DEVELOPMENT OF NANO- AND MICRO-FLUIDS USING MAGNETIC POLY(IONIC LIQUID)SURFACTANT COMPLEXES FOR STIMULI RESPONSE

Poly(ionic liquid) (PILs) are a rapidly growing subclass of polyelectrolyte which combines the diverse functionality of ionic liquids with the mechanical integrity, processability, and macromolecular design of polymeric systems. PIL properties are highly dependent on their counterion, which can be easily exchanged to tailor their material properties. Incorporation of metal halide counterions (FeCl4-, CoCl42-, etc.) into the PIL structure results in magnetically responsive metal-salt composites known as magnetic-PILs (MPILs). MPILs are predominately formed through electrostatic binding with anionic metal complexes typically resulting in paramagnetic properties at room temperature. The engineering properties and the ability to effectively apply these materials-is dependent on not only the chemical structure, but the nanostructure, co-materials, self-assembly, and stability in situ. In this study, a PIL copolymer, poly(acrylamide-co-diallyl dimethylammonium chloride), containing a quaternary ammonium PIL group and a comonomer capable of metal coordinating interactions, was combined with sodium dodecyl sulfate surfactant and cobalt (II) chloride salts to form magnetic polyelectrolyte-surfactant complexes. The self-assembly of these complexes was studied as a function of surfactant concentration through DLS, Zeta potential, and TEM characterizations. The magnetic properties were examined using AC susceptibility. The impact of the metal ion(s) and magnetic field on nanostructure alignment and film formation were also investigated through optical microscopy, GISAXS, and AFM imaging. Results were compared to well-defined ferrofluids as a comparative benchmark.