An electrokinetic pressure sensor

Abstract

A new concept for a micro pressure sensor is demonstrated. The pressure difference between the inlet and the outlet of glass nanochannels is obtained by measuring the electrokinetically generated electric potential. To demonstrate the proposed concept, experimental investigations are performed for 100 nm wide nanochannels with sodium chloride solutions having various concentrations. The proposed pressure sensor is able to measure the pressure difference within a 10% deviation from linearity. The sensitivity of the electrokinetic pressure sensor with 10 −5 M sodium chloride solution is 18.5 µV Pa −1 , which is one order of magnitude higher than that of typical diaphragm-based pressure sensors. A numerical model is presented for investigating the effects of the concentration and the channel width on the sensitivity of the electrokinetic pressure sensor. Numerical results show that the sensitivity increases as the concentration decreases and the channel width increases.

Electrokinetic energy conversion in micrometer-length nanofluidic channels

“…The action of the streaming potential generates an electrical current called the conduction current in the opposite direction of the streaming current. Recently, the streaming potential and the streaming current have been widely employed in the application of microfluidic and nanofluidic devices, including f-potential measurements (Kirby and Hasselbrink 2004;Zimmermann et al 2006), flow rate meters (Kim et al 2007a), pressure sensors (Kim et al 2008), and micro/nanofluidic-based batteries (i.e., electrokinetic energy conversion in the generation mode) (Yang et al 2003(Yang et al , 2005Lu et al 2006;Olthuis et al 2005). In general, there are two modes for electrokinetic energy conversion: (i) the generation mode and (ii) the pumping mode.…”

Fundamentals and Modeling of Electrokinetic Transport in Nanochannels

“…The feasibility for harvesting power (either mechanical or electrical) via the electrokinetic energy conversion (EKEC) process within nanoscale fluidic confinements has attracted significant attention in the literature. Recently, the streaming current and streaming potential have been widely employed in the application of microfluidic and nanofluidic devices, including flow rate meters,41 pressure sensors,42 zeta potential measurements,43 and electrokinetic batteries 15…”

Ion bridges in microfluidic systems

“…In the depletion mode, the depletion region is formed due to the concentration polarization and then in the trapping mode, the molecules driven with an electroosmotic flow are electrokinetically trapped in front of the depletion region, resulting in increased concentration (Lee et al 2008b) across the nanochannel array (Kim et al 2008b). The working principle of this device was reported by Kirby and Hasselbrink (2004a).…”