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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 721 records · Page 40

A {Ni 12 }-Wheel-Based Metal-Organic Framework for Coordinative Binding of Sulphur Dioxide and Nitrogen Dioxide

Air pollution by SO 2 and NO 2 has caused significant risks on the environment and human health. Understanding the mechanism of active sites within capture materials is of fundamental importance to the development of new clean-up technologies. We report the crystallographic observation of reversible coordinative binding of SO 2 and NO 2 on open Ni II sites in a metal-organic framework (NKU-100) incorporating unprecedented {Ni 12 }-wheels; each wheel exhibits six open Ni II sites on desolvation. Immobilised gas molecules are further stabilised by cooperative host-guest interactions comprised of hydrogen bonds, π∙∙∙π interactions and dipole interactions. At 298 K and 1.0 bar, NKU-100 shows adsorption uptakes of 6.21 and 5.80 mmol g -1 for SO 2 and NO 2 , respectively. Dynamic breakthrough experiments have confirmed the selective retention of SO 2 and NO 2 at low concentrations under dry conditions. This work will inspire the future design of efficient sorbents for the capture of SO 2 and NO 2 .

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Peptoid-Directed Formation of Five-Fold Twinned Au Nanostars through Particle Attachment and Facet Stabilization

While bio-inspired synthesis offers great potential for controlling nucleation and growth of inorganic particles, precisely tuning biomolecule-particle interactions is a long-standing challenge. Herein, we used variations in peptoid sequence to manipulate peptoid-Au interaction, leading to synthesis of concave five-fold twinned, five-pointed Au nanostars via a process of repeated particle attachment and facet stabilization. Ex situ and liquid-phase TEM observations show that a balance between particle attachment biased to occur near the star points, preferential growth along the [100] direction, and stabilization of (111) facets is critical to forming star-shaped particles. Molecular simulations predict that interaction strengths between peptoids and distinct Au facets differ significantly and thus can alter attachment kinetics and surface energies to form the stars. This work provides new insights into how sequence-defined ligands affect particle growth to regulate crystal morphology.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Salt‐in‐Salt Reinforced Carbonate Electrolyte for Li Metal Batteries

Abstract The instability of carbonate electrolyte with metallic Li greatly limits its application in high‐voltage Li metal batteries. Here, a “salt‐in‐salt” strategy is applied to boost the LiNO 3 solubility in the carbonate electrolyte with Mg(TFSI) 2 carrier, which enables the inorganic‐rich solid electrolyte interphase (SEI) for excellent Li metal anode performance and also maintains the cathode stability. In the designed electrolyte, both NO 3 − and PF 6 − anions participate in the Li + ‐solvent complexes, thus promoting the formation of inorganic‐rich SEI. Our designed electrolyte has achieved a superior Li CE of 99.7 %, enabling the high‐loading NCM811||Li (4.5 mAh cm −2 ) full cell with N/P ratio of 1.92 to achieve 84.6 % capacity retention after 200 cycles. The enhancement of LiNO 3 solubility by divalent salts is universal, which will also inspire the electrolyte design for other metal batteries.

25 ENERGY STORAGE↗

Two–Dimensional Excitonic Networks Directed by DNA Templates as an Efficient Model Light–Harvesting and Energy Transfer System

Photosynthetic organisms organize discrete light-harvesting complexes into large-scale networks to facilitate efficient light collection and utilization. Inspired by nature, herein, synthetic DNA templates were used to direct the formation of dye aggregates with a cyanine dye, K21, into discrete branched photonic complexes, and two-dimensional (2D) excitonic networks. The DNA templates ranged from four-arm DNA tiles, ≈10 nm in each arm, to 2D wireframe DNA origami nanostructures with different geometries and varying dimensions up to 100×100 nm. These DNA-templated dye aggregates presented strongly coupled spectral features and delocalized exciton characteristics, enabling efficient photon collection and energy transfer. Compared to the discrete branched photonic systems templated on individual DNA tiles, the interconnected excitonic networks showed approximately a 2-fold increase in energy transfer efficiency. Lastly, this bottom-up assembly strategy paves the way to create 2D excitonic systems with complex geometries and engineered energy pathways.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Modelling Development in Radical (Co)Polymerization of Multivinyl Monomers

Radical polymerization (RP) of multivinyl monomers (MVMs) provides a facile solution for manipulating polymer topology and has received increasing attention due to their industrial and academic significance. Continuous efforts have been made to understand their mechanism, which is the key to regulating materials structure. Modelling techniques have become a powerful tool that can provide detailed information on polymerization kinetics which is inaccessible by experiments. Many publications have reported the combination of experiments and modelling for free radical polymerization (FRP) and reversible-deactivation radical polymerizations (RDRP) of MVMs. Herein, a minireview is presented for the most important modelling techniques and their applications in FRP/RDRP of MVMs. This review hopes to illustrate that the combination of modelling and wet experiments can be a great asset to polymer researchers and inspire new thinking for the future MVMs experiment optimization and product design.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Stabilizing Liquids Using Interfacial Supramolecular Assemblies

