An electrochemically driven poly(dimethylsiloxane) microfluidic actuator: oxygen sensing and programmable flows and...

Area of Science:

• Electrochemistry
• Microfluidics
• Materials Science

Background:

• Microfluidic devices offer precise control over chemical and physical environments.
• Electrochemical reactors are crucial for sensing and chemical synthesis.
• Integrating these fields can lead to novel analytical and manipulation tools.

Purpose of the Study:

• To fabricate and characterize an integrated microelectrochemical reactor.
• To explore its utility in electrochemical sensing, pH gradient generation, and microfluidic flow.
• To investigate the impact of a gas-permeable membrane on reactor performance.

Main Methods:

• Fabrication of a microfluidic device with integrated platinum interdigitated array (IDA) working electrode, counter electrode, and silver pseudo-reference electrode.
• Utilizing a poly(dimethylsiloxane) (PDMS) elastomer as microchannels and a gas-permeable membrane.
• Performing electrochemical experiments, including oxygen reduction reaction (ORR), under mass transport control.

Main Results:

• The microelectrochemical reactor demonstrated significantly higher current densities for ORR compared to conventional cells due to enhanced oxygen diffusion through the PDMS membrane.
• The device functioned effectively as a membrane-covered oxygen sensor with tunable response based on PDMS thickness.
• The reactor was successfully operated as a programmable pH gradient generator and a microfluidic pump.

Conclusions:

• The integrated microelectrochemical reactor is a versatile platform for diverse microfluidic and electrochemical applications.
• The use of a gas-permeable PDMS membrane enhances electrochemical performance, particularly for reactions involving gaseous reactants.
• This design offers a tunable and efficient solution for microfluidic sensing, gradient generation, and fluid manipulation.