We report the preparation of a furan polymer, poly(2,5-furandimethylene succinate) by means of a condensation reaction between bio-based monomers. A reversible Diels–Alder reaction between furan and maleimide groups allowed the formation of network polymers cross-linked by a bismaleimide. By controlling the amount of the bismaleimide, mechanical properties were varied widely. These network polymers healed well when their broken surfaces were activated by bismaleimide solutions or solvent. The polymers also displayed excellent self-healing ability without external stimulus. This polymer class offers a wide range of possibilities to produce materials from biomass that have both practical mechanical properties and healing ability. These materials have the potential to bring great benefits to our daily lives by enhancing the safety, performance, and lifetime of products.

Man-made glues often fail to stick in wet environments because of hydration-induced softening and dissolution. The wound healing process of a tunicate inspired the synthesis of gallol-functionalized copolymers as underwater adhesive. Copolymers bearing three types of phenolic groups, namely, phenol, catechol, and gallol, were synthesized via the methoxymethyl protection/deprotection route. Surprisingly, the newly synthesized copolymers bearing gallol groups exhibited stronger adhesive performances (typically 7× stronger in water) than the widely used catechol-functionalized copolymers under all tested conditions (in air, water, seawater, or phosphate-buffered saline solution). The higher binding strength was ascribed to the tridentate-related interfacial interaction and chemical cross-linking. Moreover, gallol-functionalized copolymers adhered to all tested surfaces including plastic, glass, metal, and biological material. In seawater, the performance of gallol-functionalized copolymer even exceeds the commercially available isocyanate-based glue. The insights from this study are expected to help in the design of biomimetic materials containing gallol groups that may be utilized as potential bioadhesives and for other applications. The results from such a kind of comparable study among phenol, catechol, and gallol suggests that tridentate structure should be better than bidentate structure for bonding to the surface.

Four commercially available samples of bacterial poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] containing from 6.5 to 21.8 mol % 3HV have been fractionated by chloroform/reheptane mixed solvent. They have been separated into several fractions with wide composition ranges. These results show that the composition distribution of as received bacterial P(3HB-co-3HV)s is extremely broad and/or has many peaks over a wide composition range. The effects of the complex composition distribution on physical properties have been analyzed through the comparison of melting and crystallization behavior between samples before and after fractionation. Three as received P(3HB-co-3HV)s show the behavior corresponding to the average composition in spite of their complex composition distribution. The melting temperature and spherulite growth rate correspond to the values expected from extrapolation of the data from the fractionated samples. In these copolyesters, cocrystallization of the chains within the wide composition range occurs. However, one as received P(3HB-co-3HV) has a higher melting temperature and faster growth rate than might be expected. The apparent crystallization behavior corresponds to that of P(3HB-co-3HV) with lower 3HV content. These data suggest that only the component chains of relatively low 3HV content are crystallized in this as received P(3HB-co-3HV). The crystallization of components of high 3HV content is significantly restricted. The extremely broad composition distribution of this copolyester affects the crystallization (melting) behavior.

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Incorporating reversible sacrificial bonds in network polymers not only toughens these materials but also endows them with self‐recoverability. However, self‐recoverability is only realized for dispersed energy less than 10 MJ m−3. It remains a challenge to achieve simultaneous high stretchability, toughness, and recoverability. Here, inspired by the structure of mussel byssus cuticles, a new design strategy is proposed and demonstrated to improve both the toughness and self‐recoverability of elastomers by introducing a microphase‐separated structure with different physical crosslink densities. This structure can be achieved using a carefully designed comonomer sequence distribution of hydrogen bonding units in an ABA‐type triblock copolymer. The A blocks form hard domains with dense crosslinking that prevents macroscopic deformation, while the B blocks form a softer matrix with sparse and dynamic crosslinks that serve as sacrificial bonds. This elastomer exhibits high toughness (≈62 MJ m−3), self‐healing, and most notably, excellent self‐recovery (recovery against 650% elongation and 17 MPa tensile stress with a dissipated energy >27 MJ m−3 at room temperature). This combination of toughness, self‐healing, and self‐recovery expands the range of applications of these advanced dynamic materials.