유모세포를 모사한 유체유동 센서 제작

Abstract

The aim of this work is to design and fabricate a flow sensor using an artificial hair cell (AHC) inspired by biological hair cells of fish. The sensor consists of a single cilium structure with high aspect ratio and a mechanoreceptor using force sensitive resistor (FSR). The cilium structure with 300 μm in diameter and 2mm in height is designed for capturing a drag force with direction due to flow field around the sensor and the mechanoreceptor is designed for sensing the drag force with direction from the cilium structure and converting it into an electric signal. The mechanoreceptor has a symmetric four electrodes to sense the drag force and its direction. To fabricate the single cilium structure with high aspect ratio, we have proposed a new design concept using a separated micro mold system (SMS) fabricated by the LIGA process. For a successful replication of the cilium structure, we used the hot embossing process with the help of a double-sided mold system. We used two materials in hot embossing with different processing conditions

polymethyl methacrylate (PMMA) at temperature of 150oC and pressure 42 of MPa and poly carbonate (PC) at temperature of 170oC and pressure 42MPa. We used a composite of multiwall carbon nanotube and polydimethylsiloxane (MWCNT-PDMS) as sensing material for FSR. A parylene coating with thickness of 3 μm was employed to protect the FSR sensor in underwater environments. We designed an experimental test apparatus consisting of a water channel, a rotating cylinder, a pump, valves, a flow rate measurement system, and a sensor signal measurement system to evaluate the performance of the sensor. We carried out several experiments with the sensor in the different flow rate and direction using this experimental test apparatus. The cross sectional area of the water channel is 30 mm * 15mm and the flow rate in the water channel is controlled from 0 to 70 l/min.