One-step formation of three-dimensional interconnected T-shaped microstructures inside composites by orthogonal...

Area of Science:

• Materials Science
• Polymer Science
• Nanotechnology

Background:

• Achieving 3D percolation pathways in polymer composites requires fillers to self-assemble horizontally and vertically.
• Conventional dielectrophoresis methods are limited to one-dimensional filler alignment.

Purpose of the Study:

• To develop a one-step dielectrophoresis approach for inducing orthogonal bidirectional self-assembly of fillers.
• To create 3D interconnected T-shaped iron microstructures (3D-T CIP) within a polymer matrix.

Main Methods:

• Utilized a one-step dielectrophoresis technique with an AC electric field and a non-contact method.
• Employed in situ optical microscopy for real-time observation of 3D-T CIP formation.
• Applied statistical and fractal analysis for characterization, supported by finite element simulations.

Main Results:

• Successfully induced fillers to self-assemble along two orthogonal axes, forming 3D-T CIP.
• Achieved a linear structure along the thickness and a network structure on the surface.
• Identified an insulating polyethylene terephthalate (PET) film as crucial for 3D-T CIP formation.

Conclusions:

• The developed method offers a superior alternative to traditional two-step fabrication processes.
• The resulting 3D electrically conductive pathways in 3D-T CIP films are suitable for magnetic field sensor applications.