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THE SCHOOL OF MATERIALS SCIENCE AND ENGINEERING
GEORGIA INSTITUTE OF TECHNOLOGY
Under the provisions of the regulations for the degree
DOCTOR OF PHILOSOPHY
on Tuesday, October 29, 2019
2:00 PM
in MoSE 3201A
will be held the
DISSERTATION DEFENSE
for
Zewei Wang
“Rational Design of Architectured Amphiphilic Block Copolymers and Polymer-Ligated Nanocrystals for Energy Storage and Drug Delivery”
Committee Members:
Prof. Zhiqun Lin, Advisor, MSE
Prof. Vladimir Tsukruk, MSE
Prof. Dong Qin, MSE/CHBE
Prof. Younan Xia, CHBE
Prof. Yulin Deng, CHBE
Abstract:
Three architectured amphiphilic block copolymers (star-shaped, bottlebrush-shaped, and Janus star- shaped) are rationally designed and synthesized by capitalizing on multifunctional glucose-based biomolecules, either β-cyclodextrin (β-CD) as the core (for star- and Janus star-shaped) or cellulose as the backbone (for bottlebrush-shaped). These architectured amphiphilic block copolymers are synthesized through atom transfer radical polymerization and/or reversible addition-fragmentation chain-transfer polymerization, thereby possessing precisely controlled molecular weight and low polydispersity (PDI). These characteristics render them perfect polymeric nanoreactors for the synthesis of plain nanoparticles, nanorods, and spherical Janus nanoparticles. Specifically, first, poly(styrene-co-acrylonitrile)-ligated MFe2O4 nanoparticles crafted from star-shaped block copolymer nanoreactors display superior rate and cycling performance in lithium/sodium ion batteries when applied as anode. The surface poly(styrene-co-acrylonitrile) ligands can not only transport Li+ but also act as efficient physical barrier to prevent phase coarsening. Second, a robust crosslinking strategy via UV-initiated azide homocoupling is developed to readily convert azide-functionalized bottlebrush-shaped block copolymers into polymeric cocoons, exhibiting 3-fold encapsulation, 3-fold release time, and modulated release rate compared with non-crosslinked counterpart. Additionally, CsPbBr3 nanocrystals synthesized from the bottlebrush-shaped block copolymer nanoreactors possess much higher water, UV, and thermal stabilities in comparison to conventional aliphatic ligand-capped CsPbBr3 due to permanent ligation of polymer hairs as a dense protection layer. Finally, Janus star-shaped block copolymers are rationally synthesized which can readily structure-direct the growth of strictly biphasic Janus nanoparticles.
