An interesting Cytofluidix post highlights recent work by a collaborative team of researchers at both Singapore’s A*STAR’s SIMTech facility and Nanyang Technological University, and at the Seoul National University of Science and Technology, based on their article published in the Journal of Materials Processing Technology.
The focus is on addressing the drawbacks encountered with ultrasonic welding as a bonding technique for plastic microfluidic devices. Ultrasonic welding is attractive because it lends itself to batch processing of microfluidic devices, and employs relatively established, inexpensive and compact equipment. As currently used, however, ultrasonic welding is often not up to the task, from a quality perspective, since uneven energy distribution may distort or melt the microfabricated structures, and air bubbles may also be incorporated.
According to Gary Sum Huan Ng from the SIMTech group, the team’s innovation is to introduce a sandwiched composite film between the two polymer substrates that are to be bonded. The film contains PMMA microspheres within a PDMS matrix, and the microspheres melt during ultrasonic welding, and prevent bubble formation and substrate material flow.