Date of Completion

1-8-2018

Embargo Period

1-8-2018

Keywords

Nanocoating, flow-induced orientation, coassembly, polyvinyl alcohol, montmorillonite, laponite, α-zirconium phosphate, and graphene oxide, barrier, flame retardancy

Major Advisor

Dr. Luyi Sun

Associate Advisor

Dr. Montgomery T. Shaw

Associate Advisor

Dr. Richard Parnas

Field of Study

Materials Science

Degree

Doctor of Philosophy

Open Access

Open Access

Abstract

In this dissertation, a novel approach to fabricate organic/inorganic nanocoatings via a large-scale one-step coassembly process has been developed. The fabricated nanocoatings contain a high concentration of nanosheets (up to 70 wt. %) that can be well aligned along the substrate surface. A series of nanocoatings based on polyvinyl alcohol (PVA) together with various nanosheets including montmorillonite (MMT), laponite (LP), α-zirconium phosphate (ZrP), and graphene oxide (GO) were successfully fabricated using this one-step coassembly process. Different from other methods, this approach offers a high-speed one-step coassembly, in which hundreds of nanosheets can be aligned along the flow direction to form a highly orientated structure with PVA sandwiched in between the layers. Due to their unique structure, the nanocoatings exhibited exceptional optical, mechanical, barrier, and flame retardant properties. The composition of the nanocoatings can be easily adjusted, leading to tunable properties.

Taking advantage of the unique structure of the nanocoatings, several applications were explored to demonstrate the versatility of the system. The superior gas barrier and flame retardant performance of the nanocoatings allow for uses as packaging and fire barrier materials, respectively. The nanocoatings of PVA/MMT can be applied to current polymer dielectric films to significantly enhance their dielectric performance. As well as, by utilizing the moisture-responsive nature of PVA, PVA/LP nanocoatings with writable patterns were designed and prepared, which may find applications in forgery prevention and encryption.

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