Pioneering hydrogel cooling technologies: A comprehensive approach to theoretical modeling and one-step fabrication strategy

Abstract

To address the pressing challenges of economic loss and environmental concerns in the cold-chain sector due to temperature-related degradation and microbial contamination, we introduce reusable hydrogel cooling technology. “Jelly Ice Cubes” (JICs), bio-based hydrogel coolants offering a sustainable and efficient alternative to traditional cooling agents. This study reveals for the first time that the essence of designing any hydrogel coolant hinges on establishing an ideal structure, which maintains freezable water within a heterogeneously distributed closed-cell matrix crucial for stable superior cooling performance. A mathematical model was developed to define the optimal parameters for the structure of a closed-cell matrix, maximizing its water-retaining and heat-absorbing capabilities. Specifically, we explicitly explained how the size of enclosed chambers varies with the changes in biopolymer molecular size and concentration, as well as freezable water content in the hydrogel. Moreover, scalable one-step chemical crosslinking processes were developed based on the optimized structure provided by the models, enabling controllable gelatin crosslinking in hydrogels to achieve the desired structural features. The JICs demonstrate significant promise for decarbonization efforts in many fields, especially by optimizing packaging efficiency in cold-chain logistics. This research not only bridges a significant gap by applying a theory-driven approach to the development of sustainable hydrogel-based cooling technologies, but also sets a new standard for future innovations in the field.