Hydration-triggered adhesion switching for transfer printing of conductive patterns using carboxymethylated cellulose nanofibers films

Complex 3D devices require a printing technique for curved geometries under mild conditions. Here, effective 3D transfer printing is achieved by simple water-assisted adhesion switching using a cellulose nanofiber (CNF) film. Patterns printed on the CNF film are transferred to target surfaces by simple hydration of the CNF film. As the CNF film gradually hydrates, the hydrogen bonding between the printed patterns and the film surface weakens. This reduction in adhesion allows the easy delamination of patterns from the CNF film and the spontaneous transfer to target surfaces such as polymers, ceramics, and metals, which have stronger adhesion than the hydrated CNF surface. This hydration-triggered process enables both high-fidelity printing on curved surfaces and functional integrity and easy repair of electrical devices, paving the way for advanced fabrication of flexible electronic circuits.