ACS Materials Letters最新文献

The transition to a circular bioeconomy is driving the development of nature-inspired smart materials that improve performance and sustainability. This review highlights trends in smart bioinspired materials designed to meet future food demands while enhancing agricultural sustainability. It focuses on properties like wettability, antimicrobial activity, biocompatibility, biodegradability, and gas and water permeability, among others. The application of smart material coatings on conventional fertilizers, seeds, and fruits is discussed, along with the design of nanodelivery systems to enhance agrochemical efficiency and the effectiveness of plant growth-promoting rhizobacteria. Additionally, the review examines the use of bioinspired smart materials for transparent film packaging of fruits and vegetables, mulching, disease detection, and nutrient quantification, as well as hydrogels for atmospheric water harvesting. Overall, this review sets a strong standard for the design and fabrication of smart materials in agriculture, promoting a sustainable future from seed sowing to consumption.

Adhesive gels that combine high stretchability, conductivity, and biocompatibility are attractive for use in wearable electronics. However, integrating functional nanomaterials and reinforcing moieties coherently into deformable gels remains challenging. Here, we report a sponge-structured adhesive gel formed by embedding an interfacially engineered nanoscaffold within semi-interpenetrating polymer networks. The nanoscaffold, created by coating carbon nanotubes with polydopamine and silver nanoparticles, improves dispersion stability, promotes dynamic bonding with polymer chains, and triggers in-situ polymerization of a secondary nanoscale network. The spongelike structure enables stress redistribution, continuous electron transport, and robust cohesion under large and repeated deformation. The gel exhibits high stretchability (∼3600%), reliable conductivity, and 14 KPa adhesion on pig skin with good biocompatibility, allowing sensitive and stable strain recording from subtle finger motions to complex joint movements over 3 h. This work highlights interfacial molecular engineering as an effective strategy to couple molecular interactions with structural integration for multifunctional gels in wearable electronics.

Metal–organic frameworks (MOFs) combine structural flexibility with chemical tunability, offering an ideal platform for engineering extreme thermal expansion behavior. Herein, we report two nearly isostructural ytterbium tricarboxylates, Yb-BTC (BTC = 1,3,5-benzenetricarboxylate) and Yb-CTC (CTC = 1,3,5-cyclohexanetricarboxylate), that exhibit rare areal negative thermal expansion (NTE). Intriguingly, replacing the aromatic BTC ligand with its non-aromatic CTC analogue can simultaneously broaden and strengthen the NTE response. The Yb-CTC shows NTE over an ultrawide temperature range from 100 to 900 K, surpassing most inorganic ceramics and setting a benchmark for MOF-based NTE materials. Comprehensive experimental and theoretical investigations reveal that this enhancement arises from two cooperative effects: stronger Yb–O coordination significantly improves thermal stability, while the reduced carboxylate rotational barrier introduces abundant low-frequency phonons with negative Grüneisen parameters. These synergistic effects demonstrate a new strategy for regulating NTE in MOFs, enabling simultaneous control over both temperature range and contraction magnitude.

Ammonia (NH₃) is vital for modern agriculture and is a potential carbon-free energy carrier. However, its current synthesis via the Haber-Bosch process is energy-intensive, consuming ∼2% of global energy and emitting over 500 Mt of CO₂ annually. To address the growing demands for sustainable nitrogen fixation, alternative ammonia synthesis methods under ambient conditions have gained attention. Electrochemical (ENRR), photochemical (PNRR), and biocatalytic (BNRR) nitrogen reduction reactions (NRRs) offer promising approaches. ENRR uses renewable electricity but faces low Faradaic efficiency and competition from hydrogen evolution. PNRR utilizes solar energy but suffers from poor selectivity and low quantum yields. BNRR mimics nitrogenase enzymes with high selectivity but struggles with ATP dependency and scalability. Advances in catalyst design, single-atom engineering, and isotopic validation have improved these strategies, yet challenges remain. This review explores progress, mechanisms, and future directions for sustainable ammonia production.

Diamond, the hardest natural material, is scarce and expensive to mine, motivating efforts to synthesize high-performance diamond. Dislocations are key microstructural features governing diamond’s mechanical properties, yet their design mechanisms remain unclear. In this work, our large-scale molecular dynamics (MD) simulations demonstrate that the density of screw dislocation in cubic diamond (CD) increases with the increase of chiral angle differences between adjacent graphene layers in multiwalled carbon nanotubes (MWCNTs) during the CNT–diamond phase transition. During the phase transition, larger initial chiral angle differences between adjacent graphene layers increase the zigzag-chain orientation mismatch so that in regions with closely spaced chain intersections the CNT transforms into diamond, whereas in regions with larger mismatch the CNT evolves into screw dislocations. This study reveals the dominant role of the CNT chiral angle in controlling screw dislocations and offers a theoretical framework for improving the performance of synthetic diamond.

