Rapid prototyping of micro/nano poly (methyl methacrylate) fluidic systems using proton beam writing

A technique has been developed for the rapid prototyping of enclosed micro/nano polymethyl methacrylate (PMMA) fluidic systems using proton beam writing (PBW) and thermal bonding. Micro/nano structures consisting of channels and reservoirs were fabricated in a PMMA resist layer coated on to a Kapton substrate using a focused MeV proton beam. By thermal bonding these structures are fixed to a top bulk housing of PMMA, peeling off the Kapton substrate, and bonding the remaining exposed side to PMMA, enclosed high-aspect-ratio nano/microchannels can be fabricated. The key to the process is bonding the PMMA housing to the patterned resist under suitable conditions, to ensure that the bond strength is higher than the adhesion between the resist to the Kapton substrate, while ensuring that the deformation of the patterned structures caused by bonding temperature and pressure is minimised. Experiments showed that the optimum bonding condition is at 105 °C with a pressure of 1.2 Bar for 2 h.