Understanding the hydrodynamic behavior in microfluidic devices is crucial for utilization of these systems in lab-on-a-chip applications. However, hydrodynamic capacitance in microfluidic devices causes a delay and mismatch between the applied pressure and actual pressure in the microchannel. Therefore, real-time monitoring of the site-specific internal pressure in microchannels is important for designing the operating conditions of the system. We introduce a deformable colloidal crystal membrane composed of polystyrene (PS) colloidal crystals and poly(dimethylsiloxane) (PDMS) and its integration into a PDMS microfluidic device. As pressure is applied to the device, the optical intensity reflected back from the colloidal crystal membrane changes due to membrane deformation. The optical signal originating from structural deformation of the colloidal crystal membrane allows the realization of a real-time pressure monitoring system, as no external apparatus or powering devices are required for signal processing. The internal pressure in microfluidic devices was also monitored to investigate the effect of the hydrodynamic capacitance during pressure application.
This work was supported by a National Research Foundation of Korea (NRF) grant, funded by the Korean Government (MSIT) (2019R1F1A1062058). This work was also supported by the Human Resources Program in Energy Technology (No. 20154010200820) of the Korea Institute of Energy Technology Evaluation and Planning (KETEP), which is granted financial resources from the Ministry of Trade, Industry, and Energy of the Republic of Korea. This work was also supported by the GRRC program of Gyeonggi province (GRRCAJOU2016B03, Photonics-Medical Convergence Technology Research Center).
