Session: 06-02 Micro/Nanofluidic Sytems, Techniques and Devices

Paper Number: 87758

87758 - Development of Nano- and Micro-Fluids Using Magnetic Poly(Ionic Liquid)-Surfactant Complexes for Stimuli Response 

This effort builds on prior ferrofluid studies, where iron and iron-cobalt oxide nanoparticles displayed enhanced magnetic properties in a magnetic field due to the ability of the nanoparticle magnetic poles to align.  Poly(ionic liquids) (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. The pendant ionic liquid monomer units imbue the polymer with favorable properties such as high ion conductivity, thermal and chemical stability, unique solubility, and functionality. PIL properties are highly dependent on their counterion, which can be easily exchanged to tailor their material properties.  Incorporation of metal halide counterions (FeCl₄^-, CoCl₄^-, 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 solubility, self-assembly, and stability in situ.  In this study, a PIL copolymer, poly(acrylamide-co-diallyl dimethylammonium chloride), which contains a quaternary ammonium PIL group and a comonomer capable of metal coordinating interactions, was used to form MPIL copolymers. This halide copolymer was complexed with Co²⁺ and Fe³⁺ metal halide salts to form magnetic polymers. The chemical properties of these polymers were studied in both the liquid and dry states as a function of metal salt concentration using FTIR, XPS, UV-vis, and Raman spectroscopies. Magnetic properties were examined using AC susceptibility and magnetometry.  The impact of metal ion(s), concentrations of the courterions, surfactant loading, and magnetic field were examined for these novel M-PIL systems and well-defined ferrofluids were used as comparative benchmark systems.

Presenting Author: Kayla Foley University of Arkansas