Low-temperature bonding of poly-(methyl methacrylate) microfluidic devices under an ultrasonic field

High bond strength at low temperature without shape distortion is a major goal in microfluidic device fabrication. In this paper, we present a new easy bonding method for poly-(methyl methacrylate) ( PMMA) microdevices at low temperature in an ultrasonic field. The ultrasonic energy spot effect at an interface could lead to a high bond strength up to 30 mJ cm(-2) at only 60 degrees C. This bond strength is tens of times higher than the typical value in the literature (Tsao et al 2007 Lab. Chip. 7 499). The benefit from the low bonding temperature is that no deformation of the channel was evident. Few changes in the substrate surface property were observed. The static water contact angle of the bonded substrates had a small decrease compared to that of the virgin ones. The bonded microchannel devices were not reduced in transparency and smoothness. This method is batch-production oriented because many microdevices could be bonded at one time.