Synthesis and characterization of carbon nanotube-doped thermoplastic nanocomposites for the additive manufacturing of self-sensing piezoresistive materials

Verma, P., Ubaid, J., Varadarajan, K. M., Wardle, B. L. and Kumar, S. (2022) Synthesis and characterization of carbon nanotube-doped thermoplastic nanocomposites for the additive manufacturing of self-sensing piezoresistive materials. ACS Applied Materials and Interfaces, 14(6), pp. 8361-8372. (doi: 10.1021/acsami.1c20491) (PMID:35119271)

Abstract

We present carbon nanotube (CNT)-reinforced polypropylene random copolymer (PPR) nanocomposites for the additive manufacturing of self-sensing piezoresistive materials via fused filament fabrication. The PPR/CNT feedstock filaments were synthesized through high shear-induced melt blending with controlled CNT loading up to 8 wt % to enable three-dimensional (3D) printing of nanoengineered PPR/CNT composites. The CNTs were found to enhance crystallinity (up to 6%) in PPR-printed parts, contributing to the overall CNT-reinforcement effect that increases both stiffness and strength (increases of 56% in modulus and 40% in strength at 8 wt % CNT loading). Due to electrical conductivity (∼10–4–10–1 S/cm with CNT loading) imparted to the PPR by the CNT network, multifunctional in situ strain and damage sensing in 3D-printed CNT/PPR bulk composites and lattice structures are revealed. A useful range of gauge factors (k) is identified for strain sensing (ks = 10.1–17.4) and damage sensing (kd = 20–410) across the range of CNT loadings for the 0° print direction. Novel auxetic re-entrant and S-unit cell lattices are printed, with multifunctionality demonstrated as strain- and damage-sensing in tension. The PPR/CNT multifunctional nanocomposite lattices demonstrated here exhibit tunable strain and damage sensitivity and have application in biomedical engineering for the creation of self-sensing patient-specific devices such as orthopedic braces, where the ability to sense strain (and stress) can provide direct information for optimization of brace design/fit over the course of treatment.

• Item Type: Articles
• Additional Information: The authors gratefully acknowledge financial support from the ADNOC under Award No. EX2016-000010.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Kumar, Professor Shanmugam
• Authors: Verma, P., Ubaid, J., Varadarajan, K. M., Wardle, B. L., and Kumar, S.
• College/School: College of Science and Engineering > School of Engineering > Systems Power and Energy
• Journal Name: ACS Applied Materials and Interfaces
• Publisher: American Chemical Society
• ISSN: 1944-8244
• ISSN (Online): 1944-8252
• Published Online: 04 February 2022
• Copyright Holders: Copyright © 2022 American Chemical Society
• First Published: First published in ACS Applied Materials and Interfaces 14(6):8361-8372
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher

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