Next Article in Journal
Dielectric and Electro-Optic Effects in a Nematic Liquid Crystal Doped with h-BN Flakes
Next Article in Special Issue
From Equilibrium Liquid Crystal Formation and Kinetic Arrest to Photonic Bandgap Films Using Suspensions of Cellulose Nanocrystals
Previous Article in Journal
3D Numerical Analysis of the Asymmetric Three-Phase Line of Floating Zone for Silicon Crystal Growth
Previous Article in Special Issue
The Lyotropic Analog of the Polar SmC* Phase
Article

Flexible and Structural Coloured Composite Films from Cellulose Nanocrystals/Hydroxypropyl Cellulose Lyotropic Suspensions

i3N/CENIMAT, Department of Materials Science, NOVA School of Science and Technology, NOVA University Lisbon, Campus de Caparica, 2829-516 Caparica, Portugal
*
Author to whom correspondence should be addressed.
Crystals 2020, 10(2), 122; https://doi.org/10.3390/cryst10020122
Received: 3 January 2020 / Revised: 12 February 2020 / Accepted: 12 February 2020 / Published: 16 February 2020
(This article belongs to the Special Issue New Trends in Lyotropic Liquid Crystals)
Lyotropic colloidal aqueous suspensions of cellulose nanocrystals (CNCs) can, after solvent evaporation, retain their chiral nematic arrangement. As water is removed the pitch value of the suspension decreases and structural colour-generating films, which are mechanically brittle in nature, can be obtained. Increasing their flexibility while keeping the chiral nematic structure and biocompatible nature is a challenging task. However, if achievable, this will promote their use in new and interesting applications. In this study, we report on the addition of different amounts of hydroxypropyl cellulose (HPC) to CNCs suspension within the coexistence of the isotropic-anisotropic phases and infer the influence of this cellulosic derivative on the properties of the obtained solid films. It was possible to add 50 wt.% of HPC to a CNCs aqueous suspension (to obtain a 50/50 solids ratio) without disrupting the LC phase of CNCs and maintaining a left-handed helical structure in the obtained films. When 30 wt.% of HPC was added to the suspension of CNCs, a strong colouration in the film was still observed. This colour shifts to the near-infrared region as the HPC content in the colloidal suspension increases to 40 wt.% or 50 wt.% The all-cellulosic composite films present an increase in the maximum strain as the concentration of HPC increases, as shown by the bending experiments and an improvement in their thermal properties. View Full-Text
Keywords: liquid crystal; cellulose nanocrystals; hydroxypropyl cellulose; lyotropic; chiral nematic liquid crystal; cellulose nanocrystals; hydroxypropyl cellulose; lyotropic; chiral nematic
Show Figures

Figure 1

MDPI and ACS Style

Saraiva, D.V.; Chagas, R.; Abreu, B.M.d.; Gouveia, C.N.; Silva, P.E.S.; Godinho, M.H.; Fernandes, S.N. Flexible and Structural Coloured Composite Films from Cellulose Nanocrystals/Hydroxypropyl Cellulose Lyotropic Suspensions. Crystals 2020, 10, 122. https://doi.org/10.3390/cryst10020122

AMA Style

Saraiva DV, Chagas R, Abreu BMd, Gouveia CN, Silva PES, Godinho MH, Fernandes SN. Flexible and Structural Coloured Composite Films from Cellulose Nanocrystals/Hydroxypropyl Cellulose Lyotropic Suspensions. Crystals. 2020; 10(2):122. https://doi.org/10.3390/cryst10020122

Chicago/Turabian Style

Saraiva, Diogo V., Ricardo Chagas, Beatriz M.d. Abreu, Cláudia N. Gouveia, Pedro E.S. Silva, Maria H. Godinho, and Susete N. Fernandes 2020. "Flexible and Structural Coloured Composite Films from Cellulose Nanocrystals/Hydroxypropyl Cellulose Lyotropic Suspensions" Crystals 10, no. 2: 122. https://doi.org/10.3390/cryst10020122

Find Other Styles
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop