Bonding of planar poly (methyl methacrylate) (PMMA) nanofluidic channels using thermal assisted ultrasonic bonding method

Because of extremely small dimensions of nanochannels and low rigidity of polymer, most bonding techniques which are suitable for sealing polymer microscale channels (width and depth in tens to hundreds microns) are not competent for bonding of polymer nanochannels. In this study, a new thermal assisted ultrasonic bonding method for sealing poly (methyl methacrylate) (PMMA) nanochannels was presented. Substrates were preheated to 30–40°C lower than glass transition temperature (T g ) of the material by hot plate. Then low amplitude ultrasonic vibration was employed to generate facial heat at the interface of the substrates. Influences of preheating temperature on bonding strength and dimension loss were studied. The nanochannels were successfully bonded with depth loss less than 5.3% (10.6 nm) and bonding strength of 0.21 J/cm2 at the preheating temperature of 70°C. Thermal assisted ultrasonic bonding is proven to be competent for bonding of polymer nanochannels with high bonding strength, low dimension loss and short bonding time.