Title page for ETD etd-09182012-150731


Type of Document Dissertation
Author Bounds, Christopher O.
URN etd-09182012-150731
Title Fabrication, Analysis, Application, and Characterization of Core-Containing Microparticles and Hydrophilic Microfluidic Devices Produced Via the Primary- and In Situ Tertiary-Amine Catalyzed Michael Addition of Multifunctional Thiols to Multifunctional Acrylates
Degree Doctor of Philosophy (Ph.D.)
Department Chemistry
Advisory Committee
Advisor Name Title
Pojman, John A. Committee Chair
Hayes, Daniel Committee Member
Spivak, David Committee Member
Zhang, Donghui Committee Member
Bao, Huiming Dean's Representative
Keywords
  • Thiol-Acrylate
  • Thiol-Ene
  • Microencapsulation
  • Microfluidic devices
  • Lewis Acid Catalyst
  • In Situ Bound Catalyst
Date of Defense 2012-08-08
Availability unrestricted
Abstract
The objective of this research was to investigate amine-catalyzed thiol-acrylate

chemistry for various novel applications that could fully utilize the untapped potential of

this useful and robust chemistry. The use of this chemistry in each application solved a

problem, improved on a disadvantage of current technologies, and decreased the level

of complexity in association with required time, cost, and/or preparation conditions. The

first novel application conceived, applied, and analyzed was in the field of

microencapsulation. A novel approach for the preparation of microparticles via a

dispersion polymerization using the primary amine-catalyzed addition of a trithiol to a

triacrylate was realized and investigated. Various core materials were

microencapsulated via this technique and introduced into appropriate systems to

improve the desired characteristics of the given system. In a specific case,

microparticles containing a borontrichloride-amine complex were observed to prevent

the interaction between the Lewis acid initiator and fumed silica, hence improving the

rheological properties of an epoxy system containing the initiator while maintaining the

strength of the resulting polymer. Another application involved a novel approach to

prepare stable hydrophilic microfluidic devices. Hydrophilic thiol-acrylate materials were

fabricated with native stable water contact angles of ~60° via a two-pot soft lithography

technique at room temperature, very rapidly, and with little equipment. The material

hydrophilicity was modified from 10-85° via bulk- or post-modification techniques. These

materials were prepared via the Michael addition of a secondary amine to a

multifunctional acrylate, producing a nonvolatile tertiary amine utilized in the catalysis of  

the Michael addition of a multifunctional thiol to the multifunctional acrylate. Because the

final chip was self-adhered via a chemical process utilizing the same chemistry, and it

was naturally hydrophilic, there was no need for expensive equipment or methods to

“activate” the surface. Also, due to the pre-synthesized monomer/catalyst molecule

serving as the in situ catalyst, there was no need for post-processing removal of the

catalyst as it was incorporated into the polymer network. Both novel applications

facilitated great improvements by exploiting the major advantages of thiol-acrylate

chemistry. The fabrication, analysis, application, and characterization of these novel

amine-catalyzed thiol-acrylate microparticles and microfluidic devices are described.

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