Polymeric materials containing hierarchical structures ranging from micrometer to nanometer feature sizes play a significant role in accelerating transport properties, critical for energy-water and biomedical applications. Major advances in light-based additive manufacturing (AM) have demonstrated the capability of creating architected materials at the micrometer resolution with high-speed and resolution. Nevertheless, critical challenges exist in achieving sub < 500nm structure with desirable thermal-mechanical properties. To address these challenges, fundamental questions we seek to answer in our lab include: (1) How can we approach sub-diffraction limit fabrication resolution? (2) How does AM processing impact material structure and properties? (3) How can we bridge the tradeoffs between thermal-mechanical tunability and processability compatible with light-based AM?
In the first part of the talk, I will focus on the introduction of dual-wavelength 3D printing platform coupled with controlled living radical polymerization to tackle the diffraction-limited patterning resolution. The critical timescales of reaction-diffusion mechanism are elucidated with experiment, simulation and theory.1 This work indicate a path forward in achieving sub-diffraction limited resolution patterning, and how diffusion governs inter-material boundary under multi-wavelengths exposure. In the second part of the talk, I will discuss how flow field and reaction kinetics in micro-CLIP AM platform impacts structural evolution during photopatterning of self-assembled amphiphilic macromolecules, elucidated with SAXS and SEM.2 In the last part of my talk, I will introduce the development of dual-cure resin development and processing that allows us to maintain high-resolution patterning while achieving high material toughness and stretchability. Taken together, our research aims to understand the fundamental transport phenomena within AM platforms, including reaction kinetics and flow field to control polymer structure and property.