Soft, conductive nanocomposites based on ionic liquids/carbon nanotubes for 3D printing of flexible electronic devices

Abstract

In this work, we present the preparation, characterization, and 3D printing of highly conductive, soft, and functional nanocomposite polymers. The prepared nanocomposite is a polymeric system that consists of poly (ionic liquid) (PIL), polymethylmethacrylate (PMMA), and multiwalled carbon nanotubes (MWCNTs) as fillers and an ionic liquid (IL) that acts as a plasticizer and dopant for the MWCNTs. The nanocomposites exhibited variable mechanical (strain at break: 50–250%) and conductive properties depending on their composition, and the highest conductivity of 520 Sm−1 was attained with 15 wt.% MWCNT loading owing to the well-defined morphology of the MWCNTs revealed by SEM. The thermal properties of the nanocomposites were measured by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). The results revealed high thermal stability up to 340 °C regardless of the composition and a variable transition temperature dependent on the MWCNT, IL, and polymeric contents. Finally, the conditions for 3D printing were optimized, and as a proof of concept, we demonstrated the fabrication of a flexible, 3D-printed circuit, which can be bent and twisted without damaging the circuit. Highly conductive, soft, and 3D-printable nanocomposite polymers have been developed that consists of poly (ionic liquid) (PIL), polymethylmethacrylate (PMMA) as polymeric system, multiwalled carbon nanotubes (MWCNTs) as fillers and an ionic liquid (IL) that acts as a plasticizer and dopant for the MWCNTs. The nanocomposites exhibited variable mechanical, conductive, and thermal properties depending on the composition of polymer, IL, and MWCNTs. Finally, we optimized the conditions for 3D printing and demonstrated the fabrication of a flexible, 3D-printed circuit, which can be bent and twisted without damaging the circuit.