Flammability feature of combustible polymer foam materials often causes massive casualties and property loss, and it is therefore urgent to develop a green and high-efficiency strategy that can reduce or avoid the fire blaze disasters. Here, an extremely simple water-based coating approach is proposed to prepare mechanically flexible, super-hydrophobic and flame-retardant polyurethane (PU) foam nanocomposites with high-efficiency fire warning response. The hybrid ammonium polyphosphate (APP)/graphene oxide (GO) is decorated onto the PU foam surface via electrostatic interactions followed by surface silane functionalization. Interestingly, the silane and APP molecules present selective distributions on the GO and thus form micro-/nano- rough surface with low water affinity to achieve super-hydrophobicity (e.g. water contact angle of ~158.4°). Meanwhile, such hybrid APP/GO/silane coatings produce synergistic flame resistance for the PU foam materials, which is attributed to the formation of compact and uniform P-Si elements co-covered rGO layer on the foam surface. Further, the hybrid coatings can provide high-efficiency fire warning response under complicated conditions, e.g. flame detection response time of only ~2.0 s and excellent fire early warning time in pre-combustion (e.g. 11.2 s at 300 °C). Therefore, this work provides new perspectives to design and develop multi-functional coatings for fire safety and prevention applications.

Water-based hybrid coatings toward mechanically flexible, super-hydrophobic and flame-retardant polyurethane foam nanocomposites with high-efficiency and reliable fire alarm response

Temperature-responsive resistance sensitivity controlled by L-ascorbic acid and silane co-functionalization in flame-retardant GO network for efficient fire early-warning response

The most pressing challenges for light-driven hydrogel actuators include reliance on UV light, slow response, poor mechanical properties, and limited functionalities. Now, a supramolecular design strategy is used to address these issues. Key is the use of a benzylimine-functionalized anthracene group, which red-shifts the absorption into the visible region and also stabilizes the supramolecular network through π-π interactions. Acid-ether hydrogen bonds are incorporated for energy dissipation under mechanical deformation and maintaining hydrophilicity of the network. This double-crosslinked supramolecular hydrogel developed via a simple synthesis exhibits a unique combination of high strength, rapid self-healing, and fast visible-light-driven shape morphing both in the wet and dry state. As all of the interactions are dynamic, the design enables the structures to be recycled and reprogrammed into different 3D objects.

Strong, Self-Healable, and Recyclable Visible-Light-Responsive Hydrogel Actuators.

Facile and green fabrication of flame-retardant Ti3C2Tx MXene networks for ultrafast, reusable and weather-resistant fire warning

Facile and green synthesis of mechanically flexible and flame-retardant clay/graphene oxide nanoribbon interconnected networks for fire safety and prevention

Bioinspired Color Changing Molecular Sensor toward Early Fire Detection Based on Transformation of Phthalonitrile to Phthalocyanine

The practical problems of insufficient mechanical strength, poor processability, tedious synthesis and flammability facing shape memory polymers have limited their further usage in industrial fields, especially in construction and aerospace. A novel and very simple method of ternary polymerization is presented here to prepare multi-functional copolyesters from general poly(ethylene terephthalate) (PET) through the new well-designed third monomer that features pendent phenylacetylene–phenylimide units. The π–π stacking between phenylacetylene groups as a reversible net-point not only endows the copolyesters with good shape memory and self-healability, but also reinforces the interchain interaction, leading to high tensile strength (79.6–89.6 MPa). Interestingly enough, the phenylacetylene can synergistically crosslink with the unsaturated CN group generated from the phenylimide during burning, resulting in excellent flame retardancy. Thermoplastic smart copolyesters can be designed into fire alarms and can also be used for 3D printing. The printed geometries exhibit good shape memory behaviors, which could be deformed into a small size to save space during transportation/storage and allow manufacturing freedom for space applications.

Wan-Shou Wu

Papers

Bioinspired Color Changing Molecular Sensor toward Early Fire Detection Based on Transformation of Phthalonitrile to Phthalocyanine

3D printable robust shape memory PET copolyesters with fire safety via π-stacking and synergistic crosslinking

Semi-aromatic copolyesters with high strength and fire safety via hydrogen bonds and π-π stacking

Fire hazards management for polymeric materials via synergy effects of pyrolysates-fixation and aromatized-charring.

How Hydrogen Bond Interactions Affect the Flame Retardancy and Anti‐Dripping Performances of PET