3D-Printable Carbon Nanotubes-Based Composite for Flexible Piezoresistive Sensors

Abstract

The intersection between nanoscience and additive manufacturing technology has resulted in a new field of printable and flexible electronics. This interesting area of research tackles the challenges in the development of novel materials and fabrication techniques towards a wider range and improved design of flexible electronic devices. This work presents the fabrication of a cost-effective and facile flexible piezoresistive pressure sensor using a 3D-printable carbon nanotube-based nanocomposite. The carbon nanotubes used for the development of the material are multi-walled carbon nanotubes (MWCNT) dispersed in polydimethylsiloxane (PDMS) prepolymer. The sensor was fabricated using the direct ink writing (DIW) technique (also referred to as robocasting). The MWCNT-PDMS composite was directly printed onto the polydimethylsiloxane substrate. The sensor response was then examined based on the resistance change to the applied load. The sensor exhibited high sensitivity (6.3 Ω/kPa) over a wide range of applied pressure (up to 1132 kPa); the highest observed measurement range for MWCNT-PDMS composite in previous work was 40 kPa. The formulated MWCNT-PDMS composite was also printed into high-resolution 3-dimensional shapes which maintained their form even after heat treatment process. The possibility to use 3D printing in the fabrication of flexible sensors allows design freedom and flexibility, and structural complexity with wide applications in wearable or implantable electronics for sport, automotive and biomedical fields.

Recent Advances in Electronic Skins with Multiple-Stimuli-Responsive and Self-Healing Abilities

“…As for flexible and stretchable supporting polymer matrix, elastic rubbers, fibers, fabrics, and foams are the popularly used ones for flexible force-sensitive sensors [ 5 , 9 , 11 ]. Up to date, enormous efforts have been devoted to improving the important sensing parameters of wearable force sensors via different chemical and morphological structure design, such as sensitivity, stretchability, hysteresis and response time [ 43 , 44 , 45 , 46 , 47 ]. Nevertheless, if state-of-the-art flexible e-skin are highly desirable, other skin-like force-response performance should be taken into consideration.…”

3D Printed Flexible Microscaled Porous Conductive Polymer Nanocomposites for Piezoresistive Sensing Applications

“…[27] DIW has been used in literature for the synthesis of solid PDMS nanocomposites for piezoresistive sensing applications. [28,29] Besides, 3D structures have been fabricated using DIW by controlling infill densities and print patterns, leading to printed structural macro-scaled Porosity with applications as flexible sensors. [30,31] However, DIW of porous structures with 100% infill density and microscale pores has been challenging.…”

Printed flexible mechanical sensors

“…118 DIW is another favored method to fabricate flexible pressure sensors. As a versatile printing technique, DIW can work with a wide variety of materials from MWCNTs/PDMS ink 119 to silver ink. 120 Various components can be printed with this technique, including the dielectric layer, 119 electrodes, 120 substrate, 57 and the sensing element.…”