Reclaiming undamaged carbon fiber from thermoset composites requires chemical recycling methods that leverage complete deconstruction of the polymer matrix. Cleavable comonomers enable chemical recycling of poly(dicyclopentadiene) (pDCPD) composites, but current systems suffer from reduced glass transition temperature (Tg), limiting application. Here, we investigate the effect of cleavable comonomer loading and cleavable crosslinker chemistry on network formation, thermomechanical properties, and fiber recovery in frontally cured pDCPD composites. All formulations fully deconstructed in acid and recovered fibers ranged from pristine to variably contaminated depending on crosslinker chemistry. Reducing backbone-cleaving comonomer content and introducing cleavable crosslinkers raised composite Tg to 126-138 degrees C compared to 105 degrees C previously reported in deconstructable pDCPD composites. Although the cleavable crosslinkers increased Tg in unreinforced polymers to 150-160 degrees C, the fiber-reinforced composite Tg remained lower due to under-curing and interactions between the crosslinkers and the fiber surface. Increasing polymerization initiator loading improved comonomer conversion and yielded a deconstructable composite with Tg = 151 degrees C, approaching the performance of nondeconstructable pDCPD composites (Tg = 161 degrees C). This work clarifies how cleavable comonomer and crosslinker chemistry governs curing, thermomechanical performance, and reclaimed reinforcement quality, and the results highlight the need for more robust cleavable comonomers to realize multigenerational composite materials without sacrificing thermomechanical performance.

Polydicyclopentadiene (pDCPD) is a high-performance thermoset whose unusual oxidative sensitivity has long been recognized but is not mechanistically understood. Here we identify singlet oxygen (1O2) as the primary oxidant and the pendant cyclopentene ring as the primary site of reactivity that together drive the intrinsic oxidative degradation of pDCPD. Controlled 1O2 generation, model compound studies, and weathering experiments reveal a chemoselective oxy-ene pathway that selectively converts cyclopentene units into cyclopent-2-en-1-ones and initiates allylic-hydroperoxide-driven cross-linking. In contrast, main-chain alkene models and studies on pH2DCPD─in which the cyclopentene unit is saturated to suppress oxy-ene reactivity─show that the main-chain alkene follows a slower β-scission pathway. These mechanistic distinctions explain the long-observed oxidative instability of pDCPD and clarify why polymers lacking the pendant cyclopentene, such as pH2DCPD, offer improved resistance to oxidative aging. Guided by this insight, oligo-DCPD fragments are transformed into polar, benzyl-acrylate-miscible, polyfunctional additives whose enone groups enable tunable cross-linking during radical acrylate polymerization. Together, these results connect the molecular origin of pDCPD oxidation to both monomer design principles and selective macromolecular editing strategies.

Peptoids are structural analogs of peptides in which side chains are appended to the backbone nitrogen rather than the α-carbon. The sequence-defined modularity of peptoids enables precise control over structure-function relationships, enabling applications in energy storage and biomedical materials. Despite recent progress, the role of sequence and conformation on electron transport in peptoid molecules is not fully understood. Here, we synthesize a library of peptoid oligomers and characterize their molecular electronic properties using the scanning tunneling microscope-break junction (STM-BJ) technique. Our results show well-defined electron transport behavior for peptoid sequences containing aromatic side groups lacking hydrogen bonds (H-bonds) and without chemical substitutions at the N-Cα position. This behavior fundamentally differs from electron transport in peptides, where H-bond interactions give rise to higher conductance states. All-atom molecular dynamics (MD) simulations are used to understand the conformational heterogeneity of peptoids, and molecular conformations obtained from MD simulations are used in quantum mechanical calculations based on the nonequilibrium Green's function-density functional theory (NEGF-DFT) formalism. In all cases, computational results are in reasonable qualitative agreement with experiments. Our work demonstrates that the conductance behavior of peptoids depends on monomer identity, including side-chain aromaticity and substitution at the N-Cα position. Overall, this work provides new insights into the structure-function relationships governing electron transport in peptoid-based materials and establishes design rules for peptoid-based molecular junctions.

