Next-generation structural materials are expected to be lightweight, high strength, and tough composites with embedded functionalities to sense, adapt, self-repair, morph, and restore. This review highlights recent developments and concepts in bioinspired nanocomposites, emphasizing tailoring the architecture, interphases, and confinement to achieve dynamic and synergetic responses. We highlight cornerstone examples from natural materials with unique mechanical property combinations based on relatively simple building blocks produced in aqueous environments at ambient conditions. A particular focus is on structural hierarchies across multiple length scales to achieve multifunctionality and robustness. We further discuss recent advances, trends, and emerging opportunities in combining biological and synthetic components, state-ofthe-art characterization, and modelling approaches to assess the physical principles underlying nature design and mechanical responses at multiple length scales. These multidisciplinary approaches promote the synergetic enhancement of individual materials properties and an improved predictive and prescriptive design of the next era of structural materials at multi-length scales for a wide range of applications.

Inverse vulcanization provides dynamic and responsive materials made from elemental sulfur and unsaturated cross-linkers. These polymers have been used in av ariety of applicationss uch as energy storage, infrared optics, repairable materials, environmental remediation, and precision fertilizers. In spite of thesea dvances, there is an eed for methods to recycle and reprocess these polymers. In this study,p olymers prepared by inverse vulcanization are shown to undergo reactive compression molding. In this process, the reactive interfaces of sulfur polymers are brought into contact by mechanicalc ompression.U pon heating these molds at relatively low temperatures (% 100 8C), chemical bonding occurs at the polymer interfaces by SÀSm etathesis. This method of processing is distinct from previouss tudies on inverse vulcanization because the polymers examined in this study do not form al iquid phase when heated. Neither compression nor heatinga lone was sufficient to mold these polymers into new architectures, so this is an ew concept in the manipulation of sulfur polymers. Additionally,h igh-level ab initio calculations revealed that the weakest SÀSb ond in organic polysulfides decreases linearly in strength from as ulfur rank of 2t o4 ,b ut then remains constant at about 100kJmol À1 for highers ulfur rank. This is criticali nformation in engineering these polymers for SÀSm etathesis. Guidedb yt his insight, polymer repair,r ecycling, and repurposingi nto new composites was demonstrated.

A new strategy to create iridium(iii)-based ECL labels reveals limitations of conventional approaches.

Carbon-fiber reinforced composites are ideal light-weighting candidates to replace traditional engineering materials. The mechanical performance of these composites results from a complex interplay of influences operating over several length and time scales. The mechanical performance may therefore be limited by many factors, one of which being the modest interfacial adhesion between the carbon fiber and the polymer. Chemical modification of the fiber, via surface grafting of molecules, is one possible strategy to enhance interactions across the fiber-polymer interface. To achieve systematic improvements in these modified materials, the ability to manipulate and monitor the molecular structure of the polymer interphase and the surface grafted molecules in the composite is essential, but challenging to accomplish from a purely experimental perspective. Alternatively, molecular simulations can bridge this knowledge gap by providing molecular-scale insights into the optimal design of these surface-grafted molecules to deliver superior mechanical properties. Here we use molecular dynamics simulations to predict the interfacial shear response of a typical epoxy/carbon-fiber composite for both pristine fiber and a range of surface graftings. We allow for the dynamic curing of the epoxy in the presence of the functionalized surface, including cross-link formation between the grafted molecules and the polymer matrix. Our predictions agree with recently reported experimental data for these systems and reveal the molecular-scale origins of the enhanced interfacial shear response arising from functionalization. In addition to the presence of interfacial covalent bonds, we find that the interfacial structural complexity, resulting from the presence of the grafted molecules, and a concomitant spatial homogeneity of the interphase polymer density are beneficial factors in conferring high interfacial shear stress. Our approach paves the way for computational screening processes to design, test, and rapidly identify viable surface modifications in silico, which would enable rapid systematic progress in optimizing the match between the carbon fiber treatment and the desired thermoset polymer matrix.