Robust Surface-Engineered Tape-Cast and Extrusion Methods to Fabricate Electrically-Conductive Poly(vinylidene fluoride)/Carbon Nanotube Filaments for Corrosion-Resistant 3D Printing Applications

Asma Almazrouei; Rahmat Agung Susantyoko; Chieh-Han Wu; Ibrahim Mustafa; Ayoob Alhammadi; Saif Almheiri

doi:10.1038/s41598-019-45992-5

Robust Surface-Engineered Tape-Cast and Extrusion Methods to Fabricate Electrically-Conductive Poly(vinylidene fluoride)/Carbon Nanotube Filaments for Corrosion-Resistant 3D Printing Applications

Sci Rep. 2019 Jul 3;9(1):9618. doi: 10.1038/s41598-019-45992-5.

Authors

Asma Almazrouei¹, Rahmat Agung Susantyoko², Chieh-Han Wu³, Ibrahim Mustafa³, Ayoob Alhammadi³, Saif Almheiri^{4

5}

Affiliations

¹ Engineering Systems and Management, Khalifa University of Science and Technology, Masdar Institute, Masdar City, P.O. Box 54224, Abu Dhabi, United Arab Emirates.
² Department of Mechanical Engineering, Khalifa University of Science and Technology, Masdar Institute, Masdar City, P.O. Box 54224, Abu Dhabi, United Arab Emirates. rahmat.a.susantyoko@alum.mit.edu.
³ Department of Mechanical Engineering, Khalifa University of Science and Technology, Masdar Institute, Masdar City, P.O. Box 54224, Abu Dhabi, United Arab Emirates.
⁴ Department of Mechanical Engineering, Khalifa University of Science and Technology, Masdar Institute, Masdar City, P.O. Box 54224, Abu Dhabi, United Arab Emirates. contact@saifalmheiri.com.
⁵ Mohammed bin Rashid Al Maktoum Solar Park, Dubai Electricity & Water Authority (DEWA), Dubai, United Arab Emirates. contact@saifalmheiri.com.

Abstract

We developed a poly(vinylidene fluoride)/carbon nanotube (PVDF-MWCNT) filament as a feed for printing of electrically-conductive and corrosion-resistant functional material by fused filament fabrication (FFF). Using an environment-friendly procedure to fabricate PVDF-MWCNT filament, we achieved the best reported electrical conductivity of printable PVDF-MWCNT filament of 28.5 S cm^-1 (90 wt% PVDF and 10 wt% CNT). The PVDF-MWCNT filaments are chemically stable in acid, base, and salt solution, with no significant changes in electrical conductivity and mass of the filaments. Our processing method is robust and allow a uniform mixture of PVDF and CNT with a wide range of CNT percentage up to 99.9%. We demonstrated the printing of PVDF-MWCNT filaments to create 3D shapes; printed using a low-cost commercial consumer-grade FFF 3D printer. We found many adjustments of printer parameters are needed to print filament with CNT content >10 wt%, but easier printing for CNT content ≤10 wt%. Since this was due to printer limitation, we believed that PVDF-MWCNT with higher CNT percentage (to a certain limit) and larger electrical conductivity could be printed with a custom-built printer (for example stronger motor). PVDF-MWCNT filament shows higher electrical conductivity (28.5 S cm^-1) than compressed composite (8.8 S cm^-1) of the same 10 wt% of CNT, due to more alignment of CNT in the longitudinal direction of the extruded filament. Printable PVDF-MWCNT-Fe₂O₃ (with a functional additive of Fe₂O₃) showed higher electrical conductivity in the longitudinal direction at the filament core (42 S cm^-1) compared to that in the longitudinal direction at the filament shell (0.43 S cm^-1) for sample with composition of 60 wt% PVDF, 20 wt% CNT, and 20 wt% Fe₂O₃, due to extrusion skin effect with segregation of electrically insulating Fe₂O₃ at the shell surface of PVDF-MWCNT-Fe₂O₃.