Development of MWCNT/Magnetite Flexible Triboelectric Sensors by Magnetic Patterning
The fabrication of low-electrical-percolation-threshold polymer composites aims to reduce the weight fraction of the conductive nanomaterial necessary to achieve a given level of electrical resistivity of the composite. The present work aimed at preparing composites based on multiwalled carbon nanot...
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| Format: | Article |
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MDPI AG
2023-06-01
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| Series: | Polymers |
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| Online Access: | https://www.mdpi.com/2073-4360/15/13/2870 |
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| author | David Seixas Esteves Manuel F. C. Pereira Ana Ribeiro Nelson Durães Maria C. Paiva Elsa W. Sequeiros |
| author_facet | David Seixas Esteves Manuel F. C. Pereira Ana Ribeiro Nelson Durães Maria C. Paiva Elsa W. Sequeiros |
| author_sort | David Seixas Esteves |
| collection | DOAJ |
| description | The fabrication of low-electrical-percolation-threshold polymer composites aims to reduce the weight fraction of the conductive nanomaterial necessary to achieve a given level of electrical resistivity of the composite. The present work aimed at preparing composites based on multiwalled carbon nanotubes (MWCNTs) and magnetite particles in a polyurethane (PU) matrix to study the effect on the electrical resistance of electrodes produced under magnetic fields. Composites with 1 wt.% of MWCNT, 1 wt.% of magnetite and combinations of both were prepared and analysed. The hybrid composites combined MWCNTs and magnetite at the weight ratios of 1:1; 1:1/6; 1:1/12; and 1:1/24. The results showed that MWCNTs were responsible for the electrical conductivity of the composites since the composites with 1 wt.% magnetite were non-conductive. Combining magnetite particles with MWCNTs reduces the electrical resistance of the composite. SQUID analysis showed that MWCNTs simultaneously exhibit ferromagnetism and diamagnetism, ferromagnetism being dominant at lower magnetic fields and diamagnetism being dominant at higher fields. Conversely, magnetite particles present a ferromagnetic response much stronger than MWCNTs. Finally, optical microscopy (OM) and X-ray micro computed tomography (micro CT) identified the interaction between particles and their location inside the composite. In conclusion, the combination of magnetite and MWCNTs in a polymer composite allows for the control of the location of these particles using an external magnetic field, decreasing the electrical resistance of the electrodes produced. By adding 1 wt.% of magnetite to 1 wt.% of MWCNT (1:1), the electric resistance of the composites decreased from 9 × 10<sup>4</sup> to 5 × 10<sup>3</sup> Ω. This approach significantly improved the reproducibility of the electrode’s fabrication process, enabling the development of a triboelectric sensor using a polyurethane (PU) composite and silicone rubber (SR). Finally, the method’s bearing was demonstrated by developing an automated robotic soft grip with tendon-driven actuation controlled by the triboelectric sensor. The results indicate that magnetic patterning is a versatile and low-cost approach to manufacturing sensors for soft robotics. |
| first_indexed | 2024-03-11T01:30:58Z |
| format | Article |
| id | doaj.art-0bb97f735ae44f57a681a0426ee466cb |
| institution | Directory Open Access Journal |
| issn | 2073-4360 |
| language | English |
| last_indexed | 2024-03-11T01:30:58Z |
| publishDate | 2023-06-01 |
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| record_format | Article |
| series | Polymers |
