Engineering Nano/Microscale Chiral Self‑Assembly in 3D Printed Constructs  

作　　者：Mohsen Esmaeili Ehsan Akbari Kyle George Gelareh Rezvan Nader Taheri‑Qazvini Monirosadat Sadati 

机构地区：[1]Department of Chemical Engineering,University of South Carolina,Columbia,SC 29208,USA [2]TA Instruments,Waters LLC,New Castle,DE 19720,USA [3]Biomedical Engineering Program,University of South Carolina,Columbia,SC 29208,USA

出　　处：《Nano-Micro Letters》2024年第3期313-332,共20页纳微快报（英文版）

基　　金：the support from the University of South Carolina

摘　　要：Helical hierarchy found in biomolecules like cellulose,chitin,and collagen underpins the remarkable mechanical strength and vibrant colors observed in living organisms.This study advances the integration of helical/chiral assembly and 3D printing technology,providing precise spatial control over chiral nano/microstructures of rod-shaped colloidal nanoparticles in intricate geometries.We designed reactive chiral inks based on cellulose nanocrystal(CNC)suspensions and acrylamide monomers,enabling the chiral assembly at nano/microscale,beyond the resolution seen in printed materials.We employed a range of complementary techniques including Orthogonal Superposition rheometry and in situ rheo-optic measurements under steady shear rate conditions.These techniques help us to understand the nature of the nonlinear flow behavior of the chiral inks,and directly probe the flow-induced microstructural dynamics and phase transitions at constant shear rates,as well as their post-flow relaxation.Furthermore,we analyzed the photo-curing process to identify key parameters affecting gelation kinetics and structural integrity of the printed object within the supporting bath.These insights into the interplay between the chiral inks self-assembly dynamics,3D printing flow kinematics and photopolymerization kinetics provide a roadmap to direct the out-of-equilibrium arrangement of CNC particles in the 3D printed filaments,ranging from uniform nematic to 3D concentric chiral structures with controlled pitch length,as well as random orientation of chiral domains.Our biomimetic approach can pave the way for the creation of materials with superior mechanical properties or programable photonic responses that arise from 3D nano/microstructure and can be translated into larger scale 3D printed designs.

关 键 词：Directed chiral self-assembly Cellulose nanocrystals Bioinspired nanocomposite 3D printing RHEOLOGY 

分 类 号：TB383.1[一般工业技术—材料科学与工程] TP391.73[自动化与计算机技术—计算机应用技术]