Smart fire safety ionogels with widely tunable mechanical properties

• Multifunctional flame-retardant ionogels (MFIGs) were fabricated. • Phase structure of MFIGs was regulated from “sea-island” to co-continuous phase. • Mechanical properties of MFIGs could be widely tuned by adjusting phase structure. • MFIGs showed outstanding flame retardancy and multiple fire-warning performance. It is significant to fabricate mechanically tunable and highly fire-safety ionogels for meeting the requirements in different application fields. In this work, multifunctional flame-retardant ionogels (MFIGs) with widely tunable mechanical properties were fabricated via in situ UV-initiated polymerization of acrylamide and acrylic acid dispersed in flame-retardant phosphorous-containing ionic liquid. The mechanical properties of MFIGs could be regulated by adjusting the phase structure via changing the content of PIL and monomers. MFIGs were robust and rigid (tensile strength of 9.9 MPa and modulus of 2.1 MPa) when they showed “sea-island” structure, and were flexible and stretchable (modulus of 51.1 kPa and elongation at break of 587%) when a co-continuous phase formed. MFIGs exhibited outstanding flame retardancy with a limiting oxygen index of 54.5%. Meanwhile, MFIGs showed good electrical resistance response and thermoelectric conversion properties, which had multiple fire-warning performance to further enhance fire safety. Our work provides new insights for the fabrication of multifunctional and smart fire protection ionogels.