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A team from the Schindler and Kulik labs report a visible-light-mediated approach that enables facile access to 1- and 2-azetine-based dimeric lactones of up to 30-membered ring macrocycles. This transformation occurs in one step and deviates from traditional macrolactonization methods. This new method may provide a unique avenue to access biologically interesting synthetic macrocycles. Article Link

A team from the Craig, Kulik, and Johnson labs report the mechanochemically coupled generation of hydrogen flouride (HF) from alkoxy-gem-difluorocyclopropane (gDFC) mechanophores derived from difluorocarbene addition to enol ethers. This latent source of HF resides within a polymer until released in response to a mechanical signal, at which point it be converted in situ to a flouride salt for use in self-immolative polymers, remodeled siloxane elastomers, vitrimer alteration, and degradable polymers. Article Link

A team from the Klausen, Craig, and Kulik labs report the synthesis of two new examples of 7- and 8-membered sila-cycloalkynes, as well as an investigation of their strain-promoted reactivity with azides. The results demonstrate that measurable angle-strain alone is insufficient for room-temperature cycloaddition, influencing design principles in an area broadly relevant to organic chemists and chemical biologists. Article Link

A team from the Moore, Craig, and Kulik labs detail a non-scissile mechanophore built from an 8-thiabicyclo[3.2.1]octane 8,8-dioxide (TBO) motif that releases one equivalent of sulfur dioxide (SO2) from each repeat unit. These comprehensive studies of TBO mechanophore provide a mechanically coupled mechanism of multi-SO2 release from one polymer chain, facilitating the translation of polymer mechanochemistry to potential biomedical applications. Article Link

A team from the Campos, Nelson, and Rubinstein labs report the use of carbazole-based thiuram disulfides (CTDs) that offer dual reactivity as photoactivated reshuffling linkages and iniferters under visible light irradiation. The fast response to visible light activation of the CTDs leads to temporal control of shape manipulation, healing, and chain extension in the polymer networks, despite the lack of optical transparency. Article Link

A team from the Gong and Craig labs embedded cyclobutane-based mechanophore crosslinkers in the first network of double network hydrogels and achieved efficient activation with 100% selectivity. These findings provide crucial design principles for achieving selective mechanophore activation and deepen our understanding of the damage mechanism within polymer networks when utilizing mechanophores as detectors. Article Link

A team from the Kalow and Kulik labs report the use of bifunctional aromatic thioesters as dynamic covalent cross-links in hydrogels, demonstrating that at physiologic pH in aqueous conditions, transthioesterification facilitates stress relaxation on the time scale of hundreds of seconds. This system exemplifies how dynamic cross-links that exchange through an associative mechanism enable tunable stress relaxation without altering stiffness. Article Link

A team from the Johnson and Kulik labs introduce the concept of leveraging “nested” supramolecular crosslinks to control bulk material functions. In these nested crosslinks two distinct supramolecular interactions exist in parallel and influence each other. In the future, this may leverage the vast existing body of known MOC host-guest binding properties to accelerate the creation of soft materials with exquisitely selective small-molecule-driven property changes for applications ranging from sensing to biomaterials. Article Link

A team from the Johnson lab and others at MIT collaborated with Université Paris-Saclay to propose a model where the relaxation of polymer gels in the dilute regime originates from elementary events in which the bonds connecting two neighboring cross-linkers all disconnect. The approach is simple enough to be extended to any cross-linker size and could thus be harnessed for the rational design of complex viscoelastic materials. Article Link

A team from the Steinmetz and Craig labs developed a novel swell-and-click method that led to successful VLP scaffold formation regardless of the viral load used. VLP-functionalized hydrogels were fabricated with viral concentrations as low as 0.1–1 mg/mL (0.01–0.1 % wt%) without compromising the scaffold stability on the process. The work introduces a novel methodology for the design of VLP-based hydrogels, which could facilitate the scalability of the fabrication process and move a significant step forward towards clinical translation of long-term VLP vaccination in cancer disease. Article Link

The Royal Society of Chemistry has elected to award the 2024 Materials Chemistry Horizon Prize to a team of NSF MONET researchers. The prize is awarded to the collaborative team behind the research demonstrating the potential and impact of embedded mechanochemical reactivity on the mechanical limits of cross-linked polymer networks. The prize consists of a professionally produced video showcasing the prize-winning work and its importance, and a trophy. Each collaborator also receives a certificate and individual recognition. RSC Award Page

A team from the Moore, Craig, and Kulik labs utilize a physical organic model to identify effective force constant and reaction energy as key molecular features that govern mechanochemical kinetics. These results demonstrate a general mechanistic framework for mechanochemical reactions under tensile force and provide a highly accessible tool for large-scale computational screening in the design of mechanophores. Article Link