Published in

Elsevier, Sensors and Actuators B: Chemical, (206), p. 456-462, 2015

DOI: 10.1016/j.snb.2014.09.089

Links

Tools

Export citation

Search in Google Scholar

Modulating the movement of hydrogel actuator based on catechol–iron ion coordination chemistry

Journal article published in 2015 by Bruce P. Lee ORCID, Meng-Hsien Lin, Ameya Narkar, Shari Konst, Randall Wilharm
This paper was not found in any repository, but could be made available legally by the author.
This paper was not found in any repository, but could be made available legally by the author.

Full text: Unavailable

Green circle
Preprint: archiving allowed
Orange circle
Postprint: archiving restricted
Red circle
Published version: archiving forbidden
Data provided by SHERPA/RoMEO

Abstract

Hydrogel actuators were prepared by combining ionoprinting technique with reversible metal ion coordination chemistry found in mussel adhesive proteins. Hydrogels were formulated with dopamine methacrylamide (DMA), which contains a catechol side chain that forms strong complexes with ferric (Fe3+) ions. Catechol–Fe3+ ion complexation increased local crosslinking density, which induced hydrogel bending at the site of ionoprinting. The effect of multiple factors on the dynamic response of hydrogel actuation was tracked by following the bending curvature at the ionoprinting site. In general, the extent and rate of hydrogel actuation increased with increasing pH, deposited Fe3+ ion content, and DMA content but was inversely proportional to hydrogel thickness. The ability to modulate hydrogel actuation using multiple parameters is potentially useful in controlling the actuator movements. Additionally, Fe3+ ion-containing bulk hydrogels demonstrated significant reduction in molecular weight between crosslinks as well as elevated storage and loss modulus values based on oscillatory rheometry when compared to those of Fe3+-free control. These differences in physical and viscoelastic properties contributed to the actuation of ionoprinted samples. Specifically, conditions that promoted a large crosslinking differential between the ionoprinted region and the bulk hydrogel (i.e., outside of the ionoprinted region) contributed to increased rate and extent of hydrogel folding. Faster actuation at elevated pH levels was attributed to the formation of complexes with higher catechol:Fe3+ ion stoichiometric ratios. Hydrogel actuation and deswelling were also observed at pH of 3.5 although to a lesser degree, potentially due to a stronger affinity between network-bound catechol and Fe3+ ions as compared to complexes formed in a dilute solution.