Particle size effects in colloidal gelatin particle suspensions

This paper describes the effects of simple shear flow on the formation and properties of colloidal gelatin particle suspensions. Microscopy and light scattering show that simple shear flow of a phase-separating gelatin–dextran mixture gave smaller particles with a narrower size distribution. Upon gelation due to a temperature decrease, the viscosity of the gelatin increased, which altered the coalescence and break-up behaviour of the particles formed. The small particles obtained by a high shear during processing aggregated into larger particle clusters, once particle solidified upon gelation. The particle size can be predicted using correlation with droplet break-up and coalescence considering the properties before gelation. The sizes of the clusters can be predicted with the coalescence behaviour using the properties after gelation. Clusters originating from small particles resist more deformation, resulting in pronounced rheological effects (e.g. increase viscosity, increased strain softening point).