Polymer-Assisted 3D Printing of Inductor Cores

Area of Science:

• Materials Science
• Polymer Chemistry
• Additive Manufacturing

Background:

• Developing high-performance functional devices requires advanced printable inks.
• Iron oxide nanoparticles (IOPs) offer unique magnetic properties but pose formulation challenges for 3D printing.
• Poly(glycerol monomethacrylate) (PGMA) is explored as a rheology modifier for IOP inks.

Purpose of the Study:

• To investigate PGMA as an additive for high-loading IOP 3D printable inks.
• To optimize ink formulation for rheology, printability, and mechanical properties.
• To fabricate and assess the electrical performance of 3D printed inductors using the optimized ink.

Main Methods:

• Reversible addition-fragmentation chain transfer polymerization for PGMA synthesis.
• Rheological characterization of IOP suspensions with varying PGMA molar mass and loading.
• 3D printing of various structures and inductors.
• Mechanical testing (flexural and compressive) post-sintering.
• Electrical performance assessment via impedance spectroscopy.

Main Results:

• An optimized ink formulation (70% w/w IOPs, 0.25% w/w PGMA₉₈, pH 10) was developed.
• Successful 3D printing of complex structures and toroids was achieved.
• Sintering improved mechanical properties; higher temperatures led to enhanced performance.
• 3D printed inductors achieved a Q factor of ~40 at 10 MHz, outperforming previous iron oxide core devices.
• A trade-off between electrical properties and sintering temperature was observed due to phase changes in iron oxide.

Conclusions:

• PGMA is an effective additive for creating high-loading, aqueous, 3D printable IOP inks.
• The developed ink and printing process enable fabrication of high-performance inductors.
• This work advances the development of low-cost, functional ceramic devices via additive manufacturing.