Water-enhancing gels exhibiting heat-activated formation of silica aerogels for protection of critical infrastructure during catastrophic wildfire

TL;DR

This paper introduces a novel heat-activated hydrogel that transforms into silica aerogel, providing enhanced fire protection for infrastructure during wildfires by maintaining thermal insulation even after desiccation.

Contribution

Developed a sustainable, biomimetic hydrogel that transitions into silica aerogel upon heating, offering improved fire resistance over existing water-enhancing gels.

Findings

Hydrogel exhibits ideal viscoelastic properties and strong adherence.

Heat activation creates a porous silica aerogel coating.

Enhanced protection against ignition demonstrated.

Abstract

A promising strategy to address the pressing challenges with wildfire, particularly in the wildland-urban interface (WUI), involves developing new approaches for preventing and controlling wildfire within wildlands. Among sprayable fire-retardant materials, water-enhancing gels have emerged as exceptionally effective for protecting civil infrastructure. They possess favorable wetting and viscoelastic properties that reduce the likelihood of ignition, maintaining strong adherence to a wide array of surfaces after application. Although current water-enhancing hydrogels effectively maintain surface wetness by creating a barricade, they rapidly desiccate and lose efficacy under high heat and wind typical of wildfire conditions. To address this limitation, we developed unique biomimetic hydrogel materials from sustainable cellulosic polymers crosslinked by colloidal silica particles that exhibit ideal viscoelastic properties and facile manufacturing. Under heat activation, the hydrogel transitions into a highly porous and thermally insulative silica aerogel coating in situ, providing a robust protective layer against ignition of substrates, even when the hydrogel fire suppressant becomes completely desiccated. By confirming the mechanical properties, substrate adherence, and enhanced substrate protection against fire, these heat-activatable biomimetic hydrogels emerge as promising candidates for next-generation water-enhancing fire suppressants. These advancements have the potential to dramatically improve our ability to protect homes and critical infrastructure during wildfire.