Flexible 3D Printed Acrylic Composites based on Polyaniline/Multiwalled Carbon Nanotubes for Piezoresistive Pressure Sensors

Abstract

Abstract The development of tunable UV‐curable polymeric composites for functional applications, taking into consideration environmental issues and additive manufacturing technologies, is a research topic with relevant challenges yet to be solved. Herein, acrylic composites filled with 0–3 wt.%. polyaniline/ multiwalled carbon nanotubes (PANI/MWCNT) are prepared by Digital Light Processing (DLP) in order to tailor morphology, thermal, mechanical, and electromechanical properties. Viscosity, real‐time infrared spectroscopy, and cure depth tests allow optimizing resin composition for suitable DLP printing. 2 wt.% is the maximum filler content reproducibly embedded in the polymer matrix. The advantages of PANI/MWCNT (50/50 wt.%) compared with single‐component composites include safety issues, enhanced printability, increased electrical conductivity and thermal stability, and lower electrical percolation threshold (0.83 wt.%). Above this threshold the composites display excellent piezoresistive response, no hysteresis, and stability for over 400 compression cycles. The pressure sensibility (PS) of 2 wt.% composites decreases with applied pressure from PS ≈ 15 to 0.8 Mpa −1 for maximum pressures of 0.02 and 0.57 MPa, respectively. A proof‐of‐concept of the functionality of the novel materials is developed in the form of a tactile sensor, demonstrating their potential for pressure sensing applications as cost‐effective, sustainable, and flexible materials for printed electronics.