Dissertation/Thesis Abstract

Magnetic Alignment and Charge Transport Improvement in Functional Soft Materials
by Majewski, Pawel W., Ph.D., Yale University, 2013, 228; 3578414
Abstract (Summary)

The realization of nanostructured functional materials by self-assembly in polymers and polymer nanocomposites is adversely affected by persisting structural defects which greatly diminish the performance of the material. The use of magnetic fields to impose long-range order is investigated in three distinct systems - ion-conducting block copolymers, semiconducting nanowire-polymer composites and lyotropic surfactant mesophases. The alignment process is quantitatively studied with X-ray scattering and microscopic methods. Time and temperature resolved data collected in situ during the magnetic experiments provide an insight into the thermodynamic and kinetic aspects of the process. These data together with simultaneous electrical conductivity measurements allow relating fundamental structural properties (e.g., morphology and long-range order) to transport properties (i.e., conductivity). In particular, it is demonstrated that magnetic fields offer a viable route for improvement of electric conductivity in these systems. More than an order of magnitude increase in conductivity is recorded in magnetically-annealed materials. The resulting aligned nanostructured systems are attractive for ordered solid polymer electrolyte membranes, heterojunction photovoltaic devices and generally help to understand charge transport mechanisms in anisotropic heterogeneous systems.

Indexing (document details)
Advisor: Osuji, Chinedum
School: Yale University
School Location: United States -- Connecticut
Source: DAI-B 75/05(E), Dissertation Abstracts International
Subjects: Polymer chemistry, Chemical engineering, Materials science
Keywords: Black copolymers, Ionic conductivity, Magnetic alignment, SAXS Xray scattering, Surfectants
Publication Number: 3578414
ISBN: 978-1-303-71594-5
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