Mechanochemical activation has been extensively investigated in solutions and soft polymeric materials, where force transmission along stretched chains dominates the response. In contrast, activation behavior in higher-modulus, glassy thermosets remains poorly understood, and the role of the material environment itself has not been systematically quantified. Here, we investigate spiropyran (SP) mechanophores incorporated into a high-performance poly(dicyclopentadiene) (pDCPD) network fabricated directly by polymerization into its final form. This chemically faithful synthesis preserves network integrity and enables the quantitative analysis of mechanophore activation under tensile and compressive loading. We find that activation is absent in the elastic regime and emerges only beyond the macroscopic yield point. These results demonstrate that the mechanochemical response in this glassy network is governed by deformation and irreversible segmental mobility rather than tension magnitude alone, establishing motion-induced activation as distinct from the behavior previously observed in soft materials. The SP-pDCPD system thus provides a quantitative framework for understanding mechanochemical activation in high-performance glassy polymers.

Thermoset plastics underpin structural materials, electronics, and transportation, yet their permanent covalent networks make recycling difficult.1–5 Existing recycling strategies for high‑Tg engineering applications that incorporate exchangeable6–15 or cleavable bonds16–20 often compromise stiffness, creep resistance, or thermal stability, and typically treat covalent junctions as the primary load-bearing elements.21,22 Rather than considering recycling as the recovery of degraded networks, here we construct thermosets in which high mechanical performance arises predominantly from dense chain entanglements, while only a sparse fraction of trigger-cleavable junctions preserves network connectivity. Long, rigid, entangled polyolefin backbones generated by frontal polymerization form high-Tg, glassy polymers with high stiffness, high toughness, and excellent creep suppression, yet fully deconstruct to soluble, linear oligomers. Programming oligomer length and end-group chemistry enables their reuse as re-entangling building blocks that regenerate thermosets with generation-invariant thermomechanical properties, including in high-temperature fiber reinforced composite matrices and additively manufactured structures. By demonstrating that load-bearing in high‑Tg engineering thermosets can be delivered primarily by entangled strands while sparse cleavable junctions preserve connectivity, this strategy maintains network topology across generations and establishes an entanglement-dominated design principle for regenerable, high-performance networks based on entanglement-dominated architectures.

Frontal ring-opening metathesis polymerization (FROMP) enables energy- and time-efficient manufacturing by harnessing the exothermic ring-opening of strained cyclic olefins to sustain self-propagating reaction fronts. However, identifying suitable monomers is challenging, as stable front propagation depends on the complex interplay between the thermodynamic driving force and the coupled kinetics of reactions and transport. Here, we present a multi-scale screening framework to predict macroscopic front behavior from molecular structure. Quantum chemical calculations and physicochemical relations are used to approximate monomer-level kinetic and thermodynamic descriptors, which then parameterize a mechanism-based reaction– diffusion model to simulate front propagation. The approach is validated against 35 experimentally characterized monomers, successfully classifying 26 cases and capturing 96% of known FROMP-active cases. When successfully applied to a combinatorial library of 1,154 cycloaddition-derived monomers, the framework identifies 399 promising candidates across diverse structural families. Our work provides a predictive foundation for rational FROMP monomer selection and design, broadening the scope of materials accessible through frontal polymerization.

Precise control over molecular length is essential for understanding how conjugated materials develop supramolecular chirality, liquid-crystalline order, and electronic function. Here, we synthesize a monodisperse series of pyridine-flanked diketopyrrolopyrrole-bithiophene (PyDPP-2T) oligomers (Monomer, Dimer, Trimer, Pentamer, and Heptamer) using a modular Stille/direct arylation polymerization (DArP) strategy. A sharp transition emerges between Trimer and Pentamer, beyond which chiral liquid-crystalline phases form in absence of molecular chirality. Pentamer, Heptamer, and Polymer exhibit distinct length-dependent chiral mesophases (helicoidal smectic, cholesteric, and nematic twist-bend) where positional order gives way to increasingly complex orientational order as the molecular contour length exceeds the persistence length. Electrical measurements show a monotonic increase in conductivity with backbone length, and Heptamer achieves polymer-level performance despite its discrete structure. These findings identify molecular length as a programmable design variable for engineering hierarchical order and function in π-conjugated materials.

