| Title: |
Discrete Cellulose Nanocrystals Photonic Films with Periodic Dual Circular Dichroism and Infra-Red Reflectance |
| Authors: |
Dimitrov, Botyo Antoniev |
| Contributors: |
Tsukruk, Vladimir V.; Materials Science and Engineering; Shofner, Meisha; Cai, Wenshan |
| Publisher Information: |
Georgia Institute of Technology |
| Publication Year: |
2025 |
| Collection: |
Georgia Institute of Technology: SMARTech - Scholarly Materials and Research at Georgia Tech |
| Subject Terms: |
Cellulose nanocrystals; 3D shear printing; dual helicity; NIR reflectance; active circular polarization; harmonic circular dichroism; twisted dielectric mirror |
| Description: |
Daylight and thermal management have an increasing importance due to ongoing efforts to conserve energy consumption. Current commercially available absorption-based technologies affect the visible range of the spectrum. At the same time, near-infrared (NIR) reflecting materials, such as chiral nematic liquid crystals, are achieved by crosslinking stabilization of synthetic organic mesogens, posing a scalability and cost challenge. It is of interest to develop a lightweight and sustainable material that has good visible transmittance, limits NIR appearance, and is based on abundant and renewable sources manufactured via an accessible manufacturing method. Additionally, there is a growing demand for materials with engineered circular dichroism for various photonic applications sensitive to circularly polarized light (CPL). In this work, twisted helical cellulose nanocrystal (CNC) films with dual CPL and NIR reflectance properties are fabricated via a facile blade coating 3D printing method. The printed films show both left and right-handed (LH, RH) CPL reflectance/transmittance, as opposed to natural homochiral CNC films. It is demonstrated that by manipulation of the process parameters of the discrete twisted helical organization– twisting angle and anisotropic block thickness – distinct CD patterns and transmittance could be achieved. We further show the produced films could be treated as hybrid metamaterials swinging between two extremes – a 1D photonic crystal aka Bragg stacks and a conventional continuous chiral nematic film. The films exhibit both reflectance and CD peaks yielding a pre-programmed material with dual chiroptical properties as well as an achiral film with NIR reflectance. We suggest the potential of the larger-scale printed structuring of unique cellulose nanomaterials for CPL-sensitive photonic, thermal, and energy management applications. In order to improve the optical performance, hybrid MXene-CNC films are investigated next. 1D Photonic Crystals (PC) with alternating MXene and CNC layers ... |
| Document Type: |
thesis |
| File Description: |
application/pdf |
| Language: |
English |
| Relation: |
https://hdl.handle.net/1853/77747 |
| Availability: |
https://hdl.handle.net/1853/77747 |
| Accession Number: |
edsbas.CD435828 |
| Database: |
BASE |