Effect of Fumed Silica Nanoparticles on the Performance of Magnetically Active Inks and DIW Printing

Magnetically active soft materials (MASMs) demonstrateconsiderablepotential for applications in sensors, biomedicines, and bionic andsoft robotics. However, owing to the low viscosity of unmodified MASMswith weak molding stacking ability, these materials cannot be printeddirectly, making the fabrication of MASMs with complex structures.A modified MASM printing ink and its preparation method are proposedfor the problem of material and printing process of MASM 3D, and theeffects of fumed silica nanoparticles as the modifier on the rheologicaland mechanical properties of MASM ink were experimentally analyzed.A direct ink writing (DIW) three-dimensional (3D) printing processusing MASM printing inks was also proposed. To obtain a highly accurateand stable printing process, the influence of process parameters suchas printing speed, nozzle diameter, printing air pressure, and inkviscosity on the ink line width was analyzed. The experimental resultsshow that the MASM objects with different characteristics and structurescan be printed stably and with high accuracy, reflecting the feasibilityof the proposed MASM ink and DIW 3D printing process. To further validatethe characteristics of the DIW 3D-printed MASM objects, a MASM gripperwas fabricated using the prepared MASM ink with DIW 3D printing. Themagnetization-programmed MASM gripper exhibited excellent magneticresponse and excellent gripping and shape-adaptation capabilities.The gripping force was & SIM;294 mN. Under the driving magneticfield of 270 mT, the gripping force can be more than 1765% of theweight of the gripper (1.7 g). The results of this study show thatthe proposed MASM printing ink with the DIW 3D printing process canbe used for various applications with high performance.