Discipline: Technology and Engineering
Subcategory: Materials Science
Room: Park Tower 8216
Bobby Haney - Florida A&M University
Co-Author(s): Subramanian Ramakrishnan
Pickering emulsions are critical to systems where encapsulation of an oil or water phase in an immiscible medium is required. These coated emulsions can harbor oils in water or even water in oils. While hard particles are traditionally used, microgel particles have also been used as emulsion stabilizers. These polymer colloids differ from rigid particles in many ways. When compared to microgels, colloidal particles are lyophobic, meaning they need surface modification to be preferably “wet” by a solvent. Microgels can be made to be lyophilic, having an attraction to the solvent that swells them. Microgels are cross-linked polymer networks that absorb and desorb solvents where the type of solvent used to swell a microgel can be tailored during particle synthesis. Using a Polydimethylsiloxane microfluidic device, via soft lithography, the flow streams of two separate polymer solutions, polyethylene and polypropylene, were brought into contact to form Janus droplets. The individual droplets were then exposed to UV light to induce cross-linking via photo-polymerization to form monodispersed microgel particles with sectioned hydrophilic and hydrophobic sides. In crosslinking these two systems together, we form single particles that have one side capable of absorbing water and another with the ability to absorb and desorb organic solvents. The microgel particles possess two separate and distinctly different sides crosslinked together at one interface. These particles were used to make stable water in oil and oil in water Pickering emulsions by mixing them in water and toluene dispersions. By varying the ratio of polymer to monomer-crosslinker in each polymer solution, swelling of the gelled sides of the resulting amphiphilic microgels is controlled. Microgel particles of higher crosslink density swelled less than those of lower density at every mixture temperature. These amphiphilic microgels pose as interesting tools in stabilizing emulsion droplets for cosmetic, pharmacy, and petroleum industries.
Funder Acknowledgement(s): FAMU CREST: Center for Complex Materials Design (CoMan D) for Multidimensional Additive Processing [NSF#1735968] HBCU Title III part B section 323
Faculty Advisor: Subramanian Ramakrishnan, firstname.lastname@example.org
Role: This research was conducted entirely by myself. Other authors on the work were responsible for guidance, ideas, funding, and materials.