Date of Award

8-9-2014

Document Type

Open Access Dissertation

Department

Chemistry and Biochemistry

First Advisor

John J. Lavigne

Abstract

Boronate esters have evolved from being primarily used as sensors to being the integral linkage in complex materials such as macrocycles, covalent organic frameworks, and linear polymers. Poly(boronate)s, linear polymers that are linked via a boronate ester, have not been extensively researched. In 2005, the Lavigne group published the first manuscript on poly(dioxaborolane)s, i.e., six-membered, nonconjugated polyboronates. The behavior of the materials in solution was studied extensively, but little is known about the solid state properties of the material other than they form brittle films.

Poly(dioxaborolane)s are generated in high yield through a facile step-growth polymerization, but the reaction parameters, such as monomer choice, solvent choice, and the ratio of monomer to solvent, were never investigated. Herein, the optimization of experimental parameters will be discussed with respect to the role each factor plays and how optimizing these conditions increase the ductility of the film. Several different poly(boronate)s were also synthesized to show the robustness of the polymerization as well as attempting to control material properties. The viscoelastic properties of the polyboronates materials show that they possess toughness between polystyrene and PET.

It is well known that boronate esters are susceptible to hydrolysis, which is a point of concern for poly(boronate) materials. Therefore, we investigated the stability of three different types of materials: a homopolymer, random copolymer that contained monomers that are capable of pi-pi stacking, and a mesoporous polymer that contains a nonplanar tetraol. It was discovered the most ductile and stable film is the non-porous homopolymer.

Finally, to gain a better understanding of materials that have boronate esters incorporated into the main chain of the polymer, we synthesized diboronic acid and tetraol monomers that contain flexible alkyl groups. Focusing on simple substitution reactions, we were able to successfully synthesize several tetraols.

Rights

© 2014, Shakena Daniel

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