Stabilizing liquids based on supramolecular assembly (non-covalent intermolecular interactions) has attracted significant interest, due to the increasing demand for soft, liquid-based devices where the shape of the liquid is far from the equilibrium spherical shape. The components comprising these interfacial assemblies must have sufficient binding energies to the interface to prevent their ejection from the interface when the assemblies are compressed. In this report we highlight recent advances in structuring liquids based on non-covalent intermolecular interactions. We describe some of the progress made that reveals structure–property relationships. In addition to treating advances, we discuss some of the limitations and provide a perspective on future directions to inspire further studies on structured liquids based on supramolecular assembly.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Unidirectional Sidechain Engineering to Construct Dual‐Asymmetric Acceptors for 19.23 % Efficiency Organic Solar Cells with Low Energy Loss and Efficient Charge Transfer

Abstract Achieving both high open‐circuit voltage ( V oc ) and short‐circuit current density ( J sc ) to boost power‐conversion efficiency (PCE) is a major challenge for organic solar cells (OSCs), wherein high energy loss ( E loss ) and inefficient charge transfer usually take place. Here, three new Y‐series acceptors of mono‐asymmetric asy‐YC11 and dual‐asymmetric bi‐asy‐YC9 and bi‐asy‐YC12 are developed. They share the same asymmetric D 1 AD 2 (D 1 =thieno[3,2‐ b ]thiophene and D 2 =selenopheno[3,2‐ b ]thiophene) fused‐core but have different unidirectional sidechain on D 1 side, allowing fine‐tuned molecular properties, such as intermolecular interaction, packing pattern, and crystallinity. Among the binary blends, the PM6 : bi‐asy‐YC12 one has better morphology with appropriate phase separation and higher order packing than the PM6 : asy‐YC9 and PM6 : bi‐asy‐YC11 ones. Therefore, the PM6 : bi‐asy‐YC12‐based OSCs offer a higher PCE of 17.16 % with both high V oc and J sc , due to the reduced E loss and efficient charge transfer properties. Inspired by the high V oc and strong NIR‐absorption, bi‐asy‐YC12 is introduced into efficient binary PM6 : L8‐BO to construct ternary OSCs. Thanks to the broadened absorption, optimized morphology, and furtherly minimized E loss , the PM6 : L8‐BO : bi‐asy‐YC12‐based OSCs achieve a champion PCE of 19.23 %, which is one of the highest efficiencies among these annealing‐free devices. Our developed unidirectional sidechain engineering for constructing bi‐asymmetric Y‐series acceptors provides an approach to boost PCE of OSCs.

Chemistry↗

Mechanisms of Biomolecular Self–Assembly Investigated Through In Situ Observations of Structures and Dynamics

Biomolecular self-assembly of hierarchical materials is a precise and adaptable bottom-up approach to synthesizing across scales with considerable energy, health, environment, sustainability, and information technology applications. To achieve desired functions in biomaterials, it is essential to directly observe assembly dynamics and structural evolutions that reflect the underlying energy landscape and the assembly mechanism. This review will summarize the current understanding of biomolecular assembly mechanisms based on in situ characterization and discuss the broader significance and achievements of newly gained insights. In addition, we will also introduce how emerging deep learning/machine learning-based approaches, multiparametric characterization, and high-throughput methods can boost the development of biomolecular self-assembly. Furthermore, the objective of this review is to accelerate the development of in situ characterization approaches for biomolecular self-assembly and to inspire the next generation of biomimetic materials.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Spatiotemporal Studies of Soluble Inorganic Nanostructures with X‐rays and Neutrons

This Review addresses the use of X-ray and neutron scattering as well as X-ray absorption to describe how inorganic nanostructured materials assemble, evolve, and function in solution. We first provide an overview of techniques and instrumentation (both large user facilities and benchtop). We review recent studies of soluble inorganic nanostructure assembly, covering the disciplines of materials synthesis, processes in nature, nuclear materials, and the widely applicable fundamental processes of hydrophobic interactions and ion pairing. Reviewed studies cover size regimes and length scales ranging from sub-Ångström (coordination chemistry and ion pairing) to several nanometers (molecular clusters, i.e. polyoxometalates, polyoxocations, and metal-organic polyhedra), to the mesoscale (supramolecular assembly processes). Reviewed studies predominantly exploit 1) SAXS/WAXS/SANS (small- and wide-angle X-ray or neutron scattering), 2) PDF (pair-distribution function analysis of X-ray total scattering), and 3) XANES and EXAFS (X-ray absorption near-edge structure and extended X-ray absorption fine structure, respectively). While the scattering techniques provide structural information, X-ray absorption yields the oxidation state in addition to the local coordination. Our goal for this Review is to provide information and inspiration for the inorganic/materials science communities that may benefit from elucidating the role of solution speciation in natural and synthetic processes.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Transient Covalent Polymers through Carbodiimide‐Driven Assembly

