Chiral Nematic Cellulose Nanocrystal Films Cooperated with Amino Acids for Tunable Optical Properties.

Xiao Xiao,Jianfeng Ma,Jie Chen,Jiaqi Guo,Zhe Ling,Jianbin Huang,Zhi Jin

doi:10.3390/polym13244389

Abstract

The exploration of functional materials relies greatly on the understanding of material structures and nanotechnologies. In the present work, chiral nematic cellulose nanocrystal (CNC) films were prepared by incorporation with four types of amino acids (AAs, glycine, histidine, phenylalanine, and serine) via evaporation-induced self-assembly. The films present ideal iridescence and birefringence that can be tuned by the amount of AAs added. The intercalation of AAs enlarged the pitch values, contributing to the red-shift trend of the reflective wavelength. Among the AAs, serine presented the most compatible intercalation into cellulose crystals. Interestingly, histidine and phenylalanine composite films showed high shielding capabilities of UV light in diverse wavelength regions, exhibiting multi-optical functions. The sustainable preparation of chiral nematic CNC films may provide new strategies for materials production from biocompatible lignocellulose.

Highlights

Cellulose is one of the most abundant organic materials in the biosphere
cellulose nanocrystal (CNC) suspensions can selfassemble into chiral nematic phases at critical colloidal concentration [10]
CNC suspensions were mixed with amino acids (AA) at different proportions

Summary

Introduction

With a linear polysaccharide linked by β-1,4-glycosidic bonds of D-glucose, cellulose presents extremely high potential in bioconversion and the preparation of functional polymer materials [1,2,3]. Cellulose nanocrystals (CNCs) are existing domains of cellulose polymers and can be separated via hydrolysis or enzymatic hydrolysis from the distinctive two-phase structure containing ordered crystalline and amorphous parts [4,5,6]. CNC suspensions can selfassemble into chiral nematic phases at critical colloidal concentration [10]. The left-handed nematic phase can be further used for solid film preparation. As green and advanced multi-functional nanomaterials, CNC-based iridescent films have attracted great attention among researchers [13]

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Results

Conclusion