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Temporal Control of Gelation and Polymerization Fronts Driven by an Autocatalytic Enzyme Reaction
Author(s) -
Jee Elizabeth,
Bánsági Tamás,
Taylor Annette F.,
Pojman John A.
Publication year - 2016
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201510604
Subject(s) - autocatalysis , polymerization , chemistry , induction period , hydrolysis , catalysis , polyethylene glycol , polymer chemistry , degradation (telecommunications) , base (topology) , reaction rate , chemical engineering , organic chemistry , polymer , telecommunications , mathematical analysis , mathematics , computer science , engineering
Chemical systems that remain kinetically dormant until activated have numerous applications in materials science. Herein we present a method for the control of gelation that exploits an inbuilt switch: the increase in pH after an induction period in the urease‐catalyzed hydrolysis of urea was used to trigger the base‐catalyzed Michael addition of a water‐soluble trithiol to a polyethylene glycol diacrylate. The time to gelation (minutes to hours) was either preset through the initial concentrations or the reaction was initiated locally by a base, thus resulting in polymerization fronts that converted the mixture from a liquid into a gel (ca. 0.1 mm min −1 ). The rate of hydrolytic degradation of the hydrogel depended on the initial concentrations, thus resulting in a gel lifetime of hours to months. In this way, temporal programming of gelation was possible under mild conditions by using the output of an autocatalytic enzyme reaction to drive both the polymerization and subsequent degradation of a hydrogel.