We will discuss how particles with anisotropic shape and engineered properties can be synthesized and applied in the formation of Pickering foams and emulsions with novel functionality. These particles are synthesized by 'liquid nanofabrication' in biphase liquids under shear. We demonstrated earlier the large-scale fabrication of polymer microrods and reported how they act as superstabilizers of foams and emulsions by forming rigid adsorption shells around the bubbles or droplets. The method allowed synthesizing HMC and lignin particles that can enrich Pickering foams and emulsions with additional features such as color, specific rheological response, stability against drying, controlled destabilization and controlled release. We will present means of making strongly and selectively colored foams by co-precipitating HMC with dye. We will also demonstrate how the inclusion of magnetic particles in the HMC matrix allows making 'magneto-Pickering' foams, which exhibit excellent stability in the absence of a magnetic field, but can be destroyed quickly and on demand with the application of a threshold field. The rheological characteristics and collapse behavior of these foams can be correlated to the liquid fraction as well as the concentration of magnetic particles in the lamellae. The use of lignin particles as foam stabilizers allows making stable foams with gel-like films between the bubbles. These novel systems provide fundamental insights on the properties of Pickering foams, and can find applications in processes requiring immediate non-contact defoaming.

Functional responsive foams stabilized with particles of engineered shape and structure

245th National Meeting (2013)

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