Biochemical systems make use of out-of-equilibrium polymers generated under kinetic control. Inspired by these systems, many abiotic supramolecular polymers driven by chemical fuel reactions have been reported. Conversely, polymers based on transient covalent bonds have received little attention, even though they have the potential to complement supramolecular systems by generating transient structures based on stronger bonds and by offering a straightforward tuning of reaction kinetics. In this study, we show that simple aqueous dicarboxylic acids give poly(anhydrides) when treated with the carbodiimide EDC. Transient covalent polymers with molecular weights exceeding 15,000 are generated which then decompose over the course of hours to weeks. Disassembly kinetics can be controlled using simple substituent effects in the monomer design. The impact of solvent polarity, carbodiimide concentration, temperature, pyridine concentration, and monomer concentration on polymer properties and lifetimes has been investigated. The results reveal substantial control over polymer assembly and disassembly kinetics, highlighting the potential for fine-tuned kinetic control in nonequilibrium polymerization systems.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Nikki A. Thiele

“The best advice I have ever been given is: ‘The faster you go, the behinder you get.’ This was a favorite phrase of my graduate school advisor, and one that I say often to myself, even years later… My biggest inspiration is my father, Wayne Thiele, who taught me how to work hard and never give up…” Here, find out more about Nikki Thiele in her Introducing… Profile.

99 GENERAL AND MISCELLANEOUS↗

Boosting Hydrogenation of CO 2 Using Cationic Cu Atomically Dispersed on 2D γ‐Al 2 O 3 Nanosheets

The continuous development of novel catalytic approaches is crucial for advancing efficient CO 2 hydrogenation processes. Drawing inspiration from single-atom catalysis and 2D materials, we designed a new 2D single-atom catalyst with excellent thermal stability by thermally treating Cu-adsorbed γ-AlOOH nanosheets, which yielded a Cu/γ-Al 2 O 3 catalyst with high activity in the hydrogenation of CO 2 -yielding methanol (CH 3 OH), dimethyl ether (DME), and CO as products. The active Cu sites are monodispersed and highly stable due to their cationic oxidation state and their substitution for pentacoordinated aluminum (Al P ) sites on particle surfaces. This study demonstrates an efficient approach for achieving a high CO 2 hydrogenation rate (30.45 mol mol −1 h −1 ) using a catalyst system that lacks metallic Cu centers, traditionally considered essential for H₂ dissociation, and employs what was previously thought to be an inert metal oxide (γ-Al 2 O 3 ) for CO and CH 3 OH production. Ongoing mechanistic studies aim to elucidate the synergy between cationic Cu single atoms and γ-Al 2 O 3 , a Lewis acid support, in facilitating hydrogen (H 2 ) activation and methanol formation.

2D catalyst↗

Blocky Selective Postpolymerization C–H Functionalization of Polyolefins

C–H functionalization of commodity polyolefins affords functional materials derived from a high-volume, low-cost resource. However, current postpolymerization modification strategies result in randomly distributed functionalization along the length of the polymer backbone, which has a negative impact on the crystallinity of the resultant polymers, and thus the thermomechanical properties. Here, we demonstrate an amidyl radical mediated C–H functionalization of polyolefins to access blocky microstructures, which exhibit a higher crystalline fraction, larger crystallite size, and improved mechanical properties compared to their randomly functionalized analogues. Taking inspiration from the site-selective C–H functionalization of small molecules, we leverage the steric protection provided by crystallites and target polymer functionalization to amorphous domains in a semicrystalline polyolefin gel. The beneficial outcomes of blocky functionalization are independent of the identity of the pendant functional group that is installed through functionalization. Here, the decoupling of functional group incorporation and crystallinity highlights the promise in accessing nonrandom microstructures through selective functionalization to circumvent traditional tradeoffs in postpolymerization modification, with potential impact in advanced materials and upcycling plastic waste.

