Date of Award

Spring 2-28-2019

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

First Advisor

Douglas L. Gin

Second Advisor

Wei Zhang

Third Advisor

Steven M. George

Fourth Advisor

David M. Walba

Fifth Advisor

Yifu Ding

Abstract

Chemical warfare agents (CWAs) and toxic industrial chemicals (TICs) are organic compounds that, when released, pose hazards to civilians and first responders. Several technologies exist to decontaminate materials exposed to these compounds, but their physical limitations prevent them from being effective for treating certain types of CWA- or TIC-contacted substrates. Current decontamination technologies cannot be applied to complex or vertical surfaces, which risks long-term exposure to the hazardous organic compounds if they cannot be extracted from the substrate surface or interior. Ionic liquid (IL) gels are a relatively new type of decontamination material that can be applied to complex substrates due to their mechanical strength, non-volatility, and structural modularity. Previous work has shown that IL gels that adopt solid-like morphologies via non-covalent intermolecular forces or polymer networks are effective for removing CWA and TIC simulants from contacted substrates.

This thesis discusses the preparation of new IL-based gel systems based on ammonium ILs that can be cured in situ using step-growth polymerization to form IL polymer network/free IL composites. The first-generation materials developed were polymerized ionic liquid (PIL)/IL composites containing cross-linked polyurethane linkages. These coatings proved to be not only thermally and electrochemically stable, but they could also be applied in their monomeric mixture form to substrates contacted by a TIC simulant and subsequently cured into solid, flexible films. The coatings were found to be effective vapor barrier materials for use on rubber and painted steel. In order to prevent the soak-in of these coatings on porous substrates, a series of reactive ammonium IL prepolymers that could also be cured in situ was prepared using RAFT polymerization. The reactive IL prepolymer/IL mixtures could be applied to and cured on porous wood and ceramic with minimal soak-in, and were found to prevent vapor release of the TIC simulant and extract the liquid simulant from the interior of the substrates. Finally, several novel ammonium ILs containing organosulfonate and organophosphonate anions were synthesized and combined with commercial polymers to form IL physical gels for potential hazard mitigation use on human skin. Preliminary studies investigated their absorption into a synthetic skin membrane, Strat-MTM.

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