The technical objective of this project was to develop a novel approach for fighting gasoline pool fires based on fire-retardant additive-releasing smart beads and particles. This limited-scope research work aimed to develop non-fluorinated, biodegradable, water-dispersible polymer beads incorporated with phosphorus-nitrogen fire-retardant additives. These beads and particles were expected to function as additives for fluorine-free firefighting foams to enhance the firefighting performance.

Technical Approach

A Class B firefighting formulation using fire-retardant additive-releasing smart beads dispersed in water was investigated. The smart beads were designed to release the fire-retardant chemical immediately when the bead is exposed to fire. Smart polymeric beads were prepared incorporating a phosphorus-nitrogen fire-retardant chemical. In addition to smart beads, Pickering foams, hydrogel particles, and polymers as stabilizers were conducted, and their effect on the firefighting performance of a foam formulation was studied.


Three categories of foam additives were incorporated into a hydrocarbon surfactant-based 3% concentrate foam formulation. Hydrogel and hydrophobic silica nanoparticles as foam stabilizers significantly improved residence time on fuel surfaces in small-scale experiments. However, similar effects were not observed in large-scale applications. Integration of particle additives into foam systems did not significantly increase stability for this surfactant system under fire. The particle additives possibly act as heat absorption sources and rapidly destabilize the foams under heat. This effect is counter-productive for pool firefighting applications. Therefore, the local heating effect of the dispersed particles needs to be taken into account when formulating firefighting foams with particle additives.


The foam concentrates developed in this project can be helpful in industrial fields where emulsions play an integral role. Enhanced oil recovery and pharmaceutical delivery mechanisms may benefit from the results of this study. Further experimentation may include an in-depth investigation of the impact of colloidal additives on foam degradation mechanisms and the use of anisotropic Janus particles. Extinguishing and suppressing Class B fires via particle-added foam concentrates remains a significant technical hurdle.