We examine the effect of alpha-cyclodextrin (αCD) on the crystallization of poly(ethylene glycol) (PEG) [poly(ethylene oxide), PEO] in low-molar-mass polymers, with M w = 1000, 3000, or 6000 g mol-1. Differential scanning calorimetry (DSC) and simultaneous synchrotron small-/wide-angle X-ray scattering (SAXS/WAXS) show that crystallization of PEG is suppressed by αCD, provided that the cyclodextrin content is sufficient. The PEG crystal structure is replaced by a hexagonal mesophase of αCD-threaded polymer chains. The αCD threading reduces the conformational flexibility of PEG and, hence, suppresses crystallization. These findings point to the use of cyclodextrin additives as a powerful means to tune the crystallization of PEG (PEO), which, in turn, will impact bulk properties including biodegradability.

Even though heavy and transition metals originated in the earth's crust, the significant human exposure and environmental pollution consequences of anthropogenic activities include industrial production and waste, mining and smelting operations, and agricultural and domestic usage of metals. Because of their nonbiodegradable nature, heavy metal ions such as Cu2+ accumulate very quickly in plants and edible animals, ultimately ending up in the human food cycle. Therefore, to nullify the detrimental effects of Cu2+ ions for the sake of the environment and living organisms, we are motivated to design a sensor molecule that can not only detect Cu2+ ions but also remove them selectively from the water medium. To detect the Cu2+ ions, we synthesized a monomer (NCu) and its biodegradable caprolactone-based polymer (PNCu). It was observed that both NCu and PNCu showed higher selectivity toward Cu2+ ions by changing the color from colorless to yellow, with a limit of detection value of 29 nM and 0.3 μM. Furthermore, removing the Cu2+ ions from the water solution was also accomplished by introducing the hydrophobicity of the polymer (PNCu) through the ring-opening polymerization process. Due to increased hydrophobicity, the polymer produced a yellow color precipitate upon adding Cu2+ ions to the solution; thus, removal of the metal ion is possible using our designed polymer and its detection ability. We checked the removal efficiency of our polymer by using UV-vis spectroscopy and EDX analysis, which indicated that almost all of the copper is removed by our polymer. Therefore, to our knowledge, this is the first biodegradable caprolactone-based polymer for colorimetric turn-on detection and separation of the Cu2+ ions from the water.

Herein, we disclose a unique and selective reagent for the cleavage of stable azaylides prepared by the nonhydrolysis Staudinger reaction, enabling the on-demand unfolding of robust single-chain nanoparticles (SCNPs). SCNPs with promising use in catalysis, nanomedicine, and sensing are obtained through intrachain folding of discrete synthetic polymer chains. The unfolding of SCNPs involving reversible interactions triggered by a variety of external stimuli (e.g., pH, temperature, light, and redox potential) or substances (e.g., competitive reagents, solvents, and anions) is well known. Conversely, methods for the unfolding (i.e., intrachain disassembly) of SCNPs with stronger covalent interactions are scarce. We show that trimethylsilanol (Me3SiOH) triggers the efficient unfolding of robust "Staudinger" SCNPs with stable azaylide (-N=P-) moieties as intrachain cross-linking units showing exceptional stability toward water, air, and CS2, a standard reagent for azaylides. As a consequence, Me3SiOH arises as a rare, exceptional, and valuable reagent for the cleavage of stable azaylides prepared by the nonhydrolysis Staudinger reaction.

Electrically conductive hydrogels represent an innovativeplatformfor the development of bioelectronic devices. While photolithographytechnologies have enabled the fabrication of complex architectureswith high resolution, photoprinting conductive hydrogels is stilla challenging task because the conductive polymer absorbs light whichcan outcompete photopolymerization of the insulating scaffold. Inthis study, we introduce an approach to synthesizing conductive hydrogelsin one step. Our approach combines the simultaneous photo-cross-linkingof a polymeric scaffold and the polymerization of 3,4-ethylene dioxythiophene(EDOT), without additional photocatalysts. This process involves thecopolymerization of photo-cross-linkable coumarin-containing monomerswith sodium styrenesulfonate to produce a water-soluble poly(styrenesulfonate-co-coumarin acrylate) (P(SS-co-CoumAc))copolymer. Our findings reveal that optimizing the [SS]:[CoumAc] ratioat 100:5 results in hydrogels with the strain at break up to 16%.This mechanical resilience is coupled with an electronic conductivityof 9.2 S m–1 suitable for wearable electronics.Furthermore, the conductive hydrogels can be photopatterned to achievemicrometer-sized structures with high resolution. The photo-cross-linkedhydrogels are used as electrodes to record stable and reliable surfaceelectromyography (sEMG) signals. These novel photo-cross-linkablepolymers combined with one-pot PEDOT (poly-EDOT) polymerization openpossibilities for rapidly prototyping complex bioelectronic devicesand creating custom-designed interfaces between electronics and biologicalsystems.

Synthetic polymers are highly customizable with tailored structures and functionality, yet this versatility generates challenges in the design of advanced materials due to the size and complexity of the design space. Thus, exploration and optimization of polymer properties using combinatorial libraries has become increasingly common, which requires careful selection of synthetic strategies, characterization techniques, and rapid processing workflows to obtain fundamental principles from these large data sets. Herein, we provide guidelines for strategic design of macromolecule libraries and workflows to efficiently navigate these high-dimensional design spaces. We describe synthetic methods for multiple library sizes and structures as well as characterization methods to rapidly generate data sets, including tools that can be adapted from biological workflows. We further highlight relevant insights from statistics and machine learning to aid in data featurization, representation, and analysis. This Perspective acts as a "user guide" for researchers interested in leveraging high-throughput screening toward the design of multifunctional polymers and predictive modeling of structure-property relationships in soft materials.

