Determining the complex refractive index of cellulose nanocrystals by combination of Beer-Lambert and immersion matching methods

• 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. 

Subject headings

TEKNIK OCH TEKNOLOGIER  -- Elektroteknik och elektronik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Electrical Engineering, Electronic Engineering, Information Engineering (hsv//eng)

Keyword

Beer-Lambert

Cellulose nanocrystals

Complex refractive index

Immersion matching method

Spectroscopy

Cellulose

Cellulose derivatives

Crystallinity

Nanocellulose

Nanocrystals

Nanoparticles

Particle size analysis

Accurate measurement

Cellulose nano-crystals

Cellulose nanocrystal (CNCs)

Immersion liquid methods

Matching methods

Particle shape and size

Refractive index

Publication and Content Type

ref (subject category)

art (subject category)