Pressure-Driven Micro-Casting for Electrode Fabrication and Its Applications in Wear Grain Detections

Abstract

The microelectrode is an essential and vital part in microsensors that are largely used in industrial, chemical, and biological applications. To obtain desired microelectrodes in great quality, it is also of great necessity and significance to develop a robust method to fabricate the microelectrode pattern. This work developed a four-terminal differential microelectrode that aims at recognizing microparticles in fluids. This microelectrode pair consisted of a high height–width ratio microelectrode array fabricated using a pre-designed microelectrode pattern (a micro-scale channel) and melted liquid metal. The surface treatment of microelectrodes was also investigated to reveal its impacts on the continuality of melting metal and the quality of the fabricated microelectrode patterns. To evaluate the performance of micro-casting fabricated electrodes, a microfluidic device was packaged using a microelectrode layer and a flow layer. Then impedance cytometer experiments were performed using sample fluids with polymer particles in two different sizes in diameter (5 μm and 10 μm). In addition, engine oil was tested on the microelectrodes as complex samples. The number of abrasive particles in the engine oil can be collected from the developed microfluidic device for further analysis.

Rapid Fabrication of Poly(methyl methacrylate) Devices for Lab-on-a-Chip Applications Using Acetic Acid and UV Treatment

“…In particular, biosensor-based devices containing a thin metal film as a microelectrode have been used for temperature measurement, separation, and detection. 14 , 15 Mainly, thermal bonding and glue-assisted bonding were used to create microdevices integrated with electrodes. 16 − 19 Although the thermal bonding method is widely applicable, the risk of fractures on the integrated metal electrode still remains because of the high bonding temperature and pressure, 20 whereas glue-assisted bonding faces the possibility of microchannel clogging.…”

“…These devices have a significantly increased sensitivity and accuracy than commercial sensors. In particular, biosensor-based devices containing a thin metal film as a microelectrode have been used for temperature measurement, separation, and detection. , Mainly, thermal bonding and glue-assisted bonding were used to create microdevices integrated with electrodes. − Although the thermal bonding method is widely applicable, the risk of fractures on the integrated metal electrode still remains because of the high bonding temperature and pressure, whereas glue-assisted bonding faces the possibility of microchannel clogging. As an alternative, an elastomeric substrate such as poly­(dimethylsiloxane) (PDMS) was used as a part of microdevices integrated with metal electrodes.…”

Label-Free Sensing of Cell Viability Using a Low-Cost Impedance Cytometry Device

“…However, the accuracy and sensitivity of the liquid electrodes were poor, and the conductive solution of the liquid electrodes was suspected to potentially contaminate sample solutions. Recently, Cheng et al [ 24 ] used molten liquid metal for the 3D-detection electrodes in their device by using a Sn42Bi58 alloy solder wire instead of conventional electrode materials (e.g., Au and Cr). Instead of making conventional electrodes, they melted the Sn42Bi58 alloy solder wire into metal liquid and injected the melted alloy into the microelectrode layer at a controlled driving pressure.…”