(436b) In-Situ Characterization of Cellulose Nanocrystals Via Static Light Scattering

This paper presents a method to measure the three dimensions of cellulose nanocrystals (CNC) in suspension, without drying and with minimal sample preparation.  Debye’s expansion of the form factor has been used for decades to obtain the radius of gyration (second moment of distances within a particle) of polymers and particles in a liquid medium.  Even though the radius of gyration is a useful indication of size, it does not provide any information about the shape of the particles, or macromolecules, in suspension.  Herein we extended Debye’s expansion to obtain analytical expressions for the fourth and sixth moments that are valid for all nanoparticle shapes.  The latter expressions can be used to obtain information about the aspect ratio of the nanoparticles in suspension.  If a shape is assumed it is easy to calculate the respective dimensions.  The measured CNC dimensions (6.4 x 28 x 152 nm) are in close agreement with atomic force microscopy measurements. This methodology is expected to be applicable to particles of complex shapes and bio-based macromolecules; and it can be extended to other scattering techniques.

Reference

1. Ureña-Benavides, E.E.; Kitchens, C.L. Static Light Scattering of Triaxial Nanoparticle Suspensions in the Rayleigh-Gans-Debye Regime: Application to Cellulose Nanocrystals. RSC Advances 2012, 2, 1096 – 1105.