Nature has developed an array of mechanisms and structures that are necessary for survival. They allow biological systems to fly, eat, survive harsh intertidal zones, walk on vertical surfaces, and many other processes. Not only are the abilities to perform these activities impressive, but their synthesis is impressive from a materials science stand point. The integration and implementation of the mechanisms and structures happens under mild reaction conditions: ambient temperature, atmospheric pressure, and in the presence of water and oxygen. Studying nature has proven to be an enticing inspiration for developing new materials.
In this work we focus on energy dissipation mechanisms found on nature for new polymeric materials. The mechanisms of interest are gradients, hierarchical structures and metal-ion coordination, which can be used to improve the toughness of materials. These mechanisms are applied to polyurethane foams and to a thiol-ene based network. The most promising results come from the integration of metal-ion complexation into a thiol-ene network. We were able to create a tunable network for improved stiffness, toughness, and breaking strain.
Additionally, it is useful to understand the chemistry of prevalent moieties found in nature. Extensive biological cross-linking for hardening is done using catechol and quinone functionalities. Chemoselective addition of organometallic reagents to 3-benzyloxy-1,2-o-quinone are described. Various nucleophiles are shown to undergo selective 1,2-addition, 1,4-addition, and etherification. Selective 1,2-additions provide stable, non-dimerizing o-quinols as a novel alternative to oxidative dearomatization.
|Advisor:||Stucky, Galen D.|
|Commitee:||Bazan, Guillermo C., Hawker, Craig J., Waite, J. Herbert|
|School:||University of California, Santa Barbara|
|School Location:||United States -- California|
|Source:||DAI-B 74/06(E), Dissertation Abstracts International|
|Subjects:||Biochemistry, Materials science|
|Keywords:||Bio-inspired, Energy dissipation, Polyurethane, Quinone, Thiol-ene|
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