Cross-coupling polymerizations have fundamentally changed the field of conjugated polymers (CPs) by expanding the scope of accessible materials. Despite the prevalence of cross-coupling in CP synthesis, almost all polymerizations rely on mononuclear Ni or Pd catalysts. Here, we report a systematic exploration of mono- and dinuclear Fe and Ni precatalysts with a pyridine diimine ligand scaffold for Kumada cross-coupling polymerization of a donor thiophene and an acceptor benzotriazole monomers. We observe that variation of the metal identity from Ni to Fe produces contrasting polymerization mechanisms, while complex nuclearity has a minimal impact on reactivity. Specifically, Fe complexes appear to catalyze step-growth Kumada polymerizations and can readily access both Csp2-Csp3 and Csp2-Csp2 cross-couplings, while Ni complexes catalyze chain-growth polymerizations and predominantly Csp2-Csp2 cross-couplings. Thus, our work sheds light on important design parameters for transition metal complexes used in cross-coupling polymerizations, demonstrates the viability of iron catalysis in Kumada polymerization, and opens the door to novel polymer compositions.

Polyproline is a material of great interest in biomedicinedueto its helical scaffold of structural importance in collagen and mucinsand its ability to gel and to change conformations in response totemperature. Appending of function-modulating chemical groups to sucha material is desirable to diversify potential applications. Here,we describe the synthesis of high-molecular-weight homo, block, andstatistical polymers of azide-functionalized proline. The azide groupsserved as moieties for highly efficient click-grafting, as stabilizersof the polyproline PPII helix, and as modulators of thermoresponsiveness.Saccharides and ethylene glycol were utilized to explore small-moleculegrafting, and glutamate polymers were utilized to form polyelectrolytebottlebrush architectures. Secondary structure effects of both theazide and click modifications, as well as lower critical solutiontemperature behavior, were characterized. The polyazidoprolines andclick products were well tolerated by live human cells and are expectedto find use in diverse biomedical applications.

A grand challenge in polymer science lies in the predictive design of new polymeric materials with targeted functionality. However, de novo design of functional polymers is challenging due to the vast chemical space and an incomplete understanding of structure-property relations. Recent advances in deep generative modeling have facilitated the efficient exploration of molecular design space, but data sparsity in polymer science is a major obstacle hindering progress. In this work, we introduce a vast polymer database known as the Open Macromolecular Genome (OMG), which contains synthesizable polymer chemistries compatible with known polymerization reactions and commercially available reactants selected for synthetic feasibility. The OMG is used in concert with a synthetically aware generative model known as Molecule Chef to identify property-optimized constitutional repeating units, constituent reactants, and reaction pathways of polymers, thereby advancing polymer design into the realm of synthetic relevance. As a proof-of-principle demonstration, we show that polymers with targeted octanol-water solubilities are readily generated together with monomer reactant building blocks and associated polymerization reactions. Suggested reactants are further integrated with Reaxys polymerization data to provide hypothetical reaction conditions (e.g., temperature, catalysts, and solvents). Broadly, the OMG is a polymer design approach capable of enabling data-intensive generative models for synthetic polymer design. Overall, this work represents a significant advance, enabling the property targeted design of synthetic polymers subject to practical synthetic constraints.

The encoded precision of biological polymers enables a few simple monomers (e.g., four nucleotides in nucleic acids) to create complex macromolecular structures that accomplish a myriad of functions. Similar spatial precision in synthetic polymers and oligomers can be harnessed to create macromolecules and materials with rich and tunable properties. Recent exciting advances in iterative solid- and solution-phase synthetic strategies have led to the scalable production of discrete macromolecules, which in turn has enabled the study of sequence-dependent material properties. Our recent example of a scalable synthetic strategy using inexpensive vanillin-based monomers to create sequence-defined oligocarbamates (SeDOCs) enabled the preparation of isomeric oligomers with different thermal and mechanical properties. We show that unimolecular SeDOCs also exhibit sequence-dependent dynamic fluorescence quenching that persists from solution to the solid phase. We detail the evidence for this phenomenon and show that changes in fluorescence emissive properties are dependent on macromolecular conformation, which in turn is driven by sequence.

Living anionic polymerization will soon celebrate 70 years of existence. This living polymerization is considered the mother of all living and controlled/living polymerizations since it paved the way for their discovery. It provides methodologies for synthesizing polymers with absolute control of the essential parameters that affect polymer properties, including molecular weight, molecular weight distribution, composition and microstructure, chain-end/in-chain functionality, and architecture. This precise control of living anionic polymerization generated tremendous fundamental and industrial research activities, developing numerous important commodity and specialty polymers. In this Perspective, we present the high importance of living anionic polymerization of vinyl monomers by providing some examples of its significant achievements, presenting its current status, giving several insights into where it is going (Quo Vadis) and what the future holds for this powerful synthetic method. Furthermore, we attempt to explore its advantages and disadvantages compared to controlled/living radical polymerizations, the main competitors of living carbanionic polymerization.