  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.
