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Lightweight polymeric materials are highly attractive platforms for many potential industrial applications in aerospace, soft robots, and biological engineering fields. For these real-world applications, it is vital for them to exhibit a desirable combination of great toughness, large ductility, and high strength together with desired healability and biocompatibility. However, existing material design strategies usually fail to achieve such a performance portfolio owing to their different and even mutually exclusive governing mechanisms. To overcome these hurdles, herein, for the first time a dynamic hydrogen-bonded nanoconfinement concept is proposed, and the design of highly stretchable and supratough biocompatible poly(vinyl alcohol) (PVA) with well-dispersed dynamic nanoconfinement phases induced by hydrogen-bond (H-bond) crosslinking is demonstrated. Because of H-bond crosslinking and dynamic nanoconfinement, the as-prepared PVA nanocomposite film exhibits a world-record toughness of 425 ± 31 MJ m -3 in combination with a tensile strength of 98 MPa and a large break strain of 550%, representing the best of its kind and even outperforming most natural and artificial materials. In addition, the final polymer exhibits a good self-healing ability and biocompatibility. This work affords new opportunities for creating mechanically robust, healable, and biocompatible polymeric materials, which hold great promise for applications, such as soft robots and artificial ligaments., (© 2021 Wiley-VCH GmbH.)

Biodegradable polymeric materials with high strength and outstanding toughness are necessary for real‐world applications in the fields of electronics, electrics, and packaging. Unfortunately, such performance portfolios in polymers remain challenging to achieve due to their different governing mechanisms. Inspired by the hydrogen‐bond (H‐bond) cross‐linking structure of spider silk, herein, strong and tough poly(vinyl alcohol) (PVA) composites with β‐cyclodextrin as a cross‐linker are developed. Benefiting from the H‐bond cross‐linking effect, the addition of 1.0 wt% of β‐cyclodextrin enables PVA to achieve a high tensile strength of 136.5 MPa, and a high elastic modulus of 3.0 GPa, in combination with a good toughness of 82.1 MJ m−3. In addition, the presence of β‐cyclodextrin improves the biodegradability of PVA composite by decreasing its crystalline size. Furthermore, PVA/β‐cyclodextrin composite combined with MXene has great potential as a sensor material for humidity and strain detection. This proof‐of‐concept opens numerous opportunities to create strong, tough, and biodegradable polymers for packing and sensing applications. [ABSTRACT FROM AUTHOR]

Recently, soaring developments in microelectronics raise an urgent demand for thermal management materials to tackle their "overheating" concerns. Polymer nanocomposites are promising candidates but often suffer from their inability of mass production, high‐cost, poor mechanical robustness, and even flammability. Hence, it is desirable to scalably fabricate low‐cost, robust polymeric nanocomposites that are highly thermally conductive and fire‐retardant to ensure safe and efficient thermal management. Herein, the scalable production of nacre‐like anisotropic nanocomposite films using the layer‐by‐layer assembly of phenylphosphonic acid@graphene nanoplatelets (PPA@GNPs)‐poly(vinyl alcohol) (PVA) layer and GNPs layers, is demonstrated. The PPA serves as interfacial modifiers and fire retardants for flammable PVA (film‐forming agent) and GNPs (inexpensive conductive nanofillers) via hydrogen‐bonding and π–π stacking. The resultant nanocomposite exhibits a high flexibility, high tensile strength of 259 MPa, and an ultrahigh in‐plane thermal conductivity of 82.4 W m‐1 K‐1, making it effectively cool smartphone and high‐power light emitting diode modules, outperforming commercial tinfoil counterparts. Moreover, the as‐designed nanocomposites are intrinsically fire‐retardant and can shield electromagnetic interference. This work offers a general strategy for mass production of thermally conductive nanocomposites holding great promise as thermal management materials in electronic, military, and aerospace fields. [ABSTRACT FROM AUTHOR]

[Display omitted] • A multifunctional small molecule (HCPA) has been prepared. • The presence of HCPA endowed PVA with a nanostructure within the continuous matrix. • 5 wt% of HCPA endows PVA with a self-extinguishing behavior. • 5 wt% of HCPA increases tensile strength of PVA by 47% and toughness by 370%. • The PVA/HCPA composites exhibit a water-trigged healing efficiency over 90%. The combination of high fire retardancy, high strength, and great toughness as well as good healability is essential for successful real-world applications of polymeric materials in the fields of packaging, electronics & electrics, and optical devices. To date, there have been few successes in achieving such performance portfolios in polymers due to their different and even mutually exclusive governing mechanisms. Inspired by the nanoconfinement effect that governs the unique mechanical properties of spider silk, we, herein, rationally design a multifunctional small molecule, HCPA, that can serve as a fire retardant and hydrogen-bond crosslinker for poly(vinyl alcohol) (PVA). Benefiting from the dual-phase fire-retardancy effect and the dynamic cross-linking effect, the addition of 5.0 wt% of HCPA enables PVA to achieve a desired self-extinguishment in combination with a high tensile strength of 133 MPa and a toughness of 112 MJ/m3. In addition, the as-prepared polymer material exhibits a high healing efficiency of over 90% (based on strength) if triggered by water. This proof-of-concept opens numerous opportunities for the creation of self-extinguishing, strong, tough, and self-healing polymers for many high-end applications in the above-mentioned industries. [ABSTRACT FROM AUTHOR]