Healable and Foldable Carbon Nanotube/Wax Conductive Composite

Abstract

In this study, a composite material with healable and foldable features is formulated to print conductive patterns on rough surfaces, such as paper, cloth, and three-dimensional (3D) printed objects. Carbon nanotubes (CNTs) are mixed with wax to formulate a solid composite for pen writing. The composite has a low percolation threshold of 2.5 wt % CNTs and can be written on various rough substrates, such as paper and cloth, to create conductive patterns for electronic conductors. Because of the strong infrared (IR) absorption of CNTs, the printed patterns can be selectively sintered by noncontact IR radiation efficiently to show great electrical conductivity. The electrical resistance of the written patterns on paper also show an insignificant increase after bending, folding, and crumpling. Furthermore, the conductive composite exhibits great healability after destructive damages. The conductivity of the damaged patterns after severe folding or knife cutting recovers to its original value with thermal or IR heating. Several examples, such as conductive tracks on paper, cloth, or 3D printed objects, are also demonstrated to show the potential of this healable conductive composite for electronic applications.

Highly conductive carbon-based aqueous inks toward electroluminescent devices, printed capacitive sensors and flexible wearable electronics

“…[1][2][3][4][5] Because of their exceptional chemical, mechanical, electrical, and optical properties, they can greatly improve the performance of conductive inks. [6][7][8][9][10] Graphite is a laminar structure with several tens of microns long. Carbon black (CB) is a submicron-sized conductive sphere with larger specic surface area than graphite.…”

“…Ferdinand Hof et al 22 dispersed the prepared graphitic nanoparticles in water and obtained the conductive ink with sheet resistance as low as 220 U sq À1 on normalised thickness of 25 mm. Tso-Hsuan Chen et al 10 mixed carbon nanotubes (CNTs) with wax to formulate a solid composite for pen writing with the sheet resistance of 200 U sq À1 on a thickness of 90 mm. In fact, the resistance of these carbon conductive inks synthesized by the above methods are relatively large, and are not suitable for printed electronic products.…”

“…A series of comparative experiments were conducted to obtain a formula. Tenfold of the conductivity has been improved by adding the right amount of MWNT-f-OH which's an extended study of Chris Phillips et al 10,12,21,22 These inks could be applied to most printing techniques such as screen printing, exography, or gravure printing. We also demonstrate the preparation of a large-sized (900 cm 2 ) EL device with a power of 4.0 mW cm À2 using the conductive ink instead of silver paste as the back electrode, which's never reported in previous studies.…”

Sustainable Macromolecular Materials in Flexible Electronics

“…In 2018, Chen et al published their promising study on healable and foldable conductive composites made with beeswax-based carbon nanotubes. [280] MWCNTs were doped into beeswax with an affordable wet chemistry procedure, and this conductive mixture was molded as a pen with different weight fractions. Conductive patterns were drawn on cellulose paper and 3D-printed PLA objects.…”

Advances in the Development of Liquid Metal-Based Printed Electronic Inks

“…A graphene circuit is thus fabricated on the paper substrate through such transfer printing approach. To further improve the properties of carbon material, carbon-based composites such as graphene-silver ink (Karim et al, 2019), carbon nanotube/wax conductive ink (Chen et al, 2018), carbon nanotube/liquid metal ink (Park et al, 2019), and so on have also been tried for electronic applications.…”