Thermoset plastics underpin structural materials, electronics and transportation, yet the permanent covalent networks that prevent flow and provide dimensional stability also make them difficult to recycle without sacrificing performance. Here we show that high-performance thermosets can be built around dense chain entanglements, the physical interlacing of long polymer strands, rather than dense permanent crosslinks, with only a small number of selectively cleavable junctions preserving connectivity. Long, rigid, entangled polyolefin backbones generated by frontal polymerization form glassy polymers with high stiffness, high toughness and excellent creep suppression yet can be fully deconstructed into soluble, linear oligomers. Varying oligomer length and end-group chemistry enables their reuse as re-entangling building blocks that regenerate thermosets with thermal and mechanical properties that remain unchanged across generations. The strategy further extends to high-temperature fibre-reinforced composite matrices and additively manufactured structures, establishing chain entanglement as a design principle for durable, regenerable thermosets.

Lignin is an abundant biofeedstock that holds great potential for producing renewable organic chemicals, but its effective valorization is difficult due to low conversion rates and the need for harsh reaction conditions, which impact selectivity. Here, we introduce an alternative to catalyzed thermochemical and electrochemical methods consisting of a fast one-step (∼20 min) uncatalyzed use of sonicated emulsive water microdroplets (SEWMs) to efficiently deconstruct Kraft lignin (∼14.2 kDa). We converted Kraft lignin selectively and in high yield ( ∼ 56% ± 5%) into SEMILL-A (∼656 Da), composed of possible structural isomers of a redox-active small molecule to which we assigned a structure consisting of substituted nitrophenyl units attached to a coumarin dicarboxylic acid core. Characterization of SEMILL-A was carried out using infrared spectroscopy, 1D and 2D nuclear magnetic resonance spectroscopy, high-resolution mass spectrometry, chromatography, and electrochemical analysis. We show the possibility of SEWMs to activate C─C bond cleavage and to facilitate reductive nitration in Kraft lignin and a model compound. Our study highlights a distinctive reactive environment within SEWMs where sonochemical excitation and redox microdroplet chemistry synergistically enable novel deconstructive pathways for biofeedstock valorization.

Thermoset materials are indispensable in high-performance applications due to their exceptional mechanical properties, chemical resistance, and thermal stability. However, their cross-linked structure poses significant challenges for sustainable manufacturing and end-of-life reprocessing. Herein, we present a novel approach to regenerate high-performance polydicyclopentadiene (pDCPD) thermoset materials through a one-pot deconstruction-reactivation strategy enabled by an "activatable repeat unit", norbornene-furan (NBF). The pendant furyl ring of NBF remains intact during the initial curing reaction via frontal ring-opening metathesis polymerization (FROMP) and retains its reactivity for subsequent Diels-Alder cycloaddition with the in situ generated benzyne. Deconstruction-reactivation proceeds in one pot to effectively recover the activated oligomers for further FROMP curing, thereby completing the circular workflow. The regenerated materials demonstrate retention of key properties, including glass transition temperature (T g), stiffness, and yield strength, while maintaining their deconstruction capability. This strategy provides a sustainable framework for thermoset material design and regeneration, addressing critical challenges in material circularity and environmental impact.

Advancing mechanoresponsive materials require novel mechanophores, though clear and structured design guidelines are still emerging. In this work, we present a systematic workflow aimed at facilitating the design and discovery of new mechanophores. By integrating the classic iso-metrical CoGEF approach with our innovative iso-tensional Tension Model of Bond Activation (TMBA) simulation, the workflow described herein enables comprehensive evaluation of mechanophore candidates prior to experimental implementation, with a practical case study included for detailed illustration. This predictive capability allows computational screening, efficient identification and filtering away unexpected issues while providing valuable insights for potential structural optimization.

Metal-binding proteins have the exceptional ability to facilitate long-range electron transport in nature. Despite recent progress, the sequence-structure-function relationships governing electron transport in heme-binding peptides and protein assemblies are not yet fully understood. In this work, the electronic properties of a series of heme-binding peptides inspired by cytochrome bc 1 are studied using a combination of molecular electronics experiments, molecular modeling, and simulation. Self-assembled monolayers (SAMs) are prepared using sequence-defined heme-binding peptides capable of forming helical secondary structures. Following monolayer formation, the structural properties and chemical composition of assembled peptides are determined using atomic force microscopy and X-ray photoelectron spectroscopy, and the electronic properties (current density-voltage response) are characterized using a soft contact liquid metal electrode method based on eutectic gallium-indium alloys (EGaIn). Our results show a substantial 1000-fold increase in current density across SAM junctions upon addition of heme compared to identical peptide sequences in the absence of heme, while maintaining a constant junction thickness. These findings show that amino acid composition and sequence directly control enhancements in electron transport in heme-binding peptides. Overall, this study demonstrates the potential of using sequence-defined synthetic peptides inspired by nature as functional bioelectronic materials.

