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DOE OSTI · 1839330

Patterned crystal growth and heat wave generation in hydrogels

Schroeder, Thomas B. H. (ORCID:0000000327951730)·Aizenberg, Joanna (ORCID:0000000223438705)
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Abstract

Abstract The crystallization of metastable liquid phase change materials releases stored energy as latent heat upon nucleation and may therefore provide a triggerable means of activating downstream processes that respond to changes in temperature. In this work, we describe a strategy for controlling the fast, exothermic crystallization of sodium acetate from a metastable aqueous solution into trihydrate crystals within a polyacrylamide hydrogel whose polymerization state has been patterned using photomasks. A comprehensive experimental study of crystal shapes, crystal growth front velocities and evolving thermal profiles showed that rapid growth of long needle-like crystals through unpolymerized solutions produced peak temperatures of up to 45˚C, while slower-crystallizing polymerized solutions produced polycrystalline composites and peaked at 30˚C due to lower rates of heat release relative to dissipation in these regions. This temperature difference in the propagating heat waves, which we describe using a proposed analytical model, enables the use of this strategy to selectively activate thermoresponsive processes in predefined areas.

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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRYgelshydrogelsinformation storageorganic molecules in materials science

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Schroeder, Thomas B. H. (ORCID:0000000327951730), Aizenberg, Joanna (ORCID:0000000223438705). 2022-01-11. Patterned crystal growth and heat wave generation in hydrogels. https://doi.org/10.1038/s41467-021-27505-z

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