Computational Study of Drop-on-Demand Coaxial Electrohydrodynamic Jet and Printing Microdroplets

Area of Science:

• Materials Science
• Nanotechnology
• Fluid Dynamics

Background:

• Coaxial electrohydrodynamic jet (CE-Jet) printing is a template-free technique for micro- and nanoscale fabrication.
• Existing methods require further optimization for stability and precision.

Purpose of the Study:

• To numerically simulate the drop-on-demand (DoD) CE-Jet printing process using a phase field model.
• To optimize working parameters for stable CE-Jet printing and microdroplet formation.

Main Methods:

• Numerical simulation of the DoD CE-Jet process based on a phase field model.
• Experimental verification using Titanium lead zirconate (PZT) and silicone oil.
• Optimization of parameters including inner liquid flow velocity, pulse voltage, external fluid velocity, and print height.

Main Results:

• The numerical model accurately simulated the CE-Jet printing process.
• Optimized parameters (e.g., 150 m/s inner flow, 8.0 kV pulse voltage) ensured CE-Jet stability and prevented bulging.
• Direct printing of microdroplets with a minimum diameter of approximately 5.5 µm was achieved after outer solution removal.

Conclusions:

• The phase field model provides an effective and easily implementable tool for simulating CE-Jet printing.
• This technique shows significant potential for advanced manufacturing, particularly in flexible printed electronics.