Polydicyclopentadiene, p(DCPD), is a high‐performance thermoset valued for its exceptional toughness, strength, and stiffness. When copolymerized with 1,5‐cyclooctadiene (COD), its mechanical properties can be tuned from glassy to rubbery at room temperature. While frontal polymerization enables a rapid and energy‐efficient route to 3D print DCPD‐based materials, challenges such as ink shelf life and gravitational distortion, especially in direct ink writing of soft COD‐rich formulations, must be considered. Here, a complementary chemical strategy is presented, embedded 3D printing, that enables localized in situ polymerization of printed DCPD/COD inks within a reactive support matrix. The matrix provides both physical support and a reservoir of chemical activator, which diffuses into the ink, activates a latent bis(N‐heterocyclic carbene) Ru precatalyst, and initiates ring‐opening metathesis polymerization. Curing begins at the ink–matrix interface and propagates inward via diffusion, stabilizing the interface and preventing capillary‐driven deformation regardless of the matrix yield stress. This approach eliminates the need for cold storage, external curing, or photoinitiation, significantly expanding the processing window. Using this method, diverse thermosetting and elastomeric architectures are fabricated with features as small as 5 µm and aspect ratios of 100, including interlinked chains, shallow spherical shells exhibiting snap‐through buckling, and hair‐like fin arrays inaccessible through traditional techniques.

Emergent patterns in biological systems arise through dissipative processes that balance reaction and transport phenomena, producing highly functional properties from self-regulating mechanisms. Synthetic fabrication, by contrast, often relies on user-controlled, multistep methods that lack the self-organizing capabilities of natural systems. Inspired by nature, we sought chemical systems that integrate strongly coupled reaction and transport phenomena, identifying frontal ring-opening metathesis polymerization (FROMP) as a method capable of creating diverse forms and functions through reactive processing. By employing discrete molecular initiators, FROMP allows precise control of key reaction steps-inhibition, initiation, and propagation. Using an integrated computational and experimental framework, we uncover how near-equilibrium inhibition dynamics, coupled with far-from-equilibrium reaction kinetics, drive pattern formation in frontally polymerized synthetic materials. We propose the concept of equilibrium-gated pattern formation, demonstrating how initiator chemistry can be tuned to achieve programmable macroscale properties. Our study reveals a surprising insight: Emergent behavior in FROMP systems arises from the inhibition-dominated regime of resin composition, expanding prior observations that such behavior is confined to a narrow compositional space near the boundary between front quenching and uniform front propagation. We identify a broader compositional window, far from the quenching regime, where emergent behavior reliably manifests. This expanded design space significantly enhances the operational flexibility of reactive systems and their capacity for self-organization. These insights provide a roadmap for designing bioinspired materials with self-organizing capabilities, unlocking possibilities in synthetic manufacturing.

The increasing demand for carbon fibre-reinforced polymer composites with polyolefin thermoset matrices will lead to the generation of large volumes of low molecular weight waste oligomers during the fibre recovery process. To address this challenge, we present a cooperative electrolytic dual C–H bond functionalization strategy for the one-step installation of two key functional groups essential for dynamic linkages of these deconstructed oligomers. Through direct competition studies, we reveal the predominance of tertiary allylic C–H activation along the complex, branched oligomer backbone. The resulting difunctionalized oligomers form covalently adaptable networks with exceptional circularity. By establishing a sustainable pathway for upcycling deconstructed oligomers from carbon fibre-reinforced polymer fibre recovery, this strategy introduces thermoset materials derived directly from waste. It advances sustainable manufacturing practices, contributing to a net-zero waste synthetic ecosystem, and highlights the prospects of mediated electrolysis in macromolecular transformations. A cooperative electrolytic strategy is designed, enabling dual C–H functionalization of deconstructed polyolefin oligomers, converting carbon fibre-reinforced polymer waste into adaptive materials. This approach forms covalently adaptable networks and establishes electrochemical backbone editing as a versatile platform for advanced polymer design and functionalization.

