Self-Foaming, Oil-Absorbable, Flame Self-Extinguishing and Thermal Insulation POSS/PDMS Foams

Polydimethylsiloxane (PDMS) foams have attracted tremendous interest in both academia and industry due to their lightweight, excellent elasticity, and superior thermal stability. However, their flammability, poor mechanical durability, and cumbersome preparation process severely hinder their practical application. To overcome these limitations, a hydrogen-generated and self-foaming strategy is proposed to fabricate multifunctional PDMS foams at room temperature through incorporating phenyl trisilanol POSS (T₇-POSS-OH) into matrices of vinyl-terminated PDMS and polymethylhydrosiloxane (PMHS) in the presence of the Karstedt catalyst. Interestingly, the resulting PDMS foam exhibits ultralow thermal conductivity (<0.04 W m·K^-1), reversible mechanical compressibility, excellent stability in harsh conditions (including exposures to acid, alkali, salt, and high temperatures), efficient oil-water separation performance, and superior flame self-extinguishing properties. Notably, the resulting PDMS foam exhibits prominent heat-insulating performance even after direct exposure to a 1300 °C flame for 300 s. The exceptional thermal insulation is primarily attributed to the formation of a porous carbonaceous ceramic layer during combustion. This work not only presents an innovative strategy for simultaneously enhancing mechanical properties, flame-retardancy, and thermal insulating properties of the PDMS foams, but also provides a highly advanced multifunctional material with tremendous potential for applications in environmental remediation, fire-retardant engineering, and thermal insulation technologies.