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Owing to their preeminent properties, including mechanical flexibility, thermal insulation, and low cost, silicone foams are widely used in industrial fields. However, flame‐induced structural failure greatly restricts their practical applications. It is challenging for flexible silicone foams to realize reliable thermal protection in thermo–mechanical–oxidative environments. Inspired by traditional pottery, a multiscale‐filler synergistic ceramifiable strategy for creating silicone foam nanocomposites with flexibility and long‐term fireproofing is proposed herein. The foam materials not only maintain mechanical flexibility and elasticity (≈2% residual strain after 1000 cycles) at a temperature range of −60–210 °C but also exhibit exceptional long‐term (>30 min) thermal insulation upon exposure to ≈1300 °C oxidative environments because of their ability to form a gradient robust porous ceramic structure. Moreover, the foam material can provide stable thermal protection for electric cables and lithium‐ion battery packs, making it one of the most reliable thermal insulation materials so far. This work broadens the applications of silicone foams in emerging fields where mechanical buffering and fireproofing are required. [ABSTRACT FROM AUTHOR]

Polydimethylsiloxanes (PDMS) foam as one of next-generation polymer foam materials shows poor surface adhesion and limited functionality, which greatly restricts its potential applications. Fabrication of advanced PDMS foam materials with multiple functionalities remains a critical challenge. In this study, unprecedented self-adhesive PDMS foam materials are reported with worm-like rough structure and reactive groups for fabricating multifunctional PDMS foam nanocomposites decorated with MXene/cellulose nanofiber (MXene/CNF) interconnected network by a facile silicone foaming and dip-coating strategy followed by silane surface modification. Interestingly, such self-adhesive PDMS foam produces strong interfacial adhesion with the hybrid MXene/CNF nano-coatings. Consequently, the optimized PDMS foam nanocomposites have excellent surface super-hydrophobicity (water contact angle of ≈159o), tunable electrical conductivity (from 10-8 to 10 S m-1), stable compressive cyclic reliability in both wide-temperature range (from -20 to 200 °C) and complex environments (acid, sodium, and alkali conditions), outstanding flame resistance (LOI value of >27% and low smoke production rate), good thermal insulating performance and reliable strain sensing in various stress modes and complex environmental conditions. It provides a new route for the rational design and development of advanced PDMS foam nanocomposites with versatile multifunctionalities for various promising applications such as intelligent healthcare monitoring and fire-safe thermal insulation. [ABSTRACT FROM AUTHOR]

• Introducing phenyl groups onto Si–O–Si chains can tailor the foaming and cross-linking match. • The lowest density of the optimized PhSiRF material is as light as ∼100 mg/cm3. • The pore structure and morphology in the PhSiRF materials can be easily achieved. • The PhSiRF presents good wide-temperature flexibility and exceptional thermal insulation. Silicone foam materials with unique inorganic/organic molecular networks and porous structures are widely used in many emerging fields from aerospace to new energy fields. However, current silicone foam materials still show some limitations, such as the relatively high-density values of >200 mg cm−3, complex fabricating process and difficulty in tailoring pore structure. Herein, we report a large-scale and facile fabricating strategy to prepare phenyl-containing silicone foam materials (PhSiRF) with ultra-lightweight feature, tunable pore structure, and excellent wide-temperature mechanical flexibility. Interestingly, the presence of phenyl groups onto the Si–O–Si backbone tailors the chemical foaming rate probably due to the steric hindrance effect, thus producing tunable pore size distributions in the range of 180–500 μm. Typically, the PhSiRF with 50 % phenyl groups not only shows a very low density of ∼100 mg cm−3, superior to previous silicone foams and composites, but also exhibits wide-temperature flexibility (stable compressive strain of 80 % from −90 to 210 °C) and excellent thermal insulation performance, which outperforms those of conventional polymer foams including polyurethane, polyethylene and melamine foams. Based on the structure observation and theory analysis, the influence of different pore morphological structures on the thermal insulation performance is discussed and demonstrated. Clearly, this work provides a new yet simple method for developing high-performance silicone rubber foam materials for promising thermal insulation applications. [ABSTRACT FROM AUTHOR]