Multiscale Transport and Dynamics in Ion-Dense Organic Electrolytes and Copolymer Micelles

dc.contributor.authorKidd, Bryce Edwinen
dc.contributor.committeechairMadsen, Louis A.en
dc.contributor.committeememberTroya, Diegoen
dc.contributor.committeememberMorris, John R.en
dc.contributor.committeememberGibson, Harry W.en
dc.contributor.departmentChemistryen
dc.date.accessioned2018-03-18T06:00:28Zen
dc.date.available2018-03-18T06:00:28Zen
dc.date.issued2016-09-23en
dc.description.abstractUnderstanding molecular and ion dynamics in soft materials used for fuel cell, battery, and drug delivery vehicle applications on multiple time and length scales provides critical information for the development of next generation materials. In this dissertation, new insights into transport and kinetic processes such as diffusion coefficients, translational activation energies (Ea), and rate constants for molecular exchange, as well as how these processes depend on material chemistry and morphology are shown. This dissertation also aims to serve as a guide for material scientists wanting to expand their research capabilities via nuclear magnetic resonance (NMR) techniques. By employing variable temperature pulsed-field-gradient (PFG) NMR diffusometry, which can probe molecular transport over nm – μm length scales, I first explore transport and morphology on a series of ion-conducting materials: an organic ionic plastic crystal, a proton-exchange membrane, and a polymer-gel electrolyte. These studies show the dependencies of small molecule and ion transport on modulations to material parameters, including thermal or magnetic treatment, water content, and/or crosslink density. I discuss the fundamental significance of the length scale over which translational Ea reports on these systems (~ 1 nm) and the resulting implications for using the Arrhenius equation parameters to understand and rationally design new ion-conductors. Next, I describe how NMR spectroscopy can be utilized to investigate the effect of loading a small molecule into the core of a spherical block copolymer micelle (to mimic, e.g., drug loading) on the hydrodynamic radius (rH) and polymer chain dynamics. In particular, I present spin-lattice relaxation (T1) results that directly measure single chain exchange rate kexch between micelles and diffusion results that inform on the unimer exchange mechanism. These convenient NMR methods thus offer an economical alternative (or complement) to time-resolved small angle neutron scattering (TR-SANS).en
dc.description.degreePh. D.en
dc.format.mediumETDen
dc.identifier.othervt_gsexam:8923en
dc.identifier.urihttp://hdl.handle.net/10919/82525en
dc.publisherVirginia Techen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectorganic ionic plastic crystalen
dc.subjectpolymer-gel electrolyteen
dc.subjection-conducting membraneen
dc.subjectcopolymer micelleen
dc.subjectNMRen
dc.subjectself-diffusionen
dc.subjectT1/T2 relaxationen
dc.subjectStokes-Einstein relationen
dc.titleMultiscale Transport and Dynamics in Ion-Dense Organic Electrolytes and Copolymer Micellesen
dc.typeDissertationen
thesis.degree.disciplineChemistryen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.leveldoctoralen
thesis.degree.namePh. D.en

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