| spelling | doaj.art-0bb97f735ae44f57a681a0426ee466cb2023-11-18T17:21:20ZengMDPI AGPolymers2073-43602023-06-011513287010.3390/polym15132870Development of MWCNT/Magnetite Flexible Triboelectric Sensors by Magnetic PatterningDavid Seixas Esteves0Manuel F. C. Pereira1Ana Ribeiro2Nelson Durães3Maria C. Paiva4Elsa W. Sequeiros5Department of Metallurgical and Materials Engineering, Faculty of Engineering, University of Porto, 4200-465 Porto, PortugalCERENA, Center for Natural Resources and Environment, IST, University of Lisbon, 1049-001 Lisboa, PortugalCENTI, Centre for Nanotechnology and Smart Materials, 4760-034 Vila Nova de Famalicão, PortugalCENTI, Centre for Nanotechnology and Smart Materials, 4760-034 Vila Nova de Famalicão, PortugalDepartment of Polymer Engineering, Institute for Polymers and Composites, University of Minho, 4800-058 Guimarães, PortugalDepartment of Metallurgical and Materials Engineering, Faculty of Engineering, University of Porto, 4200-465 Porto, PortugalThe fabrication of low-electrical-percolation-threshold polymer composites aims to reduce the weight fraction of the conductive nanomaterial necessary to achieve a given level of electrical resistivity of the composite. The present work aimed at preparing composites based on multiwalled carbon nanotubes (MWCNTs) and magnetite particles in a polyurethane (PU) matrix to study the effect on the electrical resistance of electrodes produced under magnetic fields. Composites with 1 wt.% of MWCNT, 1 wt.% of magnetite and combinations of both were prepared and analysed. The hybrid composites combined MWCNTs and magnetite at the weight ratios of 1:1; 1:1/6; 1:1/12; and 1:1/24. The results showed that MWCNTs were responsible for the electrical conductivity of the composites since the composites with 1 wt.% magnetite were non-conductive. Combining magnetite particles with MWCNTs reduces the electrical resistance of the composite. SQUID analysis showed that MWCNTs simultaneously exhibit ferromagnetism and diamagnetism, ferromagnetism being dominant at lower magnetic fields and diamagnetism being dominant at higher fields. Conversely, magnetite particles present a ferromagnetic response much stronger than MWCNTs. Finally, optical microscopy (OM) and X-ray micro computed tomography (micro CT) identified the interaction between particles and their location inside the composite. In conclusion, the combination of magnetite and MWCNTs in a polymer composite allows for the control of the location of these particles using an external magnetic field, decreasing the electrical resistance of the electrodes produced. By adding 1 wt.% of magnetite to 1 wt.% of MWCNT (1:1), the electric resistance of the composites decreased from 9 × 10<sup>4</sup> to 5 × 10<sup>3</sup> Ω. This approach significantly improved the reproducibility of the electrode’s fabrication process, enabling the development of a triboelectric sensor using a polyurethane (PU) composite and silicone rubber (SR). Finally, the method’s bearing was demonstrated by developing an automated robotic soft grip with tendon-driven actuation controlled by the triboelectric sensor. The results indicate that magnetic patterning is a versatile and low-cost approach to manufacturing sensors for soft robotics.https://www.mdpi.com/2073-4360/15/13/2870MWCNTferromagneticflexible and stretchable sensorssmart compositessensor fabricationpolymer composites |
| spellingShingle | David Seixas Esteves Manuel F. C. Pereira Ana Ribeiro Nelson Durães Maria C. Paiva Elsa W. Sequeiros Development of MWCNT/Magnetite Flexible Triboelectric Sensors by Magnetic Patterning Polymers MWCNT ferromagnetic flexible and stretchable sensors smart composites sensor fabrication polymer composites |
| title | Development of MWCNT/Magnetite Flexible Triboelectric Sensors by Magnetic Patterning |
| title_full | Development of MWCNT/Magnetite Flexible Triboelectric Sensors by Magnetic Patterning |
| title_fullStr | Development of MWCNT/Magnetite Flexible Triboelectric Sensors by Magnetic Patterning |
| title_full_unstemmed | Development of MWCNT/Magnetite Flexible Triboelectric Sensors by Magnetic Patterning |
| title_short | Development of MWCNT/Magnetite Flexible Triboelectric Sensors by Magnetic Patterning |
| title_sort | development of mwcnt magnetite flexible triboelectric sensors by magnetic patterning |
| topic | MWCNT ferromagnetic flexible and stretchable sensors smart composites sensor fabrication polymer composites |
| url | https://www.mdpi.com/2073-4360/15/13/2870 |
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