Piezoresistive anisotropy in conductive silicon rubber/multi-walled carbon nanotube/nickel particle composites via alignment of nickel particles

• Published in: Composites science and technology Vol. 225; p. 109520
• Main Authors: Chen, Yi-Fu, Huang, Ming-Lu, Cai, Jie-Hua, Weng, Yun-Xuan, Wang, Ming
• Format: Journal Article
• Language: English
• Published: Barking Elsevier Ltd 07.07.2022; Elsevier BV
• Subjects: Alignment; Anisotropy; Conducting polymers; Electrical resistivity; Flux density; Heat conductivity; Magnetic fields; Magnetic flux; Multi wall carbon nanotubes; Multi-walled carbon nanotube; Nanotubes; Nickel; Nickel particles; Particulate composites; Piezoresistive anisotropy; Polydimethylsiloxane; Polymer matrix composites; Polymers; Rubber; Silicon; Alignment; Multi-walled carbon nanotube; Polydimethylsiloxane; Nickel particles; Piezoresistive anisotropy
• ISSN: 0266-3538; 1879-1050
• DOI: 10.1016/j.compscitech.2022.109520

Conventional piezoresistive sensors of flexible conductive polymer composites (FCPC) are mostly isotropic because of the weak controllable fabrication strategies. In this study, a facile strategy was introduced to fabricate the polydimethylsiloxane (PDMS)/multi-walled carbon nanotubes (CNT)/aligned nickel particles (Ni) composites under a low magnetic field. The PDMS pre-polymer firstly mixed with CNT and Ni particles with ultrasonic and solvent assistant, and then cured under a magnetic field with a magnetic flux density of 75 mT to form the composites. Because of the alignment of Ni particles, the PDMS/CNT/align-Ni composites exhibited obviously electrical, mechanical and piezoresistive anisotropy. Specifically, the compression modulus of the composites with 0.23 vol% CNTs and 3.93 vol% Ni particles was ∼4.93 and ∼3.66 MPa at the direction parallel to (X direction) and vertical to the alignment direction of Ni particles (Y direction), respectively. The anisotropic index of the electrical conductivity could reach 2.6 × 105 in the PDMS/CNT/aligned-Ni composites containing 0.23 vol% CNT and 3.37 vol% Ni particles. Furthermore, the PDMS/CNT/aligned-Ni composites showed a negative piezoresistive effect at X direction and a positive piezoresistive effect at Y direction. [Display omitted] •Piezoresistive anisotropy was achieved by aligning Ni particles in the composites.•Modulus anisotropy was found in the composites with Ni alignment.•Anisotropic index of electrical conductivity reach 2.6 × 105 in the aligned samples.•Negative piezoresistive effect was found along the aligned direction.•Positive piezoresistive effect existed at the direction vertical to Ni “chains”.