Hydration Properties of Chemically Modified Phytoglycogen Nanoparticles

As a natural and sustainable biopolymer, phytoglycogen (PG) nanoparticles extracted from sweet corn are promising candidates for a wide range of applications.  We modified the particles by attaching charged chemical groups (both anionic and cationic), which produced distinctive changes to their physical properties.  Further changes were achieved through the addition of salts to tune the electrostatic interaction between particles. I will describe the hydration properties of PG nanoparticles that were modified using either anionic (carboxymethylation; CM-PG) or cationic (glycidyltrimethylammonium chloride; GTAC-PG) groups.  We used ellipsometry and attenuated total reflection infrared (ATR-IR) spectroscopy to probe changes in the swelling properties and network water structuring at relative humidity values ranging from 4 to 90%. We observed dramatic differences between the hydration properties of modified-PG and native PG particles, with significant changes produced by the addition of monovalent (NaCl) and divalent (CaCl₂) salts.  These studies demonstrate that chemical modification of PG nanoparticles can be used to create new nanomaterials with dramatically different physical properties for enhanced applications.