Date of Award
8-19-2024
Document Type
Open Access Dissertation
Department
Chemical Engineering
First Advisor
Monirosadat Sadati
Abstract
This thesis delves into the intricate realm of 3D printing bio-inspired materials with tailored nano/microscale architectures. The first chapter investigates the flow-induced alignment of cellulose nanocrystals (CNC) during 3D printing, employing a microfluidic strategy integrated with polarized optical microscopy (POM). Birefringence measurements under varying conditions reveal the influence of initial CNC suspension structures on flow-induced patterns, particularly in the chiral nematic phase. Hydrodynamic simulations complement experimental findings, elucidating the impact on CNC particle alignment, providing insights for designing 3D printed architectures with internal chirality for advanced applications.
The second chapter explores the 3D printing of complex geometries inspired by Bouligand structures, utilizing cellulose nanocrystal (CNC)-based inks. Through detailed rheological measurements, in-situ flow analysis, and POM, the study elucidates the role of shear flow in orienting CNC particles, forming concentric chiral nematic structures post-flow. Acrylamide incorporation enables arresting concentric chiral arrangements within a cross-linked polymeric network, while the rate of chiral relaxation after ink deposition strongly depends on the ink composition. Carbopol microgels support liquid-like inks before photo-polymerization, enabling larger-scale bio-inspired constructs. This multidimensional approach not only advances chiral assembly understanding but also opens avenues for creating biomimetic materials with tailored structures and enhanced properties.
In the third chapter, the integration of helical/chiral assembly and 3D printing technology is explored. Reactive chiral inks based on CNC suspensions and acrylamide monomers enable precise spatial control over chiral nano/microstructures. Orthogonal Superposition rheometry and in-situ rheo-optic measurements unravel nonlinear flow behavior, microstructural dynamics, and phase transitions. Insights into photo-curing processes guide the out-of-equilibrium arrangement of CNC particles in 3D printed filaments, offering control over nano/microstructures and suggesting applications in materials with superior mechanical properties or programable photonic responses.
The fourth chapter delves into fabricating organic/inorganic hybrid materials with superior mechanical properties, drawing inspiration from biological materials with long-order complex chirality. The UV-assisted embedded ink writing technique is employed to 3D print cellulosic templates with a concentric configuration of chiral structures. Modification of organic templates facilitates nucleation sites for biomineralization, resulting in artificial hybrid materials with reinforced mechanical properties through the synergistic effects of uniformly aligned chiral assemblies and incorporated biominerals.
This multidisciplinary exploration not only advances our understanding of bio-inspired 3D printing but also opens avenues for designing materials with enhanced properties across various scales.
Rights
© 2024, Mohsen Esmaeili
Recommended Citation
Esmaeili, M.(2024). Guiding 3D Chiral Self-Assembly at Nano/Micro Length Scales Via 3D Printing. (Doctoral dissertation). Retrieved from https://scholarcommons.sc.edu/etd/7708