Effect of the Particle Size on the Rheology of Gellan Gum Micro Gel

Focusing on the particle size of gellan gum microgel fluid dispersion, we found that even with the same composition, the appearance and rheological characteristics of microgel fluid dispersion were different depending on the difference of particle size. Comparison among rheological characteristics indicated that the greater the particle size of microgel was, the larger the yield stress and shear stress during flowage were and that there was an appropriate correlation (r=0.97) between the particle size of microgel and the yield stress of fluid dispersion. It was observed that among microgel fluid dispersion samples having the same particle size, the less concentration of calcium ions added as crosslinker for double helix they had, the greater shear stress they showed. We considered it as an influence of interaction among microgel particles. We found that the control of the particle size of microgel fluid dispersion and the calcium ion concentration was effective as a method of controlling the properties of microgel fluid dispersion. Microgel particles with smaller size decrease the yield stress of fluid dispersion, deteriorating the dispersion stability of dispersoid. However, by including the dispersoid in microgel particles, we could prepare a product providing a compatibility between the product appearance and stability.