Printing Completely Conformal Liquid Metal Circuits on Arbitrary Curved Surfaces via Customized Conformal Mask

Abstract

Due to the excellent mechanical adaptability to curved surfaces and high circuit flexibility, conformal electronics have been developed for extensive applications including aeronautics and wearable electronics. However, conventional methods for fabricating conformal circuits are often constrained by planar structures, limiting the design flexibility and applicability of electronic devices on more complex and varied surfaces. Herein, a facial approach is proposed by combining a 3D‐printed customized conformal mask with liquid metal inkjet printing, to establish the completely conformal liquid alloy circuits’ printing technique on arbitrary curved surfaces. A 2D transient mathematical model is developed to simulate the particle deposition process during inkjet printing and the form of the circuits on curved surfaces is predicted. Moreover, parameters such as line resistance and cross‐sectional morphology of liquid metal circuits on both deformable and nondeformable surfaces are characterized. Various conformal liquid metal circuits, such as contour lines, expressions, text patterns, light‐emitting diode (LED) array illumination patterns, and multichannel pressure array intelligent skin on curved surfaces, are demonstrated. Compared to traditional conformal electronics manufacturing methods, this new approach offers the advantages of simple process, flexibility, low cost (within $0.01 cm−2), and high efficiency (exceeding 1 cm2 s−1), making it suitable for mass conformal electronics production.