Terminal anchor groups play a key role in controlling the stability and electronic properties of molecular junctions. Single molecule junctions typically consist of two terminal anchors linking organic molecules to metal electrodes. Here, we show that p -terphenyl derivatives containing only a single terminal anchor exhibit molecular conductance similar to junctions with two terminal anchors, which arises due to in situ electrochemical Au-C bond formation due to a single electron oxidation event at the electrode. A set of p -terphenyl derivatives with one terminal anchor was prepared using automated chemical synthesis and subsequently characterized using single molecule electronics experiments, bulk spectroscopy, electrochemistry, molecular dynamics (MD) simulations, and non-equilibrium Green’s function-density functional theory (NEGF-DFT) calculations. Our results show that 4-amino- p -terphenyl (PPP) exhibits a distinct and well-defined high conductance state that is greatly diminished or absent in other p -terphenyl derivatives with single terminal anchors, whereas a low conductance state is observed in all amino- p -terphenyl derivatives due to non-covalent dimeric interactions. The high conductance state observed in PPP is selectively enhanced or diminished in the presence of an oxidizing or reducing agent, respectively. The electronic properties of PPP are further characterized using cyclic voltammetry, electrolysis, and electron spin resonance, revealing that the high conductance state in PPP arises due to robust Au-C bond formation facilitated by a single electron oxidation event and stabilized by a rigid resonance structure under an electric field. Surface enhanced Raman spectroscopy (SERS) and X-ray photoelectron spectroscopy (XPS) are further used to confirm the robust formation of an Au-C bond. A series of control experiments with different anchor groups reveals the role of primary amines in forming dynamic linkages in molecular junctions. Overall, these results suggest that Au-C bond formation gives rise to high conductance pathways in organic molecules containing only one terminal anchor. Insights from this work can be leveraged in the design of molecular electronic devices, particularly in understanding the mechanisms of molecular binding and junction formation.

Incorporating 2,3-dihydrofuran (DHF) into dicyclopentadiene (DCPD) enables frontally polymerizable, deconstructible thermosets via acid hydrolysis. At 5-20 mol% DHF and low initiator concentration (similar to 100 ppm), DHF inhibits front propagation, lowers the glass transition temperature (T-g ) by up to 20 degrees C, and quenches the front, especially at 20% DHF. This paper demonstrates that increasing the initiator concentration to 250-1000 ppm overcomes inhibition, enhances front speeds by similar to 50%, and suppresses quenching at the expense of pot-life. Above 5 mol% DHF, an emergence of a second exotherm is observed, attributed to increased rate dependence on the inhibition of the initiator by DHF. Void formation from volatile DHF is suppressed by applying 110 kPa nitrogen, though at the cost of reduced front speed. Dynamic mechanical analysis shows that higher initiator concentration produced more highly cross-linked polymers, with a similar to 20% increase in storage modulus at 25 degrees C and a 20 degrees C increase in T-g.

Spontaneous chiral symmetry breaking remains a fascination in chemistry, biology, materials science, and even astronomy. Chiral symmetry breaking usually requires intrinsic molecular chirality or extrinsic chiral sources but remains rare in nonchiral systems. Here, we reveal a ubiquitous, entropy-driven chiral symmetry breaking mechanism observed in 22 out of 35 conjugated polymers in the absence of any chiral source─a phenomenon overlooked for decades. Chiral assemblies spontaneously occur through liquid-liquid phase separation (LLPS) of lyotropic mesophases from isotropic solutions upon a concentration increase. Machine learning identifies the underpinning molecular features validated by further molecular design. The universality of this phenomenon hints at a possible link between LLPS and chiral symmetry breaking in the origin of life, while paving the way for an emerging frontier of chiral electronics.

Frontal ring-opening metathesis polymerization (FROMP) offers an energy-efficient method for manufacturing high-performance thermoset resins. However, the background reaction attributed to ring-opening metathesis polymerization (ROMP) results in a complex trade-off between the resin shelf life─necessary for practical manufacturability─and the front velocity. Here, we study the influence of alkylidene ligand selection in Grubbs' second-generation Ru-initiators on the kinetics of FROMP and background ROMP. We reveal that ligand identity differentially affects FROMP and background ROMP reactivity, enabling tunable control over pot life and front speed. Leveraging this insight, we use active learning with multiobjective Bayesian optimization to efficiently explore the FROMP resin design space and identify superior resin formulations. This work advances the rational design of FROMP resins, expanding the range of accessible formulations and accelerating the discovery of high-performance materials for energy-efficient manufacturing applications.