Simple method for PDMS bonding using flame treatment
In order to demonstrate this method, two pieces of flat PDMS (with the mixing ratio of 1:10, area of 2 x 1.5 cm2, thickness of 3mm) were uniformly treated by a piezojet torch (which generates a butane flame) based on the sequential pattern shown.
In this treatment, the distance between the torch and substrates was ~1.5 cm. Next, two treated surfaces were contacted and kept in 85 oC oven for 24 hrs. This process was found to create a remarkably strong bond between two substrates. To investigate the strength of the bonding, tensile tests were performed. A half dog-bone shape (with section diameter of 8mm) of PDMS (n=5) was casted and flame treated. Next, the sample was bonded to another 1.5 x 1.5 cm2 PDMS substrate, which underwent the same flame treatment (Fig. 1). After bonding, samples were placed into 85 oC oven for 24 hrs.