This paper reports on a chip cooling solution using polydimethylsiloxane (PDMS) based microfluidic devices filled with n-Octadecane. A thick SU-8 layer of 150 µm is used as the master mold for patterning PDMS fabrication. With the SU-8 mold, patterns with straight lines at microscale have been fabricated with standard micro-electro-mechanical system (MEMS) technology. Thermal polymer bonding technique is used to bond the PDMS pattern directly to a flat polydimethylsiloxane (PDMS) film which results in the sealed microchannels. n-Octadecane as a phase-change material has been successfully filled in the microchannels using a dispensing machine. Infrared thermal image shows a sharp contrast of the temperature distribution between the chip with n-Octadecane and the empty chip during the same heating process. This result indicates an efficient cooling performance of the microchannel device with phase-change material. A thermal stimulation test demonstrates that a 16 °C-lower temperature difference can be achieved. This microchannel device, benefited from the flexibility of PDMS substrate, shows specific advantages in meeting the need for the heat dissipation of flexible electronics such as flexible displays, electronic skins, and wearable electronics. Latent heat of the phase-change material can keep the temperature of devices relatively lower over a period of time, which shows potential application values on discontinuously active flexible electronic devices.
Keywords: MEMS; chip cooling; flexible electronics; micro-channel device; phase-change material; polymer; thermal management.