Latest ArticlesCovalent adaptable networks (CANs), which share the properties of both thermosets and thermoplastics at the same time, are desirable for many applications. Introducing bulky substituents is a feasible way to design dynamic covalent bonds for constructing CANs, as evidenced by the successful implementation in CANs based on hindered urea bonds (HUBs). However, the dynamicity induced by introducing bulky substituents always come with low bond energy, resulting in low mechanical strength and poor stability of the CANs. Herein, we designed a novel hindered urethane bond, which is weak in thermodynamic (Keq = 1701.23 L/mol at 25 ℃) and inert in kinetic at low temperature, but stable in thermodynamic (Keq = 1.54 × 104 L/mol at 100 ℃) and active in kinetic at high temperature (k-1 = 0.105 h−1 at 80 ℃ and 0.315 h−1 at 120 ℃). As a result, the polyurethane based on it exhibits high mechanical properties (with Youngs' modulus of 1011 ± 29 MPa and flexible modulus reached 1833 ± 50 MPa) and excellent reversibility (can be reprocessed at 60 ℃ under 100 kPa in 30 min and completely healed at 40 ℃ in 10 min). Moreover, unlike to many CANs based on hindered urea bonds, our dynamic polyurethanes are highly stable in humid environment or even water solutions due to the slow hydrolysis kinetics. Such high-performance dynamic polyurethane polymers are attractive for many applications.
Azulene is a promising building block for creating innovative polycyclic aromatic hydrocarbons. This study involved the construction of three nonalternant isomers of pentacene by fusing two azulene units, named Az-PH1/2/3. Az-PH1 was initially developed through the rhodium(II)-catalyzed cyclization of bis(N-tosylhydrazone)s. Intriguingly, Az-PH1 was also unexpectedly obtained during a nickel(0)-catalyzed one-step tandem reaction. We investigated the optical and electrochemical properties, aromaticity, and photo-oxidative stability of Az-PH1, comparing it with the well-known pentacene using density functional theory, electrochemical, and photophysical tests. Our results showed that the azulene-fusing strategy resulted in a molecule with narrow optical bandgaps (2.046 eV) and a long half-life time under ambient air conditions.
Quinoidal π-conjugated structures, a kind of fundamental subunits for organic π-systems, may produce some intriguing optical, electronic and magnetic properties of polycyclic hydrocarbons (PHs). Herein, we report two thienothiophene-centered ladder-type polycyclic molecules (1 and 2), which possess one quinoidal thienothiophene moiety and two para-quinodimethane (p-QDM) subunits, respectively. As theoretically and experimentally studied, while 1 is a fully closed-shell molecule, 2 owns an open-shell structure along with partial contribution of tetraradical state that is induced by the resonance of p-QDM. Moreover, although 2 has a larger π-conjugated skeleton and open-shell electronic state, it exhibits larger bandgap and blue-shifted absorption. On the other hand, the reversible oxidation activity of 1 enables the preparation of its dication, and the studies on its single-crystal and aromatic structures demonstrate that its two positive charges are delocalized onto the oxygen atoms, thus achieving fully π-extended structure and near-infrared absorption. This study not only gains insight into quinoidal π-subunits, but also provides an important basis for the development of antiaromatic and open-shell π-electron materials.
Surface fluorination of conventional polymers can give them desirable surface properties similar to the expensive and difficult-to-process fluoropolymers. However, traditional surface fluorination techniques often require toxic reagents and special equipment. Here, we report a simple and effective polymer surface fluorination method by using safe and inexpensive perfluoro-2-methyl-3-pentanone (PFMP, C2F5C(O)CF(CF3)2) and UV irradiation. This method is applicable to various polymer materials, and generates nanometer-thick fluorinated layer on the outermost surface, significantly changing their surface properties without changing the surface morphology.
It is of great interest to make a degradable material widely tailorable to replace petroleum-derived products among diverse applications. Here, we report the construction of a new multi-purpose degradable material for the first time via a simple ternary copolymerization system comprising ε-caprolactone (ε-CL), cyclohexane oxide (CHO) and CO2. Under low pressure of 1 bar ~5 bar, the ring-opening polymerization (ROP) of ε-CL and ring-opening copolymerization (ROCOP) of CO2 and CHO can simultaneously proceed. The carbonate units are randomly distributed on the polymer chain. These random terpolymers have controllable molar mass (10–106 kDa) and compositions (4–33 mol% CO2). And the obtained materials show large-span tunability from tough plastic to elastomer and even adhesive.
