Microstructured MWCNT/PDMS Composites for Multiple Sensing Applications

Abstract

first_page settings Order Article Reprints Font Type: Arial Georgia Verdana Font Size: Aa Aa Aa Line Spacing:    Column Width:    Background: Open AccessAbstract Microstructured MWCNT/PDMS Composites for Multiple Sensing Applications † by Cláudia S. Buga 1,2 and Júlio C. Viana 1,2,* 1 IPC/LASI—Institute for Polymers and Composites, Associated Laboratory in Intelligent Systems, University of Minho, Campus de Azurém, 4800-058 Guimarães, Portugal 2 DTx Colab—Digital Transformation, University of Minho, Campus de Azurém, 4800-058 Guimarães, Portugal * Author to whom correspondence should be addressed. † Presented at the Materiais 2022, Marinha Grande, Portugal, 10–13 April 2022. Mater. Proc. 2022, 8(1), 54; https://doi.org/10.3390/materproc2022008054 Published: 31 May 2022 (This article belongs to the Proceedings of MATERIAIS 2022) Download Download PDF Download XML Versions Notes With the growing interest in flexible, lightweight, sustainable, and cost-efficient electronics, innovative and replicable manufacturing solutions are in demand. Pure silicon is still the most used semiconductive material in electronics. However, to address issues related to its processing, sustainability, and lack of flexibility, new materials are being developed. As a result, semiconductive alternatives based upon carbon allotropes, carbon-based composites, and electrically conductive polymers have emerged. Unfortunately, most of them are still difficult to process and lack reproducibility and their performances are not capable of competing with those of the traditionally used materials. To contradict the abovementioned tendency, a new formulation is proposed herein to produce piezoresistive MWCNT/PDMS composites with versatile and tunable electric properties. The developed composite is obtained rapidly through fewer manufacturing steps and avoiding the use of hazardous solvents. To discover the percolation threshold of the composite, the MWCNT were first dispersed in IPA using an ultrasonic probe and then mixed with the PDMS pre-polymer in different weight percentages, ranging from 0.3 wt% to 8.0 wt%. Results evidenced that by using 3 wt% of MWCNT in PDMS, highly sensitive pressure sensors could be achieved. To further enhance the dispersion of the MWCNT and add microstructure to the composite, Triton X-100 (1 wt%) was used as a surfactant and sodium bicarbonate (10 wt%) as the foaming agent. By adding these substances during the dispersion process, not only were the piezoresistive properties of the composites enhanced but it was possible to obtain porous structures with interconnected pores, which improved the sensing range of the final material. To produce the sensing units, the composite was blade coated and integrated with screen-printed silver interdigital electrodes. The resulting sensors presented a fast response rate, low hysteresis, high reliability, repeatability, and a sensing range of 0.5 kPa–70 kPa, with good linearity between 0.5 kPa and 15 kPa and resolution of 0.5 kPa. Thanks to the high sensitivity of the developed sensors, they have the potential to be used in applications such as prosthetics, soft grippers, electronic skins, and biomonitoring devices. As proof of concept, a heartbeat sensor and a pressure sensing matrix are presented in this work, thus illustrating the potential and versatility of MWCNT/PDMS composites for future flexible, conformable, and connected applications. Author ContributionsConceptualization, J.C.V. and C.S.B.; methodology, J.C.V. and C.S.B.; software, J.C.V. and C.S.B.; validation, J.C.V. and C.S.B.; formal analysis, J.C.V. and C.S.B.; investigation, J.C.V. and C.S.B.; resources, J.C.V. and C.S.B.; data curation, C.S.B.; writing—original draft preparation, C.S.B.; writing—review and editing, J.C.V. and C.S.B.; visualization, J.C.V. and C.S.B.; supervision, J.C.V.; project administration, J.C.V.; funding acquisition, J.C.V. All authors have read and agreed to the published version of the manuscript.FundingThis work has been supported by NORTE-06-3559-FSE-000018, integrated in the invitation NORTE-59-2018-41, aiming the Hiring of Highly Qualified Human Resources, co-financed by the Regional Operational Programme of the North 2020, thematic area of Competitiveness and Employment, through the European Social Fund (ESF), and by the scope of projects with references UIDB/05256/2020 and UIDP/05256/2020, financed by FCT—Fundação para a Ciência e Tecnologia, Portugal.Conflicts of InterestThe authors declare no conflict of interest.Publisher's Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/). Share and Cite MDPI and ACS Style Buga, C.S.; Viana, J.C. Microstructured MWCNT/PDMS Composites for Multiple Sensing Applications. Mater. Proc. 2022, 8, 54. https://doi.org/10.3390/materproc2022008054 AMA Style Buga CS, Viana JC. Microstructured MWCNT/PDMS Composites for Multiple Sensing Applications. Materials Proceedings. 2022; 8(1):54. https://doi.org/10.3390/materproc2022008054 Chicago/Turabian Style Buga, Cláudia S., and Júlio C. Viana. 2022. "Microstructured MWCNT/PDMS Composites for Multiple Sensing Applications" Materials Proceedings 8, no. 1: 54. https://doi.org/10.3390/materproc2022008054 Find Other Styles Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here. Article Metrics No No Article Access Statistics Multiple requests from the same IP address are counted as one view.