Neidhart, Eliza K. [The University of North Caroli↗

Polysulfamates as “Macroisosteres” of Polyurethanes with Improved Degradability

Abstract Addressing the environmental persistence of plastics requires the development of next‐generation polymers that combine high performance with enhanced degradability. Progress toward this grand challenge has been impeded, in part, by the absence of a general blueprint for the macromolecular design of such materials. Herein, we introduce a “macroisostere” design strategy, where the carbonyl group (–CO–) in polyurethanes (PUs) is replaced with a sulfonyl group (–SO 2 –), resulting in a virtually unknown family of polymers called polysulfamates. This approach, inspired by the use of bioisosteres in drug discovery, aims to preserve key interchain interactions that contribute to thermomechanical performance while enhancing the hydrolytic lability of the polymer backbone. The optimization of a Sulfur(VI) Fluoride Exchange (SuFEx) polymerization allowed the synthesis of ten polysulfamates structurally analogous to common PUs. Comparative analysis of one PU and its polysulfamate analog showed that this isosteric substitution increases thermal stability, slightly lowers the glass transition temperature, and retains similar hardness and reduced Young's modulus. Notably, the S(VI)‐based polysulfamate demonstrated significantly enhanced hydrolytic degradability. These results highlight the potential of the “macroisostere” approach as a generalizable strategy for designing high‐performance, degradable alternatives to traditional plastics.

Chemistry↗

Self‐assembling Peptides with Internal Ionizable Unnatural Amino Acids: A General Approach to pH‐responsive Peptide Materials

Self‐assembled peptides are an emerging family of biomaterials that show great promise for a range of biomedical and biotechnological applications. Introducing and tuning the pH‐responsiveness of the assembly is highly desirable for improving their biological activities. Inspired by proteins with internal ionizable residues, we report a simple but effective approach to constructing pH‐responsive peptide assembly containing unnatural ionic amino acids with an aliphatic tertiary amine side chain. Through a combined experimental and computational investigation, we demonstrate that these residues can be accommodated and stabilized within the internal hydrophobic compartment of the peptide assembly. The hydrophobic microenvironment shifts their pK a significantly from a basic pH typically found for free amines to a more biologically relevant pH in the weakly acidic range. The pH‐induced ionization and ionization‐dependent self‐assembly and disassembly are thoroughly investigated and correlated with the biological activity of the assembly. This new approach has unique advantages in tuning the pH‐responsiveness of self‐assembled peptides across a large pH range in a complex biological environment. We anticipate the ionizable amino acids developed here can be widely applicable to the synthesis and self‐assembly of many amphiphilic peptides with endowed pH‐responsive properties to enhance their biological activities toward applications ranging from targeted therapeutic delivery to proton transport.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Light‐driven catalysis with engineered enzymes and biomimetic systems

Abstract Efforts to drive catalytic reactions with light, inspired by natural processes like photosynthesis, have a long history and have seen significant recent growth. Successfully engineering systems using biomolecular and bioinspired catalysts to carry out light‐driven chemical reactions capitalizes on advantages offered from the fields of biocatalysis and photocatalysis. In particular, driving reactions under mild conditions and in water, in which enzymes are operative, using sunlight as a renewable energy source yield environmentally friendly systems. Furthermore, using enzymes and bioinspired systems can take advantage of the high efficiency and specificity of biocatalysts. There are many challenges to overcome to fully capitalize on the potential of light‐driven biocatalysis. In this mini‐review, we discuss examples of enzymes and engineered biomolecular catalysts that are activated via electron transfer from a photosensitizer in a photocatalytic system. We place an emphasis on selected forefront chemical reactions of high interest, including CH oxidation, proton reduction, water oxidation, CO 2 reduction, and N 2 reduction.

Edwards, Emily H.↗

Roles of mineral matter in biomass processing to biofuels

Abstract Minerals in biomass have a significant impact on both biofuel quality and yield. This is especially true for current thermochemical biomass conversion processes. However, the roles of plant minerals in biochemical conversion have not been studied extensively, even though they are generally considered to lower the sugar yield because they reduce the feedstock proportion of carbohydrates. A successful strategic solution is thus necessary to overcome the challenges caused by the minerals in biomass, which include (1) decreased quality of biomass feedstocks; (2) reduction of process efficiency; and (3) reduction of the product quality and quantity from biomass conversion. This review summarizes the roles of plant minerals in a biorefinery, focusing on these key challenges. The discussion covers many issues related to plant minerals in biofuel production, including their sources, functions, and distribution in plant biomass, methods of characterizing them, their influence in a biorefinery, and the strategic handling required to manage their occurrence in biomass, based on reported studies. It could inspire better strategies to deal with the variance of mineral content in biomass feedstocks to increase process efficiency and reduce costs while supporting the concept of a circular bioeconomy. © 2023 The Authors. Biofuels, Bioproducts and Biorefining published by Society of Industrial Chemistry and John Wiley & Sons Ltd.

09 BIOMASS FUELS↗