access
Dielectric elastomer composites
flexible piezocapacitance sensor
La2O3 nanoparticles
pressure sensor
title Fabrication and Evaluation of Polydimethylsiloxane-La<sub>2</sub>O<sub>3</sub> Composites-Based Flexible Capacitance Pressure Sensors&#x2019; Parameters and Applications
title_full Fabrication and Evaluation of Polydimethylsiloxane-La<sub>2</sub>O<sub>3</sub> Composites-Based Flexible Capacitance Pressure Sensors&#x2019; Parameters and Applications
title_fullStr Fabrication and Evaluation of Polydimethylsiloxane-La<sub>2</sub>O<sub>3</sub> Composites-Based Flexible Capacitance Pressure Sensors&#x2019; Parameters and Applications
title_full_unstemmed Fabrication and Evaluation of Polydimethylsiloxane-La<sub>2</sub>O<sub>3</sub> Composites-Based Flexible Capacitance Pressure Sensors&#x2019; Parameters and Applications
title_short Fabrication and Evaluation of Polydimethylsiloxane-La<sub>2</sub>O<sub>3</sub> Composites-Based Flexible Capacitance Pressure Sensors&#x2019; Parameters and Applications
title_sort fabrication and evaluation of polydimethylsiloxane la sub 2 sub o sub 3 sub composites based flexible capacitance pressure sensors x2019 parameters and applications
topic Dielectric elastomer composites
flexible piezocapacitance sensor
La2O3 nanoparticles
pressure sensor
url https://ieeexplore.ieee.org/document/11025544/
work_keys_str_mv AT solymathew fabricationandevaluationofpolydimethylsiloxanelasub2subosub3subcompositesbasedflexiblecapacitancepressuresensorsx2019parametersandapplications
AT krishnamoorthichintagumpala fabricationandevaluationofpolydimethylsiloxanelasub2subosub3subcompositesbasedflexiblecapacitancepressuresensorsx2019parametersandapplications