Balancing Functionality and Printability: High-Loading Polymer Resins for Direct Ink Writing

Area of Science:

• Materials Science
• Additive Manufacturing
• Polymer Chemistry

Background:

• Direct ink writing (DIW) enables rapid 3D printing but lacks diverse, functional inks.
• Developing custom inks is crucial for expanding DIW applications.
• Assessing ink "printability" is essential for successful fabrication.

Purpose of the Study:

• To investigate the impact of filler composition, concentration, printing parameters, and lattice structure on the printability of novel polysiloxane-based DIW inks.
• To explore the performance of inks with high filler loadings (50-70 wt%) of metallic, ceramic, and emulsion components.
• To provide insights into the trade-offs between ink development, printability, and final material properties.

Main Methods:

• Formulation of polysiloxane inks with varying metallic, ceramic, and emulsion fillers at high concentrations (50-70 wt%).
• Systematic evaluation of printing parameters and lattice structures (e.g., strut diameter, spacing ratio, SC vs. FCT geometries).
• Analysis of printability, part stiffness, and thermal stability of the fabricated 3D printed objects.

Main Results:

• Strut diameter and spacing ratio were identified as the most influential factors on DIW material printability.
• Silica- and metal-filled inks demonstrated more predictable printability compared to ceramic-filled inks.
• Higher filler loadings and specific lattice geometries (SC) resulted in stiffer printed parts; metal-filled inks exhibited superior thermal stability.

Conclusions:

• The study highlights key factors influencing the printability and performance of high-filler-loaded DIW inks.
• Findings offer guidance for developing custom, multifunctional inks for direct ink writing applications.
• Understanding the interplay between ink formulation, printing parameters, and structural design is critical for optimizing 3D printed material performance.