Oil-continuous capillary-based suspensions of zein particles

We investigate the sedimentation and flow behavior of dispersions of granular zein particles dispersed in oil, in the absence or presence of an immiscible fluid: water. Sedimentation experiments indicate that zein particles settle similarly to a hard-sphere system reaching a maximum packing fraction of ~0.4. Their viscosity can be described by hard-sphere phenomenological theories. When water is added, the viscosity of the system increases several orders of magnitude, forming a gel-like system. Its rheology is influenced by the increase of the effective volume fraction of the particles, and their bonding via capillary interactions.