Emulsion derived MOF coated fire retardant microcapsules for enhanced thermal safety in polymer based solid state system

Thermal safety remains a critical challenge for polymer-based solid-state systems because polymer electrolytes and polymer matrices are vulnerable to thermal degradation and flammability under elevated-temperature conditions. In this study, emulsion-derived fire-retardant microcapsules were developed by encapsulating a volatile fire-suppressing agent within a stable polymeric shell. DMTP was employed as the fire-retardant core material, while PEGDA and ETPTA were polymerized through UV-induced crosslinking to form a mechanically stable acrylate shell. To further enhance microcapsule functionality, a metal-organic framework coating was introduced onto the capsule surface, forming a porous protective layer that could improve thermal resistance and regulate molecular transport. Three preparation routes, including microfluidic emulsification, mechanical emulsification, and tip-sonication-assisted emulsification, were compared to control capsule size and morphology. The resulting microcapsules exhibited route-dependent particle sizes ranging from approximately 43 μm to 1 μm, with distinct morphological characteristics. Preliminary thermal and electrochemical evaluations suggested that the hybrid microcapsules could be incorporated into polymer-based systems without severe structural disruption. These results indicate that MOF-coated DMTP-loaded microcapsules are a promising platform for improving the thermal safety of polymer-based solid-state applications.
Keywords: Fire-retardant microcapsules, DMTP, PEGDA/ETPTA, MOF coating, Emulsion polymerization, Thermal safety.