Chemistry of Materials : a Publication of the American Chemical Society

Reversible addition-fragmentation chain transfer (RAFT) aqueous emulsion polymerization is used to prepare well-defined ABCB tetrablock copolymer nanoparticles via sequential monomer addition at 30 °C. The A block comprises water-soluble poly(2-( N -acryloyloxy)ethyl pyrrolidone) (PNAEP), while the B and C blocks comprise poly( t -butyl acrylate) (PtBA) and poly( n -butyl acrylate) (PnBA), respectively. High conversions are achieved at each stage, and the final sterically stabilized spherical nanoparticles can be obtained at 20% w/w solids at pH 3 and at up to 40% w/w solids at pH 7...

Rare-earth (RE) metal-organic frameworks (MOFs) synthesized in the presence of fluorine-donating modulators or linkers are an important new subset of functional MOFs. However, the exact nature of the RE a X b core of the molecular building block (MBB) of the MOF, where X is a μ2 or 3 -bridging group, remains unclear. Investigation of one of the archetypal members of this family with the stable fcu framework topology, Y-fum- fcu -MOF ( 1 ), using a combination of experimental techniques, including high-field (20 T) solid-state nuclear magnetic resonance spectroscopy, has determined two sources of framework disorder involving the μ3 -X face-capping group of the MBB and the fumarate (fum) linker...

We report superconductivity in the full Heusler compound LiPd2 Si (space group Fm3̅m , No. 225) at a critical temperature of T c = 1.3 K and a normalized heat capacity jump at T c , Δ C /γ T c = 1.1. The low-temperature isothermal magnetization curves imply type-I superconductivity, as previously observed in LiPd2 Ge. We show, based on density functional theory calculations and using the molecular orbital theory approach, that while LiPd2 Si and LiPd2 Ge share the Pd cubic cage motif that is found in most of the reported Heusler superconductors, they show distinctive features in the electronic structure...

Organic electrochemical transistors (OECTs) are signal transducers offering high amplification, which makes them particularly advantageous for detecting weak biological signals. While OECTs typically operate with aqueous electrolytes, those employing solid-like gels as the dielectric layer can be excellent candidates for constructing wearable electrophysiology probes. Despite their potential, the impact of the gel electrolyte type and composition on the operation of the OECT and the associated device design considerations for optimal performance with a chosen electrolyte have remained ambiguous...

This work discusses the use of donor and acceptor materials from organic photovoltaics in solar fuel applications. These two routes to solar energy conversion have many shared materials design parameters, and in recent years there has been increasing overlap of the molecules and polymers used in each. Here, we examine whether this is a good approach, where knowledge can be translated, and where further consideration to molecular design is required.

Photoacids are organic molecules that release protons under illumination, providing spatiotemporal control of the pH. Such light-driven pH switches offer the ability to cyclically alter the pH of the medium and are highly attractive for a wide variety of applications, including CO2 capture. Although photoacids such as protonated merocyanine can enable fully reversible pH cycling in water, they have a limited chemical stability against hydrolysis (<24 h). Moreover, these photoacids have low solubility, which limits the pH-switching ability in a buffered solution such as dissolved CO2 ...

By variation of the chemical repeat units of conjugated polymers, only discrete tuning of essential physical parameters is possible. A unique property of a class of π-conjugated polymers, where polycyclic aromatic hydrocarbons are linked via ethynylene linkers, is their topological aromatic to quinoid phase transition discovered recently by Cirera et al. and González-Herrero et al., which is controllable in discrete steps by chemical variations. We have discovered by means of density functional theory computations that such a phase transition can be achieved by applying continuous variations of longitudinal strain, allowing us to tune the bond length alternation and bandgap...

Several synthetic methods have recently emerged to develop high-surface-area solid-state organic framework-based materials into free-flowing liquids with permanent porosity. The fluidity of these porous liquid (PL) materials provides them with advantages in certain storage and transport processes. However, most framework-based materials necessitate the use of cryogenic temperatures to store weakly bound gases such as H2 , temperatures where PLs lose their fluidity. Covalent organic framework (COF)-based PLs that could reversibly form stable complexes with H2 near ambient temperatures would represent a promising development for gas storage and transport applications...

Theoretical studies have identified cesium titanium bromide (Cs2 TiBr6 ), a vacancy-ordered double perovskite, as a promising lead-free and earth-abundant candidate to replace Pb-based perovskites in photovoltaics. Our research is focused on overcoming the limitations associated with the current Cs2 TiBr6 syntheses, which often involve high-vacuum and high-temperature evaporation techniques, high-energy milling, or intricate multistep solution processes conducted under an inert atmosphere, constraints that hinder industrial scalability...

[This corrects the article DOI: 10.1021/acs.chemmater.3c01603.].

