Direct‐Printing of Functional Nanofibers on 3D Surfaces Using Self‐Aligning Nanojet in Near‐Field Electrospinning
Dongwoon Shin, Sun Choi, Jong-Hyun Kim, Abiral Regmi, Jiyoung Chang
Abstract
Abstract This paper reports a high‐resolution, template‐free, and direct‐printing method of functional nanofiber on 3D surfaces using a self‐aligning nanojet (SA‐N) in near‐field electrospinning (NFES). In the lowest regime of NFES, the cone‐jet transition is induced by the surface current, which leads to a unique jetting configuration where the microscale Taylor cone (microcone) is formed on the surface of the spherical‐shape droplet. The microcone rapidly develops to the nanoscale jet where the tangential electric force dominates the kinematics of the charged jet. The spherical‐shape ejection boundary allows the jetting angle from 0° to ±90° in both convex and concave surfaces, enabling precise deposition of nanofiber regardless of the curvature of the 3D surfaces. Using SA‐N, precise printing of functional nanofiber is successfully demonstrated on various 3D geometries, including convex, concave, and inner surface of the 3D structure. The direct‐printing ability of nanofiber on 3D surfaces using SA‐N will be a promising strategy to utilize various functional polymers in flexible electronics, printed electronics, optics, and biomedical engineering.