Preethi Aranala Gurumoorthi

Stimuli-responsive gels based on synthetic polymers have been well explored for their ability to undergo significant and reversible volume changes in response to environmental triggers such as temperature, pH, and solvent composition. Due to their adjustable physicochemical properties and responsive behavior, these materials are referred as "smart gels" and are used in drug delivery, tissue engineering, sensors, and actuators. In contrast, the stimuli-responsive behavior of gels based on biopolymers such as polysaccharide-based "bio-gels" are under explored. Although polysaccharides are abundant, renewable, and biocompatible, their use has traditionally been limited to roles as thickeners or texturizers in food and pharmaceuticals. Recent studies highlight the potential of polysaccharide gels to exhibit reversible swelling and contraction which opens new opportunities for bio-based, sustainable smart materials.

One of the main challenges in using bio-gels is understanding how their structure changes during processes such as solvent exchange and supercritical drying, which are important to make light-weight, highly porous bio-aerogels. Unlike many synthetic gels that tend to collapse completely in non-solvents, biopolymer gels usually contract but maintain their structure, which is a behavior that classical polymer theories do not completely explain. For a better prediction of the interactions of solvents and non-solvents with biopolymers, thermodynamic and kinetic modeling are combined with experimental studies to show the mass transfer within the gels and mechanical behavior of the gels. Gaining a deeper understanding of these processes will help in designing bio-aerogels with specific properties and could also lead to new types of sensors and devices that could take advantage of the reversible volume changes that are found in polysaccharide networks.