The effect of pulsed electric fields on the rheology and microstructure of chitosan-poly(vinyl alcohol) composites

Colloidal matrices of chitosan (CS) and poly(vinyl alcohol) (PVOH), 0.18 weight fraction CS (wiCS), were subjected to pulsed electric fields (PEF) at specific energy 95 - 465 kJ/kg. The influence of pH was examined at various pHs 4.1, 4.8 (control), 5.2, 5.6 and 6.1. The treated samples were subsequently analysed for particle size and size distributions, surface zeta potential and viscoelastic behaviour. PEF at specific energy ≥275 kJ/kg resulted in larger particles and a wider range of particle size distribution (PSD). The zeta potential decreased with increasing pH, which corresponded with an increase in particle size. High pH of the inter-mixed blends of CS and PVOH resulted in higher viscosity, but weaker intermolecular associations as depicted by the rapidly declining viscosity. These findings demonstrated the potentials of PEF in the microstructural modification of macromolecular systems.