The current global materials economy has long been inefficient due to unproductive reuse and recycling efforts. Within the wider materials portfolio, plastics have been revolutionary to many industries but they have been treated as disposable commodities leading to their increasing accumulation in the environment as waste. The field of chemistry has had significant bearing in ushering in the current plastics industry and will undoubtedly have a hand in transforming it to become more sustainable. Existing approaches include the development of synthetic biodegradable plastics and turning to renewable raw materials in order to produce plastics similar to our current petrol-based materials or to create new polymers. Additionally, chemists are confronting the environmental crisis by developing alternative recycling methods to deal with the legacy of plastic waste. Important emergent technologies, such as catalytic chemical recycling or upcycling, have the potential to alleviate numerous issues related to our current and future refuse and, in doing so, help pivot our materials economy from linearity to circularity.

The importance of stereochemistry to the function of molecules is generally well understood. However, to date, control over stereochemistry and its potential to influence properties of the resulting polymers are, as yet, not fully realised. This review focuses on the state-of-the-art with respect to how stereochemistry in polymers has been used to influence and control their physical and mechanical properties as well as begin to control their function. A brief overview of the synthetic methodology by which to access these materials is included, with the main focus directed towards stereochemical control over properties such as mechanical, biodegradation and conductivity. Additionally, the advances being made towards enantioseparation, enantioselective catalyst supports and stereo-directed transitions are discussed. Finally, we also consider the opportunities that the rich stereochemistry of sustainably-sourced monomers could offer in this field. Where possible, parallels and general design principles are drawn together to identify opportunities and limitations that these approaches may present in their effects on materials properties, performance and function.

The 1,4-conjugate addition reaction between activated alkynes or acetylenic Michael acceptors and nucleophiles (i.e., the nucleophilic Michael reaction) is a historically useful organic transformation. Despite its general utility, the efficiency and outcomes can vary widely and are often closely dependent upon specific reaction conditions. Nevertheless, with improvements in reaction design, including catalyst development and an expansion of the substrate scope to feature more electrophilic alkynes, many examples now present with features that are congruent with Click chemistry. Although several nucleophilic species can participate in these conjugate additions, ubiquitous nucleophiles such as thiols, amines, and alcohols are commonly employed and, consequently, among the most well developed. For many years, these conjugate additions were largely relegated to organic chemistry, but in the last few decades their use has expanded into other spheres such as bioorganic chemistry and polymer chemistry. Within these fields, they have been particularly useful for bioconjugation reactions and step-growth polymerizations, respectively, due to their excellent efficiency, orthogonality, and ambient reactivity. The reaction is expected to feature in increasingly divergent application settings as it continues to emerge as a Click reaction.

Thiol–ene ‘click’ reactions between terpenes and a four-arm thiol were utilized to produced thermoset 3D printed structures using vat photopolymerisation.

Controlled synthesis of conjugated polymers with functional side chains is of great importance, affording welldefined optoelectronic materials possessing enhanced stability and tunability as compared to their alkyl-substituted counterparts. Herein, a chain-growth Suzuki polycondensation of an ester-functionalized thiophene is described using commercially available nickel precatalysts. Model compound studies were used to identify suitable catalysts, and these experiments provided guidance for the polymerization of the ester-substituted monomer. This is the first report of nickel-catalyzed Suzuki cross-coupling for catalyst-transfer polycondensation, and to further illustrate the versatility of this method, block and alternating copolymers with 3-hexylthiophene were synthesized. The presented protocol should serve as an entry point into the synthesis of other electron-deficient polymers and donor−acceptor copolymers with controlled molecular weights and low dispersity.