Magnetically Responsive Inks for 3D Printing

A 3-D printed device comprising one or more structures, the structures comprising a plurality of magnetically responsive particles and one or more diblock or triblock copolymers; the diblock or triblock copolymers having an A-B, A-B-A, or A-B-C block-type structure in which the A-blocks and C-blocks are an aromatic-based polymer or an acrylate-based polymer and the B-blocks are an aliphatic-based polymer. These 3-D printed devices may be formed using a method that comprises providing a magnetic ink composition; applying the magnetic ink composition to a substrate in a 3-D solvent cast printing process to form one or more structures; and drying the one or more structures formed from the magnetic ink composition. The dried structures can exhibit one or more regions of magnetic permeability greater than 1.3×10−6 H/m.