(CANCELED) A Hydrophobicity Controlled Nanofluidic Pump
H. Liu, S. Dharmatilleke, A.A.O. Tay
Institute of Materials Research and Engineering, SG
Keywords: hydrophobic, electrowetting-on-dielectric(EWOD), nanofluidic, surface tension, pump
Abstract:interfacial energies in the system. Many methods for modulation of surface tension to manipulate fluids in micro or nano scale have been studied and reported, including the mechanical (surface roughness effect), chemical (electrochemical effect), opto- (photochemical effect), thermal (thermocapillary effect) and electrical (electrowetting, electrowetting-on-dielectric (EWOD)) method well before 1990. However, high driving voltage and power consumption, bulky size, difficulty in miniaturization and additional pre-processing equipment for the development and implementation of surface tension based micro/nanofluidic systems and devices have always challenged the researchers. Here we demonstrate in this letter, a device utilizing electrically controllable surface tension as the driving force to deliver fluid flow in the order of nanoliters per minute or even smaller without a dedicated actuator. This device is capable of pumping a continuous liquid column. It also has an inbuilt metering feature to precisely determine the flow rate without an additional flow sensor. The experimental results show that the fluid flow of water can be electrically actuated successfully to propagate in the microchannel at a flow rate of 18 nl/min under a potential of as low as 20 V. It is very attractive for applications which require an ultra miniaturized metering pump operated at a low voltage, such as environmental monitoring, chemical analysis systems, implantable medical devices, drug delivery systems and diagnostic systems.