Liquid glass electrodes for nanofluidics.

Area of Science:

• Nanotechnology and Materials Science
• Microfluidics and Nanofluidics

Background:

• Nanofluidic devices leverage molecular phenomena for enhanced performance but face fabrication challenges due to complex 3D integration of dissimilar materials at the nanoscale.
• Existing methods often require conductive materials and struggle with precise nanoscale assembly.

Purpose of the Study:

• To develop a novel, fabrication-friendly nanoscale electrode for advanced nanofluidic applications.
• To demonstrate a reversible, field-induced conductive glass electrode for precise fluid manipulation.

Main Methods:

• Fabrication of a 3D nanoscale liquid glass electrode from monolithic substrates using femtosecond-laser nanomachining.
• Characterization of the electrode's dielectric breakdown and reversible conductive properties under high electric fields.
• Integration of the electrode into a nano-injector with an electrokinetic pump for controlled fluid flow.

Main Results:

• A nanoscale glass electrode was successfully fabricated without conductive materials, featuring a nanochannel ending in a nanoscale glass tip.
• The glass tip exhibits reversible dielectric breakdown, acting as a conductor under high electric fields and an insulator when removed.
• A nano-injector with controlled flow rates below 1 femtoliter per second was demonstrated using the developed electrode and an electrokinetic pump.

Conclusions:

• Femtosecond-laser nanomachining enables the creation of novel, monolithic nanoscale liquid glass electrodes with unique electrical properties.
• The reversible dielectric breakdown mechanism offers a new approach for precise control in nanofluidic systems.
• The developed electrode is easily integrable into various nanodevices, including sensors and actuators, paving the way for advanced micro/nanofluidic applications.