Ilpo Niskanen, Terhi Suopajärvi, Henrikki Liimatainen, Tapio Fabritius, Rauno Heikkilä, Göran Thungström, Determining the complex refractive index of cellulose nanocrystals by combination of Beer-Lambert and immersion matching methods, Journal of Quantitative Spectroscopy and Radiative Transfer, Volume 235, 2019, Pages 1-6, ISSN 0022-4073, https://doi.org/10.1016/j.jqsrt.2019.06.023
Determining the complex refractive index of cellulose nanocrystals by combination of Beer-Lambert and immersion matching methods
|Author:||Niskanen, Ilpo1,2; Suopajärvi, Terhi3; Liimatainen, Henrikki3;|
1Faculty of Technology, Structures and Construction Technology, University of Oulu, P.O. Box 4300, FI-90014 Oulu, Finland
2Department of Electronics Design, Mid Sweden University, Holmgatan 10, SE-85170 Sundsvall, Sweden
3Faculty of Technology, Fibre and Particle Engineering, University of Oulu, P.O. Box 4300, FI-90014 Oulu, Finland
4Faculty of Information Technology and Electrical Engineering, Optoelectronics and Measurement Techniques Research Unit, University of Oulu, P.O. Box 4300, FI-90014 Oulu, Finland
|Persistent link:|| http://urn.fi/urn:nbn:fi-fe2019091928959
|Publish Date:|| 2021-06-19
Nanocelluloses have received significant interest due to their unique structural, mechanical, and optical properties. Nanocellulose refractive indices can be used to indicate many crucial characteristics, such as crystallinity, transparency, and purity. Thus, accurate measurement is important. This study describes a new method to determine the wavelength dependent complex refractive index of cellulose nanocrystals (CNCs) by the measurement of light transmittance with a spectrophotometer. The data analysis is based on a combination of the Beer-Lambert and immersion liquid matching equations. The immersion liquid method’s main advantage is that it is independent of particle shape and size. Moreover, the measurement is easy and relatively quick to perform. The present procedure is not restricted to the nanocellulose and could potentially be applied to other nanomaterials, such as hyphenate nanoparticle-based, lignin nanoparticles, nanopigments, biological entities, structural elements of dielectric metamaterials, and nanoparticle-based composites.
Journal of quantitative spectroscopy & radiative transfer
|Pages:||1 - 6|
|Type of Publication:||
A1 Journal article – refereed
|Field of Science:||
114 Physical sciences
213 Electronic, automation and communications engineering, electronics
216 Materials engineering
We gratefully acknowledge funding from the Knowledge Foundation of Sweden (2150361).
© 2019 Elsevier B.V. All rights reserved. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/.