PhD Proposal by Andrew J. Erwin

Event Details
  • Date/Time:
    • Tuesday December 5, 2017 - Wednesday December 6, 2017
      10:00 am - 11:59 am
  • Location: MoSE 1226
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Summary Sentence: Branched Functional Polymers in Hybrid Electrolytes: Responsive Nanomaterials for Controlled Ion Transport

Full Summary: No summary paragraph submitted.





Under the provisions of the regulations for the degree


on Tuesday, December 5, 2017

10:00 AM
in MoSE 1226


will be held the





Andrew J. Erwin


"Branched Functional Polymers in Hybrid Electrolytes: Responsive Nanomaterials for Controlled Ion Transport"


Committee Members:


Prof. Vladimir V. Tsukruk, Advisor, MSE

Prof. Alexei P. Sokolov, Co-advisor, CHEM/PHYS, ORNL/UT

Prof. Blair K. Brettmann, MSE

Prof. Alberto Fernandez-Nieves, PHYS

Prof. Zhiqun Lin, MSE

Prof. Paul S. Russo, MSE/CHEM




Polyelectrolytes and polymerized ionic liquids (PILs) are promising candidates for the design of ionically conductive media due to their viscoelasticity, robust chemical and thermal stability, controlled morphology, and single-ion conductivity. While the immobile, polymerized framework stabilizes the conductive media, prolongs its operational lifetime, and improves its safety relative to classical electrolytes, it invariably reduces ion mobility to unacceptable levels at ambient conditions. The proposed research addresses this issue by leveraging macromolecular architecture and functionality to mediate the interactions and self-assembly of hybrid electrolytes with improved ion conductivity and sustained mechanical stability. Branched polymers are attractive in this regard because they afford greater versatility in their local functional group densities, chain conformations, and counterion condensation. These compounds and their supramolecular nanostructures can then be exploited as heterogeneous colloidal building blocks in the hierarchical organization of compartmentalized polymer electrolyte materials with stimuli-responsive morphologies. The ultimate goal is to program the structure, free volume, local/percolating dynamics, and ionic association in order to control and direct charge transport.


Accordingly, the first task aims to unravel the role of star architecture and molecular weight on the organization and ion transport mechanisms of PIL electrolytes. Multivalent ions and plasticizers with high dielectric constant will be introduced to adjust arm conformations, morphology, charge delocalization, and ion conductivity. In the second task, hyperbranched oligomeric ionic liquids (HB-OILs) with different number and balance of terminal functional groups are combined with ionic liquids (ILs) in nonvolatile, thermoresponsive ionogels. Critical solution phase behavior will be identified and related to changes in phase-separated morphologies, glass transition temperatures, spatial confinement, nanoscale mechnical properties, and ion transport. Finally, multifunctional miktoarm and amphiphilic star graft block copolymers and their colloidal self-assembly as micelles/interpolyelectrolyte complexes are investigated in homogenous/thermoresponsive ionogel electrolytes. These studies will emphasize: (i) controlling the decoupling of ion motion from structural relaxations, (ii) facilitating synergistic interactions between different components for tunable ion dissociation, transference number, and mobility and (iii) generating internally phase-separated, percolating ionophilic channels with controlled chain conformations for the long-range, coordinated motion of ions. To this extent, branched polyelectrolytes and PILs with tunable chemistry, unique spatial/dynamic heterogeneity, and amplified intermolecular and surface interactions are ideal for the bottom-up design of responsive polymer electrolytes. Expanding polymer functionality and tailoring the structure-property relationships towards optimized mechanical characteristics, electrochemical/thermal stability, and fast single-ion conductivity in these multicomponent systems is anticipated to meet the pressing demands of electrolyte materials in emerging energy storage and conversion technologies.

Additional Information

In Campus Calendar

Graduate Studies

Invited Audience
Faculty/Staff, Public, Graduate students, Undergraduate students
Phd proposal
  • Created By: Tatianna Richardson
  • Workflow Status: Published
  • Created On: Nov 27, 2017 - 12:24pm
  • Last Updated: Nov 27, 2017 - 12:24pm