Highly Sensitive Flexible Pressure Sensors Enabled by Mixing of Silicone Elastomer With Ionic Liquid-Grafted Silicone Oil
Open Access
- 20 September 2021
- journal article
- research article
- Published by Frontiers Media SA in Frontiers in Robotics and AI
Abstract
Developing highly sensitive flexible pressure sensors has become crucially urgent due to the increased societal demand for wearable electronic devices capable of monitoring various human motions. The sensitivity of such sensors has been shown to be significantly enhanced by increasing the relative dielectric permittivity of the dielectric layers used in device construction via compositing with immiscible ionic conductors. Unfortunately, however, the elastomers employed for this purpose possess inhomogeneous morphologies, and thus suffer from poor long-term durability and unstable electrical response. In this study, we developed a novel, flexible, and highly sensitive pressure sensor using an elastomeric dielectric layer with particularly high permittivity and homogeneity due to the addition of synthesized ionic liquid-grafted silicone oil (denoted LMS-EIL). LMS-EIL possesses both a very high relative dielectric permittivity (9.6 × 105 at 10−1 Hz) and excellent compatibility with silicone elastomers due to the covalently connected structure of conductive ionic liquid (IL) and chloropropyl silicone oil. A silicone elastomer with a relative permittivity of 22 at 10−1 Hz, Young’s modulus of 0.78 MPa, and excellent homogeneity was prepared by incorporating 10 phr (parts per hundreds rubber) of LMS-EIL into an elastomer matrix. The sensitivity of the pressure sensor produced using this optimized silicone elastomer was 0.51 kPa−1, which is 100 times higher than that of the pristine elastomer. In addition, a high durability illustrated by 100 loading–unloading cycles and a rapid response and recovery time of approximately 60 ms were achieved. The excellent performance of this novel pressure sensor suggests significant potential for use in human interfaces, soft robotics, and electronic skin applications.This publication has 45 references indexed in Scilit:
- Ultrafast Dynamic Piezoresistive Response of Graphene‐Based Cellular ElastomersAdvanced Materials, 2015
- Silicone rubbers for dielectric elastomers with improved dielectric and mechanical properties as a result of substituting silica with titanium dioxideInternational Journal of Smart and Nano Materials, 2015
- A new soft dielectric silicone elastomer matrix with high mechanical integrity and low lossesRSC Advances, 2015
- Stiffening solids with liquid inclusionsNature Physics, 2014
- Advances of flexible pressure sensors toward artificial intelligence and health care applicationsMater. Horiz., 2014
- Ultrasensitive Piezoresistive All‐Organic Flexible Thin FilmsAdvanced Materials, 2010
- Protic Ionic Liquids with Unusually High Dielectric PermittivitiesChemphyschem, 2008
- Imidazolium-based alkylphosphate ionic liquids – A potential solvent for extractive desulfurization of fuelFuel, 2008
- The Dielectric Response of Room-Temperature Ionic Liquids: Effect of Cation VariationThe Journal of Physical Chemistry B, 2007
- Significantly Enhanced Reactivities of the Nucleophilic Substitution Reactions in Ionic LiquidThe Journal of Organic Chemistry, 2003