Au micro-pattern fabrication on cellulose paper: comparison of μ-contact printing and liftoff techniques

Micro-contact printing (μ-CP) and liftoff techniques were employed to fabricate Au micro-patterns onto electro-active paper (EAPap) for biodegradable and flexible microelectromechanical system (MEMS) application. Conventional lithography and etching techniques cannot be utilized to fabricate micropatterns on EAPap having interesting actuating properties due to its hydrophilic and flexible characteristics. The cause of nanodefects on the Au pattern after the μ-CP process was investigated to enhance the pattern quality. Three different solvents were utilized to investigate the consequence of the solvent polarity during the 3-mercaptopropyltrimethoxysilane (MPTMS) self-assembled monolayer (SAM) fabrication and after the μ-CP process. The defects, such as microcracks and nanograins, were closely related to the solvent polarity. The higher polar solvent turned out smaller defects than the lower polar solvent due to the reduction of the solvent swell onto the PDMS stamp during SAM layer formation. The liftoff technique exhibited a new way of fabricating various metal patterns on EAPap without any nanodefects.