Doctoral Dissertations

Date of Award

5-2019

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Chemistry

Major Professor

Bin Zhao

Committee Members

Brian Long, Sheng Dai, Tongye Shen

Abstract

Surface-functionalized nanoparticles (SF-NPs) have great potential to be used in many fields including biosensors, medicines, catalysis, environmental remediation and energy storage. This dissertation work demonstrate the development of solutions confronting specific problems in the application of nanoparticles with surface functionalization strategy. Chapter 1 presents an introduction.The electrochemical performance of silicon anode in lithium-ion battery is closely related to the surface properties of silicon nanoparticles (SiNPs). In Chapter 2, an epoxy group is attached onto the surface of SiNPs through the formation of siloxane bond by surface silanization. Electrode based on epoxy-functionalized SiNPs shows a much improved cell performance due to the improved binding system by the chemical reaction between epoxy group and poly(acrylic acid) binder and the reduced parasitic reactions with electrolyte. In Chapter 3, a series of specially designed functional groups featuring ethylene oxide of different chain length terminated with an epoxy group are covalently attached to SiNPs by surface hydrosilylation. When employed as active materials for Si-graphite electrode, the surface-functionalized SiNPs improve cell performance with enhanced Li⁺ transport, stronger binding system and improved anode surface stability. A feasible way to make processable high refractive index (RI) optical materials is to introduce high RI inorganic nanofillers into the processable polymer matrix. A strong interaction between the two components is desired to prevent aggregation of nanoparticles in polymer. In Chapter 4, sulfur-containing polymer brush-grafted titanium dioxide (TiO₂) nanoparticles (hairy TiO₂ NPs) are made by surface-initiated atom transfer radical polymerization (SI-ATRP) .The incorporation of sulfur atom, which has high molar refraction, into side chain of vinyl monomers increases the intrinsic RI of the grafted polymer chains. The hairy TiO₂ NPs, featuring tunable ratio between grafted polymers and inorganic core, good dispersion and processability, have great potential to be used alone or to be used as building block in processable high RI nanocomposites. Chapter 5 presents surface functionalization of SiNPs by surface-initiated "living"/controlled radical polymerization (SI-LRP). Polymer-grafted SiNPs show good stability in common solvents and are expected to be applied in many practical fields including sustainable energy storage, semiconductors and optical industry. A conclusion and future perspective are given in Chapter 6.

Comments

Portions of this document were previously published in journal: Jiang, S.; Hu, B.; Sahore, R.; Zhang, L.; Liu, H.; Zhang, L.; Lu, W.; Zhao, B.; Zhang, Z., Surface-Functionalized Silicon Nanoparticles as Anode Material for Lithium-Ion Battery. ACS applied materials & interfaces 2018, 10 (51), 44924-44931.

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