A single additive for 3D printing of highly-concentrated iron oxide inks

Official URL: http://risc01.sabanciuniv.edu/record=b1669826 (Table of Contents)

A single additive, a grafted copolymer, is designed to prepare highly-loaded suspensions of iron oxide nanoparticles (IOPs) and to facilitate the extrusion-based 3D printing of these stable suspensions. This poly (ethylene glycol) (PEG)-grafted copolymer of N- [3(dimethylamino)propyl]methacrylamide (DMAPMA) and acrylic acid (AA) harnesses both electrostatic and steric repulsion to realize an optimum formulation for 3D printing of IOP inks. With the use of 1.15 wt. % (by the weight of IOPs), the suspension attains ~81 wt. % solid loading—96% of the theoretical limit as calculated by the Krieger-Dougherty equation. We fabricated rectangular, thick-walled toroidal, and thin-walled toroidal magnetic cores and a porous lattice structure to demonstrate the utilization of this ink for 3D printing. The electrical and magnetic properties of the magnetic cores were characterized through impedance spectroscopy (IS) and vibrating sample magnetometry (VSM), respectively. The IS indicated the possibility of utilizing wire-wound 3D printed cores as the inductive coils. The VSM confirmed the magnetic properties of IOPs before and after the ink formulation were kept almost unchanged due to the low loading of the additive. This particle-targeted approach for the formulation of 3D printing inks realizes the embodiment of a fully aqueous system with utmost target material content.