Electric field-driven microscale 3D printing of flexible thin-walled tubular mesh structures of molten polymers

Abstract

Thin-walled tubular mesh structures are the basic form of tubular scaffolds, such as vascular and nerve conduit stents, in tissue engineering. A novel electric field-driven microscale three-dimensional printing (EFD μ-3D printing) was proposed for manufacturing these structures of molten polymers with high resolution. For printing on curved substrates, the distributions of electric field force on substrates with different curvature radii in the self-excited electrostatic field were revealed via numerical simulations. The optimal process parameters for EFD μ-3D printing on curved substrates were determined. To improve printing accuracy, a micro-area preset eccentricity strategy was proposed by reducing the vertical angle of printing jets. A number of printing cases have been carried out. It is shown that the proposed method is effective for the micro-nano scale printing of 3D structures. The printed structures have good flexibility; they can be restored to their original state after 8.9 % axial compression, with an original length of 67 mm. Moreover, a conformal printing variable stiffness thin-wall tubular mesh structure has been achieved with a length of 28 mm, a line diameter of 80 μm, a big end diameter of 8 mm, and a small end diameter of 4 mm.