Belousov鈥揨habotinsky Hydrogels: Relationship between Hydrogel Structure and Mechanical Response

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• 作者：Ryan C. Kramb ; Philip R. Buskohl ; Matthew J. Dalton ; Richard A. Vaia
• 刊名：Chemistry of Materials
• 出版年：2015
• 出版时间：August 25, 2015
• 年：2015
• 卷：27
• 期：16
• 页码：5782-5790
• 全文大小：389K
• ISSN：1520-5002

文摘

The novel chemo-mechanical feedback within autonomic Belousov鈥揨habotinsky (BZ) hydrogels mimics the complex adaptivity found in natural systems and inspires soft device concepts for chemical computing, sensing, and actuation. A quantitative relationship between the dynamic response, strain, BZ reagents, and hydrogel constituents, however, is still evolving due to a limited material suite. Using a modular synthesis strategy for free-radical BZ-catalyst monomers, we compare the impact of cross-linker, catalyst, and total polymer concentration on the cyclic strain of PNIPAm- and PAAm-based BZ hydrogels. The oscillator strain of the hydrogel in the BZ solution relative to the difference between equilibrium swelling of the fully oxidized and reduced states highlights the trade-off between BZ reaction kinetics, hydrogel elasticity, and catalyst concentration. For a PNIPAm-based BZ gel, a maximum strain of 20% occurs at a total polymer and [Ru] concentration of 4.8 卤 0.5 渭g/mm³ and 1.5 mM due to a complementary balance of Ru content, extended BZ period (33 卤 8 min), and modest network cross-linking. The modular synthesis approach enables formulation studies to identify the BZ hydrogel architecture that provides maximum strain response and robustness, as well as elucidating the interrelationship between hydrogel structure, composition, and reaction conditions.