Charge Manipulation Based Selective Functionalization of 3D Printed Structures for Functional Devices

As a rapid prototyping technology, digital light processing (DLP)-based 3D printing has prospect in electronics for its excellent molding speed and accuracy. Although complex and precise models can be obtained by the DLP-based 3D printing, the functionalization of the printed models is still a challenge. Herein, a cost-effective, efficient, and scalable approach based on the electrostatic interaction for the selective deposition of multiwalled carbon nanotubes (MWCNTs) on structures printed by DLP technique is reported. The structures are fabricated by alternatively DLP 3D printing of neutrally and positively charged resins, with positively charged resin for attracting MWCNTs with negative charges. The positive and negative charges come from the cationic groups incorporated into the polymer matrix and the anionic dispersant on the MWCNTs, respectively. By controlling the pH and concentration of the functional material dispersion, as well as the deposition time, the characteristics of the deposited functional materials, including thickness and conductivity, can be modulated. In addition, an all-solid-state supercapacitor is developed by this method, delivering a capacitance of 30 µF cm⁻² and a good electrochemical stability.