2025 AIChE Annual Meeting

(378b) Hierarchical Nanoporous Structures Via CLIP Printing of Lyotropic Liquid Crystal Template

Authors

Weiling Xia - Presenter, University of Wisconsin-Milwaukee
Hierarchical porous materials with well-defined structures spanning multiple length scales are highly desirable for applications requiring efficient mass transport and high surface-to-volume ratio. However, conventional fabrication methods rely on either harsh chemical etching or complex post-treatment processes that limit pore size control and scalable, reproducible production. Herein, we report an approach combining high-resolution continuous liquid interface production (CLIP) printing with lyotropic liquid crystal (LLC) guided soft-templating to create hierarchically porous structures with tunable porosity from nanometer to millimeter length scales. The LLC precursor mixtures self-assemble into bi-continuous and lamellar mixed phases, as confirmed by polarized light microscopy (PLM) and small-angle X-ray scattering (SAXS). Specifically, SAXS analysis reveals characteristic d-spacing values of 60 Å, 54 Å, and 52 Å with increasing LLC concentration, demonstrating a decrease in domain spacing as the system becomes more densely packed. During UV photopolymerization, entropic-driven depletion interactions between the polymerized network and LLC template domains coarsen the self-assembled nanostructures, forming enlarged yet organized porous networks. SEM reveals decrease in average pore diameters from 409 nm, 271 nm, to 172, along with narrower pore size distribution as LLC concentration increases. The approach and mechanism reports herein demonstrates the capability to control hierarchical porosity spanning multi-length scales, offering new opportunities for designing materials with accelerated mass transport with potential applications at the energy and water nexus.