Toward High-Fidelity Fabrication: A Refinement Strategy via Decoupled Photopolymerization Modeling and Simulation for...

Area of Science:

• Materials Science
• Chemical Engineering
• Biomedical Engineering

Background:

• Microneedle (MN) array fabrication requires high design-to-fabrication consistency for optimal performance.
• Traditional methods using static models fail to capture nonlinear polymerization kinetics, leading to defects like warping.

Purpose of the Study:

• To develop a photopolymerization kinetic framework for precise control over microneedle array manufacturing.
• To address limitations of traditional models in predicting and preventing fabrication defects.

Main Methods:

• Developed a kinetic framework decoupling exposure intensity and duration.
• Incorporated dynamic light attenuation and polymerization into multiscale finite element analysis using a UMAT subroutine.
• Identified a critical stress-minimization regime by aligning slicing thickness with optical penetration depth.

Main Results:

• Extreme exposure duration or intensity causes over-curing, shrinkage, heterogeneous polymerization, and warpage.
• A critical regime was identified where slicing thickness (30 μm) matched optical penetration depth (≈29.3 μm).
• Fabricated gradient MN arrays achieved 12.8 μm tip precision, a 68% accuracy improvement over conventional methods.

Conclusions:

• The developed model enables quantitatively driven, defect-free manufacturing of microstructures.
• This approach shifts microneedle fabrication from empirical methods to model-guided precision.
• Achieved high geometric fidelity in microneedle arrays, crucial for mechanical and drug delivery performance.