Date of Award

12-2012

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Legacy Department

Materials Science and Engineering

Advisor

Ke, Puchun

Committee Member

Ballato , John M.

Committee Member

Mefford , Thompson O.

Committee Member

Ellison , Michael S.

Abstract

Recent innovations and growth of nanotechnology have spurred exciting technological and commercial developments of nanomaterails. Their appealing physical and physicochemical properties offer great opportunities in biological and environmental applications, while in the meantime may compromise human health and environmental sustainability through either unintentional exposure or intentional discharge.
Accordingly, this dissertation exploits the physicochemical behavior of soft dendritic polymers for environmental remediation and condensed nano ZnO tetrapods for biological sensing (Chapter two-four), and further delineate the environmental implications of such nanomaterials using algae- the major constituent of the aquatic food chain-as a model system (Chapter five).
This dissertation is presented as follows.
Chapter one presents a general review of the characteristic properties, applications, forces dictating nanomaterials, and their biological and environmental implications of the most produced and studied soft and condensed nanomaterials. In addition, dendritic polymers and ZnO nanomaterials are thoroughly reviewed separately.
Chapter two investigates the physicochemical properties of poly(amidoamine)-tris(hydroxymethyl)amidomethane- dendrimer for its potential applications in water purification. The binding mechanisms and capacities of this dendrimer in hosting major environmental pollutants including cationic copper, anionic nitrate, and polyaromatic phenanthrene are discussed.
Chapter three exploits a promising use of dendrimers for removal of potentially harmful discharged nanoparticles (NPs). Specifically, fullerenols are used as a model nanomaterial, and their interactions with two different generations of dendrimers are studied using spectrophotometry and thermodynamics methods.
Chapter four elucidates two novel optical schemes for sensing environmental pollutants and biological compounds using dendrimer-gold nanowire complex and gold-coated ZnO tetrapods, respectively. The surface plasmon resonance of gold nanowires and NPs are utilized for enhancing the detection limits of Cu(II) down to nanomolar level and protein/lipids down to picomolar level.
Chapter five justifies the growing concern of the environmental implications of nanomaterials in light of the increasing environmental and biological applications of nanomaterials based on the previous chapters, using ZnO NPs and single-celled green algae, Chlorella sp. as a model system.
Chapter six summarized the key findings in this dissertation and presents future work stimulated by this Doctor of Philosophy (PhD) research.
In summary, the key scientific contributions of this dissertation are: 1). we have performed the first study on the versatility of a trifunctional dendrimer for hosting cationic, anionic, and polyaromatic chemical contaminants; 2). we have demonstrated for the first time the concept that a soft, biocompatible nanoparticle--a dendrimer, can be used for hosting discharged, harmful nanoparticles for environmental remediation; and 3). we have shown for the first time the impact of nanoparticles on aquatic organisms is bidirectional.

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