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Document Type

Open Access Dissertation

Degree Name

Doctor of Philosophy (PhD)

Degree Program

Polymer Science and Engineering

Year Degree Awarded

2015

Month Degree Awarded

February

First Advisor

Prof. Todd Emrick

Second Advisor

Prof. Alfred J. Crosby

Third Advisor

Prof. Anthony D. Dinsmore

Fourth Advisor

Prof. Ryan C. Hayward

Subject Categories

Biology and Biomimetic Materials | Materials Chemistry | Nanoscience and Nanotechnology | Organic Chemistry | Polymer and Organic Materials | Polymer Chemistry | Polymer Science | Semiconductor and Optical Materials

Abstract

Advances in the synthetic strategies of engineered nanomaterials, multifunctional molecules and polymers have opened pathways for the development of functional nanomaterials having unique optoelectronic, mechanical, and biological properties. By designing the chemistry of surface ligands, the organic interface of nanoparticles, one can further the versatility and utilization of engineered nanomaterials, opening pathways for breakthroughs in sensing, catalysis, and delivery using nanomaterials.

This thesis describes the synthesis and characterization of small molecule and polymer ligand functionalized inorganic nanoparticles (e.g., metal, semiconducting). Embedding specific chemical functionality into the ligand periphery of nanoparticles enables the resulting functional nanoparticles to react selectively with amine function- alized materials, crosslink into robust and functional structures, and exhibit excellent non-fouling properties and biocompatibility.

Chapter 1 presents an introduction to nanoparticle building blocks, the synthesis of their components (nanoparticle and surface ligands), and a brief review of relevant literature.

Chapter 2 describes a versatile method of covalent inter-nanoparticle coupling using pentafluorophenyl ester functionalized nanoparticles (PFP-NP). PFP-NPs readily attached to a wide variety of amine functionalized NPs. PFP-NP grafting altered the solubility of other NPs, and selectively “turned off” the fluorescence of amine functionalized quantum dots (QDs) in a mixture of functional and non-functional QDs.

Chapter 3 describes a rapid fabrication of conductive nanoparticle (NP) ribbons from hydrophobic gold nanoparticles using evaporative self-assembly. Well-defined Au NP ribbons were obtained by reducing the ligand density, adopting one phase NP synthesis, and narrowing the size dispersity of Au NPs. The conductivity of NP ribbons was increased by adjustment of ligand chemistry while dramatic improvement in conductivity was observed after thermal sintering in the presence of polymer additives.

Chapters 4 and 5 describe the preparation of photocrosslinkable nanomaterials to form robust, precise nanostructures. Photocrosslinkable NPs were prepared to give ribbons and grids that were floated off substrates for further structural manipulation. Molding photocrosslinkable NPs in a perfluorinated elastomer template opened pathways to prepare geometrically precise NP wires, diblock NP wires and Janus NP disks.

Chapter 6 highlights the preparation of zwitterionic polymer covered nanorods and nanoparticles (PMPC-NR, PMPC-NP) that are highly stable, non-fouling and biocompatible. The presence of multiple bidentate comonomers along the copolymer backbone allows for total removal of NP native ligands and impart the NPs with high stability and exceptional aqueous solubility. PMPC-Au NR did not foul any substrate, and exhibited non-cytotoxicity in the presence of both human ovarian cancer cells and normal fibroblast cells. In vivo studies of PMPC-NP (pulmonary toxicity test on laboratory rats) confirmed the non-cytotoxicity and high biocompatibility of PMPC functionalized nanoscale particles.

Chapter 7 summarizes the thesis and presents a brief future outlook, while de- tailed experimental procedures and supporting informations are described in Chapter 8. A recent work on self-immolative crosslinkers for disassembling nanostructures is described in the appendix.

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