(4bs) "Smart" Foams As Templates for Catalysts and Biomaterials

Aqueous foams can find many applications ranging from cosmetics and food formulation to various separation processes. My work to date focuses on the development of novel ‘smart’ foam systems, which can be manipulated using a number of external stimuli – including magnetic fields and light irradiation. Such systems can be utilized in their hydrated state or can be freeze-dried and utilized in the form of solid materials. They have potential applications in water remediation processes for efficient collection of contaminants, as well as in the controlled delivery of a substance trapped within the matrix of the foam. During my PhD study in the group of Prof. Orlin Velev, I have characterized how the variation of system parameters (i.e. stabilizer concentration, responsive material content, water content) can affect the viscoelastic properties of ‘smart’ Pickering foams; and, how this in turn affects the mechanisms by which the samples respond to an applied external stimulus. We used this information to develop models describing the mechanism of foam collapse by either bubble expulsion from the foam matrix or by thin film rupture, depending on the water content in the foam. I have also gained expertise in the formulation of various types of Pickering foams stabilized by naturally derived materials (such as cellulose and lignin), as well as in characterizing the physics behind foam evolution processes.

The fundamental knowledge from studying Pickering foams can be applied to the development of novel porous materials for catalysis and cell scaffolds from different types of particle-stabilized foams (stimuli responsive, nutrient releasing, degradable, etc.). The synthesis of these materials from Pickering foams requires only a few simple steps - foam generation through high shear homogenization at room temperature, and curing or freeze-drying to obtain solid foam. Novel materials can be easily fabricated via foam templating or emulsifying particles or mixtures of particles of a certain chemical nature. One can control the pore sizes and lamella thicknesses in the resulting materials by tuning the formulation of the prefoamed suspension.