Fabrication of flexible microheater with tunable heating capabilities by direct laser writing and selective electrodeposition

Flexible microheaters are useful in a variety of fields, such as portable medical instruments, wearable electronic devices, aircraft, and many more. The microheaters that can provide thermal stimuli in a series of small regions have received considerable attention in recent years. In this work, we present a novel manufacturing process for flexible microheaters with designed heating patterns. Such flexible microheaters with customized heating patterns are fabricated using a hybrid manufacturing process that combines direct laser writing, 3D printing, and selective electrodeposition to control the deposition of graphene and copper on a polyimide film. Based on a given heating pattern, a laser-induced graphene (LIG) structure is utilized as the active heating material, and selectively electrodeposited copper defined by 3D-printed masks is used as the electrode material to connect LIG. The width of the heating line can be as small as 60 μm. The total processing time of a typical 60 mm × 30 mm microheater was within 20 min. When connected to electricity, the fabricated microheaters have tunable heating temperatures at designed heating areas. The heating temperature can reach up to 150 °C. Moreover, the microheaters have shown quick heating and stable thermal performance when subjected to bending, twisting, and folding. Compared with the existing microheater fabrication methods, the newly developed manufacturing process is simple to operate and has the advantages of high accuracy (up to 60 μm heating line width), flexible tunability, and low cost (within $5) compared with other conventional microfabrication methods.