Degree
Doctor of Philosophy (PhD)
Department
Chemistry
Document Type
Dissertation
Abstract
The development of time-lapse polymerization systems represents a significant advancement in the field of adhesives and hydrogels, enabling precise temporal control over material properties. This research presents a novel thiol-acrylate thermoset adhesive system, utilizing the urea-urease clock reaction as an enzymatic trigger for controlled polymerization. The approach integrates pH-mediated Michael addition reactions with antagonistic enzymatic catalysis, facilitating a scalable and tunable adhesive platform. By leveraging watermelon seed powder (WMSP) as a natural source of urease, the system generates ammonia in situ, modulating pH to initiate cross-linking at predetermined intervals. This strategy eliminates the need for external catalysts, enabling controlled gelation and adhesion in a one-pot formulation. In addition to adhesive formulations, this study investigates the temporal modulation of poly (vinyl alcohol)-borate (PVA-borate) hydrogels using coupled esterase-urease reactions to induce reversible gelation. The dynamic pH control enables multiple gel-degelation cycles, demonstrating potential for transient material applications. Comprehensive rheological and spectroscopic analyses confirm the precise regulation of polymerization kinetics, with tunable parameters including urease concentration, urea loading, and initial pH. The adhesive formulations exhibit superior mechanical properties, with peak tensile strengths exceeding 7 MPa and robust adhesion across multiple substrates. This work pioneers the integration of enzymatic clock reactions into polymer science, expanding the functional versatility of thiol-acrylate chemistry. The findings provide a foundation for the next generation of time-controlled adhesives and hydrogels, with potential applications in coatings, controlled assembly, and smart material design.
Date
4-23-2025
Recommended Citation
Shaon, Fahima, "Time Lapse Adhesives and Hydrogels: A Novel Approach Utilizing Michael Addition Reaction Coupled with Clock Reaction" (2025). LSU Doctoral Dissertations. 6779.
https://repository.lsu.edu/gradschool_dissertations/6779
Committee Chair
Pojman, John A.
DOI
10.31390/gradschool_dissertations.6779