Fabrication of the durable low refractive index thin film with chitin-nanofiber by LBL method

C Tanaka,S Shiratori,M Goldmann,P Guenoun

doi:10.1051/matecconf/20130405006

Abstract

Durable low refractive index thin films with anti-reflection properties were successfully fabricated using chitin nanofibers (CHINF) obtained from crab shell. The low refractive index film was achieved by forming porous thin films; the porosity was produced by increasing the number of airspaces inside the membrane. The layer-by-layer (LBL) method was used to achieve the effective stacking of the CHINF. The influence of surface structure and refractive index under changes in the solution pH was investigated using scanning electron microscopy and ellipsometry. Transmittance of the fabricated film is 4.1 % higher than that of a glass substrate and refractive index film of that is 1.29. The films had abrasion resistance and antifogging properties because of the high mechanical strength and hydrophilicity of chitin. We believe this LBL film using CHINF is a promising candidate material to overcome the durability problems associated with optical thin films.

Highlights

A Chitin nanofibers (CHINF) have attracted much attention because of their high mechanical strength and biocompatibility
The shells of crustaceans are expected to be useful for materials applications, because they are made from mineral salts, protein, and chitin; it is known that mineral salts can be removed using HCl, and proteins can be removed using NaOH.[1]
The chitin nanofibers (CHINF) surface is transformed from chitin to chitosan by deacetylation, which results in a positive charge on the CHINF, due to the presence of amine groups

Summary

Introduction

A Chitin nanofibers (CHINF) have attracted much attention because of their high mechanical strength and biocompatibility. Crabs are crustaceans with an exoskeleton that forms like twisted plywood and has high tensile strength and bendability.[1,2] The shells of crustaceans are expected to be useful for materials applications, because they are made from mineral salts, protein, and chitin; it is known that mineral salts can be removed using HCl, and proteins can be removed using NaOH.[1] if only these procedures are used, the surfaces of CHINF do not have any electrostatic charge. The CHINF surface is transformed from chitin to chitosan by deacetylation, which results in a positive charge on the CHINF, due to the presence of amine groups. The transparency of the solution changes depending on the deacetylation time.[3]

Methods

Results

Conclusion