Developing platinum-group-metal (PGM) catalysts possessing strong metal-support interaction and controllable PGM size is urgent for the sluggish oxygen reduction reaction (ORR) in proton-exchange membrane fuel cells. Herein, we propose an in-situ self-assembled reduction strategy to successfully induce highly-dispersed sub-3 nm platinum nanoparticles (Pt NPs) to attach on resin-derived atomic Co coordinated by N-doped carbon substrate (Pt/CoSA-N-C) for ORR. To be specific, the interfacial electron interaction effect, along with a highly robust CoSA-N-C support endow the as-fabricated Pt/CoSA-N-C catalyst with significantly enhanced catalytic properties, i.e., a mass activity (MA) of 0.719 A/mgPt at 0.9 ViR‑free and a reduction of 24.2% in MA after a 20,000-cycles test. Density functional theory (DFT) calculations demonstrate that the enhanced electron interaction between Pt and CoSA-N-C support decreases the d-band center of Pt, which is in favor of lowering the desorption energy of *OH on Pt/CoSA-N-C surface and accelerating the formation of H2O, thus enhance the instinct activity of ORR. Furthermore, the higher binding energy between Pt and CoSA-N-C compared to Pt and C indicates that the migration of Pt has been suppressed, which theoretically explains the improved durability of Pt/CoSA-N-C. Our work offers an enlightenment on constructing composite Pt-based catalysts with multiple active sites.
Glioblastoma multiforme (GBM) is the most common malignant primary brain tumor in adults. The precise identification and distinction of GBM heterogeneity from surrounding brain parenchyma at the cellular level and even at the tissue level are important for GBM therapy. In this study, GBM cells are distinguished from normal astrocytes and non-central nervous system (CNS) tumor cells by surface-enhanced Raman scattering (SERS) based on gold nanoshell (SiO2@Au) particles and support vector machine (SVM) algorithm. In addition, the gold nanoisland (AuNI) SERS substrates are further developed and explored for accurate detection of GBM at the tissue level. The distinction between glioma and trauma tissues, identification of different tumor grades, and IDH mutation are realized with the assistance of orthogonal partial least squares discriminant analysis (OPLS-DA) in a rapid, non-invasive, and convenient method. The results show that the developed SERS-based analytical method has the potential for practical application for the detection of GBM at the single-cell and tissue levels and even for real-time intraoperative diagnosis.
Zinc-based batteries (ZBs) have been deemed as a potential substitute for lithium-ion batteries due to its unique advantages of abundant resources, low cost and acceptable energy density. Despite great progress in designing electrode materials has been made, the development of high-performance ZBs still remain challenges, such as the dendrite growth of zinc anode, hydrogen evolution reaction, limited electrochemical stability window, water evaporation and liquid leakage. Gel polymer electrolytes (GPEs), including hydrous GPEs with low content of active water and anhydrous GPEs without the presence of water, are proposed to avoid these problems. Furthermore, employing GPEs is conductive to fabricate flexible devices owing to the good mechanical strength. To date, most of researches focus on discovering new GPEs and exploring its application on flexible or wearable devices. Recent reviews also have outlined the polymer matrixes and advances of GPEs in various battery systems. Given this, herein, we seek to summarize the gelation mechanisms of GPEs, involving physical gel of polymer, chemical crosslinking of polymer and chemical polymerization of monomers. Peculiarly, the preparation methods are also classified. In addition, not only the features and central conundrum of GPEs are analyzed but also the corresponding strategies are discussed, contributing to design GPEs with ideal properties for high-performance ZBs.
Microbial fuel cells (MFCs) have a simple structure and excellent pollutant treatment and power generation performance. However, the slow kinetics of the oxygen reduction reaction (ORR) at the MFC cathode limit power generation. The electrochemical performance of MFCs can be improved through electrocatalysis. Thus far, metal-based catalysts have shown astonishing results in the field of electrocatalysis, enabling MFC devices to demonstrate power generation capabilities comparable to those of Pt, thus showing enormous potential. This article reviews the research progress of meta-based MFC cathode ORR catalysts, including the ORR reaction mechanism of MFC, different types of catalysts, and preparation strategies. The catalytic effects of different catalysts in MFC are compared and summarized. Before discussing the practical application and expanded manufacturing of catalysts, we summarize the key challenges that must be addressed when using metal-based catalysts in MFC, with the aim of providing a scientific direction for the future development of advanced materials.
Diagnostic C9orf72 hexanucleotide repeat expansions (C9-HRE) is essential for the early and accurate diagnosis of amyotrophic lateral sclerosis (ALS) and will provide support for the prognosis and gene therapy of ALS. In the present study, by combining catalytic hairpin assembly (CHA) with Mycobacterium smegmatis porin A (MspA) nanopore, a new nanopore-based strategy for the detection of C9-HRE was reported. Less than 30 repeats of C9-HRE could be detected via this method, and the results have the potential to help distinguish between patients and healthy individuals. Moreover, the method demonstrated its great specificity for C9-HRE by identifying other repeat expansions. Given the high selectivity, this approach had been successfully used to detect C9-HRE in cell and blood samples with high accuracy. This detection strategy is user-friendly and has a strong anti-interference ability, thus providing a powerful tool for clinical diagnosis.
No. 86 Xueyuan South Road, Haidian District, Beijing
010-62662699(Operation and Technical Support)
qkjq@cast.org.cn
Copyright © 2025 China Association for Science and Technology. All rights reserved. For all open access content, the relevant licensing terms apply.
Sponsored by the Office of the Leading Group for Cybersecurity and Informatization of CAST, and supported by Science and Technology Review Publishing House