The removal of uranium(VI) from wastewater is crucial for environmental protection and the development of sustainable nuclear energy. Capacitive deionization (CDI) represents a promising electrochemical strategy, yet its deployment in uranium remediation has been hindered by the absence of efficient electrode materials. Herein, we report a redox-active polymer (PyHATP) electrode that introduces a novel coordination-driven electrochemical extraction concept for highly efficient uranium capture. The π-delocalized framework and abundant redox-active moieties synergistically enhance charge transport and promote reversible UO₂²⁺ coordination. In situ characterizations, density functional theory, and molecular dynamics simulations reveal a strong chelation between UO₂²⁺ and C═N bonds in the PyHATP lattice, underpinning its selectivity and performance. A proof-of-concept CDI device achieves a record UO₂²⁺ adsorption capacity of 676.4 mg g^–1, outstanding regeneration stability, and environmental compatibility. In real uranium-contaminated seawater, the system maintains >90% removal efficiency. These findings establish polymer-based CDI as an efficient, selective, and sustainable platform for radioactive wastewater remediation.

Metal–organic frameworks with a photoaccessible d-manifold are potentially useful for redox catalysis. Yet, electronic structure calculations of materials composed of Zr(IV) preclude the photogeneration of Zr(III). This finding contrasts with a handful of studies that invoke a Zr(III) center in proposed catalytic cycles. Defects may be responsible for stabilizing Zr(III) centers. Here we examine the effects of hydrogenic and oxygenic defects on the position of the band edges in a representative Zr(IV)-containing framework, UiO-66. While Brønsted acid/base-type defects are generally favorable, none yield a Zr d-state below the computational hydrogen evolution reaction (HER). However, oxygenic vacancies may stabilize a Zr d-orbital ∼0.5 eV below the HER. The oxygenic defect occurs with a formation energy of +2.3 eV, and concentration of 1.50 × 10^–7 defects/mol at 373 K of Zr(III), essentially preventing the defect without alternative stabilization. If such vacancies were installed, they may be the origin of Zr(III).

We compare the direct piezoelectric response of the room temperature ionic liquid (RTIL) N-butylpyridinium bis(trifluoromethyl-sulfonyl)imide (C₄Py TFSI) under conditions where pressure is applied to the bulk RTIL in a vessel with a bare ITO interface and a vessel with an ITO interface modified with a monolayer of a pyridinium-containing amphiphile. We find that the presence of a single monolayer of the pyridinium amphiphile poises the RTIL structurally to produce a measurably larger piezoelectric response. The extent of order imposed by the presence of the monolayer is likely limited by the intrinsic surface roughness and structural irregularity of the ITO-coated glass support used.

N-type organic electrochemical transistors (OECTs) hold promise for cation-responsive bioelectronics; however, their application in this area lags behind that of their p-type counterparts. Here, we introduce a BBL:PVB18C6 polymer blend synthesized via acid-mediated in situ polymerization of vinylbenzo-18-crown-6 (VB18C6) in the presence of poly(benzimidazobenzophenanthroline) (BBL) in methanesulfonic acid, enabling homogeneous integration of crown ether motifs selective for K⁺. Quantitative integration of the X-ray photoemission spectra provided direct evidence of differential cation uptake in BBL and BBL:PVB18C6, underscoring the cation recognition capability of the polymer blend. When employed as the channel in OECTs, BBL:PVB18C6 devices exhibit enhanced drain current, 76% higher volumetric capacitance in KCl (395 F cm^–3) compared to NaCl (225 F cm^–3), and concentration-dependent response toward K⁺ over Na⁺, while retaining excellent operational stability. This work establishes a strategy for functionalizing BBL with ion-selective motifs, enabling the development of cation-dependent n-type OECTs.

While postsynthetic modification (PSM) of metal–organic frameworks (MOFs) through solvent assisted ligand incorporation (SALI) has been extensively studied, particularly in Zr₆-based MOFs, this PSM approach is largely overlooked in the literature on rare-earth (RE) cluster-based MOFs. In this work, we explore SALI in Y-CU-45 (CU = Concordia University), a Y₆-MOF analogous to Zr-MOF-808 with a 6-connected Y₆-node. The structural connectivity of Y-CU-45 allows for the existence of six coordinatively unsaturated sites per cluster. We previously demonstrated that these sites are capped by modulators used in the synthesis of Y-CU-45, which partially occlude the pores of the MOF. By performing SALI on Y-CU-45 with seven different ligands: formate, acetate, trifluoroacetate, pivalate, benzoate, 2,3,4,5-tetrafluorobenzoate, and 2,6-bis(trifluoromethyl)benzoate, we demonstrate that the pores and open metal sites of Y-CU-45 can be made more accessible.