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The aerobic composting and anaerobic digestion of plastics is a promising route to recovering the multidimensional value from biodegradable single-use plastics. At present, the collection, separation, and management of biodegradable plastic waste are extremely challenging, and the majority of these plastics still end up in landfills or incineration facilities. This is because not all biodegradable plastics can be treated using organic waste management options (composting). In addition, end-users at a domestic and industrial level are often unaware of the compostability potential of biodegradable plastics, which results in the mismanagement of these types of plastic. A greater understanding of the compostability of biodegradable plastics will generate the required knowledge base for interventions that support their market penetration, use, and proper management. In this review, we clarify the concepts of biodegradability and compostability in bioplastics, in particular commercial synthetic biopolyesters, which have increasing technical and economic importance, and discuss how macromolecular design, blending, and additives can be used to modify their compostability. Future trends on the uptake of compostable and biodegradable bioplastics are also discussed.

Engineering materials and devices can be damaged during their service life as a result of mechanical fatigue, punctures, electrical breakdown, and electrochemical corrosion. This damage can lead to unexpected failure during operation, which requires regular inspection, repair, and replacement of the products, resulting in additional energy consumption and cost. During operation in challenging, extreme, or harsh environments, such as those encountered in high or low temperature, nuclear, offshore, space, and deep mining environments, the robustness and stability of materials and devices are extremely important. Over recent decades, significant effort has been invested into improving the robustness and stability of materials through either structural design, the introduction of new chemistry, or improved manufacturing processes. Inspired by natural systems, the creation of self‐healing materials has the potential to overcome these challenges and provide a route to achieve dynamic repair during service. Current research on self‐healing polymers remains in its infancy, and self‐healing behavior under harsh and extreme conditions is a particularly untapped area of research. Here, the self‐healing mechanisms and performance of materials under a variety of harsh environments are discussed. An overview of polymer‐based devices developed for a range of challenging environments is provided, along with areas for future research.

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While the fascinating field of soft machines has grown rapidly over the last two decades, the materials they are constructed from have remained largely unchanged during this time. Parallel activities have led to significant advances in the field of dynamic polymer networks, leading to the design of three‐dimensionally cross‐linked polymeric materials that are able to adapt and transform through stimuli‐induced bond exchange. Recent work has begun to merge these two fields of research by incorporating the stimuli‐responsive properties of dynamic polymer networks into soft machine components. These include dielectric elastomers, stretchable electrodes, nanogenerators, and energy storage devices. In this Minireview, we outline recent progress made in this emerging research area and discuss future directions for the field.

The actuation and energy-harvesting performance of dielectric elastomers are strongly related to their intrinsic electrical and mechanical properties. For future resilient smart transducers, a fast actuation response, efficient energy-harvesting performance, and mechanical robustness are key requirements. In this work, we demonstrate that poly­(styrene-butadiene-styrene) (SBS) can be converted into a self-healing dielectric elastomer with high permittivity and low dielectric loss, which can be deformed to large mechanical strains; these are key requirements for actuation and energy-harvesting applications. Using a one-step click reaction at room temperature for 20 min, methyl-3-mercaptopropionate (M3M) was grafted to SBS and reached 95.2% of grafting ratios. The resultant M3M–SBS can be deformed to a high mechanical strain of 1000%, with a relative permittivity of εr = 7.5 and a low tan δ = 0.03. When used in a dielectric actuator, it can provide 9.2% strain at an electric field of 39.5 MV m–1 and can also generate an energy density of 11 mJ g–1 from energy harvesting. After being subjected to mechanical damage, the self-healed elastomer can recover 44% of its breakdown strength during energy harvesting. This work demonstrates a facile route to produce self-healing, high permittivity, and low dielectric loss elastomers for both actuation and energy harvesting, which is applicable to a wide range of diene elastomer systems.

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