Silver nanowires for flexible organic electronics have been comprehensively summarized from synthesis, film fabrication, characterization and applications to perspectives.

Cellulose nanocrystals (CNCs) exhibit impressive interfacial and mechanical properties that make them promising candidates to be used as fillers within nanocomposites. While glass-transition temperature (Tg) is a common metric for describing thermomechanical properties, its prediction is extremely difficult as it depends on filler surface chemistry, volume fraction, and size. Here, taking CNC-reinforced poly(methyl-methacrylate) (PMMA) nanocomposites as a relevant model system, we present a multiscale analysis that combines atomistic molecular dynamics (MD) surface energy calculations with coarse-grained (CG) simulations of relaxation dynamics near filler-polymer interfaces to predict composite properties. We discover that increasing the volume fraction of CNCs results in nanoconfinement effects that lead to an appreciation of the composite Tg provided that strong interfacial interactions are achieved, as in the case of TEMPO-mediated surface modifications that promote hydrogen bonding. The upper and lower bounds of shifts in Tg are predicted by fully accounting for nanoconfinement and interfacial properties, providing new insight into tuning these aspects in nanocomposite design. Our multiscale, materials-by-design framework is validated by recent experiments and breaks new ground in predicting, without any empirical parameters, key structure-property relationships for nanocomposites.

Most attempts to emulate the mechanical properties of strong and tough natural composites using helicoidal films of wood-derived cellulose nanocrystals (w-CNCs) fall short in mechanical performance due to the limited shear transfer ability between the w-CNCs. This shortcoming is ascribed to the small w-CNC-w-CNC overlap lengths that lower the shear transfer efficiency. Herein, we present a simple strategy to fabricate superior helicoidal CNC films with mechanical properties that rival those of the best natural materials and are some of the best reported for photonic CNC materials thus far. Assembling the short w-CNCs with a minority fraction of high aspect ratio CNCs derived from tunicates (t-CNCs), we report remarkable simultaneous enhancement of all in-plane mechanical properties and out-of-plane flexibility. The important role of t-CNCs is revealed by coarse grained molecular dynamics simulations where the property enhancement are due to increased interaction lengths and the activation of additional toughening mechanisms. At t-CNC contents greater than 5% by mass the mixed films also display UV reflecting behaviour. These damage tolerant optically active materials hold great promise for application as protective coatings. More broadly, we expect the strategy of using length-bidispersity to be adaptable to mechanically enhancing other matrix-free nanoparticle ensembles.

The proton/electron transfer reactions between cysteine residue (Cys) and tyrosinyl radical (Tyr(•)) are an important step for many enzyme-catalyzed processes. On the basis of the statistical analysis of protein data bank, we designed three representative models to explore the possible proton/electron transfer mechanisms from Cys to Tyr(•) in proteins. Our ab initio calculations on simplified models and quantum mechanical/molecular mechanical (QM/MM) calculations on real protein environment reveal that the direct electron transfer between Cys and Tyr(•) is difficult to occur, but an inserted water molecule can greatly promote the proton/electron transfer reactions by a double-proton-coupled electron transfer (dPCET) mechanism. The inserted H2O plays two assistant roles in these reactions. The first one is to bridge the side chains of Tyr(•) and Cys via two hydrogen bonds, which act as the proton pathway, and the other one is to enhance the electron overlap between the lone-pair orbital of sulfur atom and the π-orbital of phenol moiety and to function as electron transfer pathway. This water-mediated dPCET mechanism may offer great help to understand the detailed electron transfer processes between Tyr and Cys residues in proteins, such as the electron transfer from Cys439 to Tyr730(•) in the class I ribonucleotide reductase.

Due to their distinctive two-dimensional (2D) structure and excellent properties, MXenes have got much attention and developed very fast since their discovery in 2011. Generally, 2D MXenes are prepared by...