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[Display omitted] • The constructed similar structure reduces binding energy between MXene and PU. • 120 °C is achieved under two suns through synergistic photothermal effect. • MXene-TT/PU shows a large reduction of 47.06% in peak heat release rate. • Flame retardancy mechanism is revealed through molecular dynamic simulation. MXene, renowned for its exceptional metallic conductivity, thermal conductivity, and tunable surface chemistry, has shown great potential for various applications in energy storage, catalysis, electromagnetic shielding and photothermal conversion. However, the inherent inorganic nature of MXene poses a significant challenge in excavating its potential when incorporated into organic polymer matrix. Herein, we develop an interface engineering strategy to functionalize the surface chemistry of MXene via in-situ polymerization of tannic acid and toluene diisocyanate (TA and TDI, abbreviated as TT), protecting the MXene from oxidation while enhancing the interface compatibility between MXene and polyurethane (PU). MXene-TT/PU with high machinability, processibility and thermal stability is achieved through the urethane groups interactions from MXene-TT and PU, which shows a large reduction of 47.06% in peak heat release rate and 24.53% in peak total heat release, respectively. The mechanism of greatly improved flame retardancy is revealed by Molecular dynamic simulations. Moreover, MXene-TT/PU also exhibits rapid photothermal de-icing under simulated solar irradiation, with the surface ice begin to thaw in ∼30 s. This design concept, which is based on similar molecular structures, provides an effective approach to address the interfacial and stability issues associated with MXene, thereby enhancing its flame retardancy, mechanical properties, and photothermal de-icing capabilities. [ABSTRACT FROM AUTHOR]

Taking into consideration the frigid and thunderstorms, the flame retardancy and de-icing performance are simultaneously desiderated for some open-air key equipment, such as air fuselage and wind turbine blades. Here, inspired by the anti-reflection phenomenon of moth eyes and cicada wings, a multi-functionalized and biomimetic MXene@SnO 2 hierarchical nanostructure is prepared to effectively impart flame retardancy and solar de-icing performance to thermoplastic polyurethane (TPU) resin used widely as the finishing coat of protective materials of open-air equipment. Based on the catalytic effect and barrier function, the addition of hierarchical MXene@SnO 2 nanostructures also effectively decreases the release of heat and toxic smoke from PU resin, as confirmed by reductions of 50.5% and 33.1% in the peak heat release rate and smoke production rate, respectively. Due to the appropriate refractive index, the light reflection phenomenon is effectively suppressed, thus promoting solar absorption (∼90% at 0.4 mm film) and photo-thermal conversion (∼74.2 °C with simulated solar illumination of 1.0 kW/m2) in TPU-MXene@SnO 2 nanocomposites. Within the environment of −20 °C, the surface temperature of TPU-MXene@SnO 2 nanocomposites is still up to 32.7 °C and the surface ice pellet begins to melt at ∼40s, much earlier than 600s of pure TPU resin. In addition, the practical application of functionalized TPU nanocomposites is further improved by the higher mechanical properties, attributed to the strong interfacial interaction. Inspired by moth eyes and cicada wings, flame retardancy and solar de-icing performance are first integrated into polymer materials, thus effectively promoting their application in some extreme environments. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • A flame-retardant and photo-thermal microstructure is synthesized. • Thermochromic materials and bio-based flame retardants are used as core and shell. • Heat release and smoke production are effectively suppressed. • The melting and slide of ice block is accelerated by solar-thermal conversion. Due to the extreme dynamic weather, important industrial facilities and infrastructure providing vital support for people's lives usually face the hazards of fire and icing, especially in the weather of thunderstorm and ice. Therefore, to further establish a safe community, we develop a dual-functional polyurea (PUA) coating used as protective materials by introducing flame retardancy and solar de-icing performance. Based on the microencapsulation and electrostatic self-assembly technologies, flame-retardant and thermochromic microcapsules (TCM) are firstly prepared and then added into PUA resin, by using melamine resin and bio-based phytic acid/chitosan (PA/CS) hybrids as double-shell materials. The high phosphorus content of PA and the carbon-forming effect of CS together play a synergistic flame retardant effect, not only improving the thermal stability of microcapsules but also enhancing the flame retardant property of PUA coating. In the cone calorimetry test, the ignition time of TCM@PA/CS@PUA-3 is longer, and the pHRR is reduced by 19.93 %, which shows the improvement of flame retardant performance. Due to the thermochromic mechanism, TCM@PA/CS@PUA composite coatings are able to adjust the photo-thermal conversion ability according to different environment temperature, achieving less temperature in hot environment and higher temperature in cold environment. The excellent photo-thermal conversion ability also promotes the ice melting and slide in 525 s. This polyurea composite coating with both flame retardant and de-icing properties shows great potential for maintaining the normal operation and safety of outdoor industrials and infrastructure in extremely dynamic weather conditions. [ABSTRACT FROM AUTHOR]

[Display omitted] • This work focuses on the sustainability and safety of radiative cooling materials. • Bio-based chitosan and phytic acid are used to prepare radiative cooling film. • The radiative cooling effect and fireproof performance are presented simultaneously. Even though significant advantages in the energy-free regulation of temperature are presented, the practical applications of radiative cooling materials in buildings and human surfaces still involve many safety issues, especially for fire hazards of polymer-based materials. Meanwhile, renewable and environmentally friendly materials are urgently needed to develop suitable radiative cooling materials with no adverse environmental impact. Herein, a chitosan-derived composite aerogel film with high solar reflection provided by the addition of melamine-phytic acid (MA/PA) hybrids is designed and prepared, presenting radiative cooling and fireproof performances. The instinct deep-yellow color of chitosan (CS) is successfully shielded by high-reflective MA/PA hybrids, while IR emissivity of up to 90.4 % and solar reflectivity of ∼ 89.3 % are achieved. In outdoor environments, this composite aerogel shows sub-ambient temperature drops of ∼ 4.3 °C and ∼ 3.1 °C in cloudless and cloudy weather, presenting a robust cooling effect. In addition, CS-MA/PA composite aerogel film with 3 mm thickness can isolate the fire of ∼ 500 °C, showing superior fire safety attributed to the synergistic flame retardant effects among chitosan, phytic acid, and melamine, which suppress the initial growth of fire and promote the rapid formation of protective char layer. This work provides a bio-based, fire-safe, and radiative cooling material to decrease the energy consumption of temperature regulation with a more environmentally friendly and safer approach, further promoting the practical application of radiative cooling materials. [ABSTRACT FROM AUTHOR]