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-acrylatechemistry 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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