Organic active materials are seen as next-generation battery materials that could circumvent the sustainability and cost limitations connected with the current Li-ion battery technology while at the same time enabling novel battery functionalities like a bioderived feedstock, biodegradability, and mechanical flexibility. Many promising research results have recently been published. However, the reproducibility and comparison of the literature results are somehow limited due to highly variable electrode formulations and electrochemical testing conditions...

Reactive oxygen species (ROS) play a key role in several biological functions like regulating cell survival and signaling; however, their effect can range from beneficial to nondesirable oxidative stress when they are overproduced causing inflammation or cancer diseases. Thus, the design of tailor-made ROS-responsive polymers offers the possibility of engineering hydrogels for target therapies. In this work, we developed thioether-based ROS-responsive difunctional monomers from ethylene glycol/thioether acrylate (EG n SA) with different lengths of the EG n chain ( n = 1, 2, 3) by the thiol-Michael addition click reaction...

Molecular layer deposition (MLD) provides the opportunity to perform condensation polymerization one vaporized monomer at a time for the creation of precise, selective nanofilms for desalination membranes. Here, we compare the structure, chemistry, and morphology of two types of commercial interfacial polymerzation (IP) membranes with lab-made MLD films. M-phenylenediamine (MPD) and trimesoyl chloride (TMC) produced a cross-linked, aromatic polyamide often used in reverse osmosis membranes at MLD growth rates of 2...

In situ synchrotron powder X-ray diffraction (PXRD) study was conducted on sodium and potassium tetrafluoroborate (NaBF4 and KBF4 ) to elucidate structural changes across solid-solid phase transitions over multiple heating-cooling cycles. The phase transition temperatures from diffraction measurements are consistent with the differential scanning calorimetry data (∼240 °C for NaBF4 and ∼290 °C for KBF4 ). The crystal structure of the high-temperature (HT) NaBF4 phase was determined from synchrotron PXRD data...

Lithium ortho-thiophosphate (Li3 PS4 ) has emerged as a promising candidate for solid-state electrolyte batteries, thanks to its highly conductive phases, cheap components, and large electrochemical stability range. Nonetheless, the microscopic mechanisms of Li-ion transport in Li3 PS4 are far from being fully understood, the role of PS4 dynamics in charge transport still being controversial. In this work, we build machine learning potentials targeting state-of-the-art DFT references (PBEsol, r2 SCAN, and PBE0) to tackle this problem in all known phases of Li3 PS4 (α, β, and γ), for large system sizes and time scales...

Persistent neutral organic radicals are excellent building blocks for the design of functional molecular materials due to their unique electronic, magnetic, and optical properties. Among them, triphenylmethyl radical derivatives have attracted a lot of interest as luminescent doublet emitters. Although neutral organic radicals have been underexplored as linkers for building metal-organic frameworks (MOFs), they hold great potential as organic elements that could introduce additional electronic properties within these frameworks...

We used data-driven methods to understand the formation of impurity phases in BiFeO3 thin-film synthesis through the sol-gel technique. Using a high-quality dataset of 331 synthesis procedures and outcomes extracted manually from 177 scientific articles, we trained decision tree models that reinforce important experimental heuristics for the avoidance of phase impurities but ultimately show limited predictive capability. We find that several important synthesis features, identified by our model, are often not reported in the literature...

To improve the energy density of LiFePO4 (LFP) cathode materials for Li-ion cells, we have utilized a modified mechanofusion method for preparing micrometer-sized LFP/C composite flake particles. The resulting flake particle morphology resulted in improved packing efficiency, enabling an electrode porosity of 14% to be achieved at high loadings, which represents a volumetric energy density increase of 28% compared to conventional LFP. Furthermore, LFP/C flake composites electrodes were found to have a higher coulombic efficiency, a reduced voltage-polarization, and a greatly reduced charge transfer resistance compared to conventional LFP electrodes...

This study examines the chemical reaction pathways for vapor phase infiltration (VPI) of TiCl4 into poly(methyl methacrylate) (PMMA). VPI is a processing method that transforms organic polymers into organic-inorganic hybrid materials with new properties of interest for microelectronic patterning, technical textiles, and chemical separations. Understanding the fundamental chemical mechanisms of the VPI process is essential for establishing approaches to design the chemical structure and properties of these hybrid materials...

Helicoidal crystallites in rhythmically banded spherulites manifest spectacular optical patterns in small molecules and polymers. It is shown that concentric optical bands indicating crystallographic orientations typically lose coherence (in-phase twisting) with growth from the center of nucleation. Here, coherence is shown to increase as the twist period decreases for seven molecular crystals grown from the melt. This dependence was correlated to crystallite fiber thickness and length, as well as crystallite branching frequency, a parameter that was extracted from scanning electron micrographs, and supported by numerical simulations...