Natasha Castellanos

M.S., Chemical Engineering, 2018
North Carolina State University

B.S., Chemistry and Mathematics, 2016
Salem College

Research Focus: Magnetically Responsive and Self-Repairing Gels

Previous research in our group demonstrated successful capillary binding as well as self-repairing properties in a nanoparticle/water/ lipid system of filaments. The focus of my research is capillary force and magnetic force gelation based on these findings. The control of the capillary forces and magnetic interactions can be used to form new smart gel systems. Silicone oil microbeads are dispersed in aqueous medium and coated by an immiscible, fatty acid secondary liquid. The secondary liquid can selectively condense onto the beads surfaces and form liquid capillary bridges between them, thus leading to gelation. The physical properties of the gel structures formed by the capillary binding of particles depend on the bridge fluidity, type, and lipid composition. The systems that we investigate also contain magnetically responsive nanoparticles. We are synthesizing three types of such Magnetically Responsive Capillary Gels (MRCGs). In MRCG Type 1 the nanoparticles (NPs) are dispersed in the liquid phase. MRCG Type 2 is constituted of elastomer microspheres with internally embedded NPs. Similarly, MRCG Type 3 is composed of elastomer microspheres with embedded NPs arranged in filaments. These chain-containing microspheres could have a permanently embedded dipole moment.   We are characterizing these gels in terms of yield stress, rheology, magnetic response, and ability to self-heal upon magnetic field application. These data are correlated to the MRCG’s structure and response. These gels have the potential to be used in the formulation and testing of new classes of soft, responsive, and multifunctional matter.