最新刊期
卷 53 ， 期 6 ， 2022
- 摘要：The non-degradable nature of petroleum-derived plastics causes serious environmental pollution, which has become a global public crisis. Hong and co-workers develop an effective and robust strategy utilizing isomerization-driven irreversible ring-opening polymerization (IROP) for converting "non-strained" five-membered γ-thionobutyrolactone into poly(γ-thionobutyrolactone) (PTBL). The IROP can be conducted at industrially relevant temperature of 80-100 ℃ and afford PTBL with high molecular weight, which is commonly inaccessible by the other polymerization methods. Different from most conventional ring-opening polymerizations, this IROP approach is thermodynamically driven by the S/O isomerization rather than the ring strain. PTBL can be easily degraded into non-strained γ-butyrothiolactone with added value, thus establishing a sustainable model for polymer recycling. PTBL exhibits a wide range of notable properties resembling commercial low density polyethylene, making it promising for many potential applications.关键词：Isomerization reaction;Non-strained ring;Ring-opening polymerization;Polyethioesters;Sustainable polymers
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发布时间：2024-10-08
Research Highlight
- 摘要：Big data approach, a new paradigm for data-driven wisdom paces together with conventional experimental, theoretical and simulation ways. The core in the application of big data study in material researches is at the composition-process-structure-property-performance relationship (CPSPPr). The digitalization and computational efforts, concepts, tools and resources to enable the subterms in the CPSPPr to cover fundamental research and scalable production will be presented. The big data approach can fully utilize the merits for the "black-box" of emerging machine learning algorithms, which allows for the construction of much more quantitative correlations beyond conventional rationality. It provides fantastic wisdom in reward for the discovery and the manufacture of new materials from the inherently frustrated multiple scales, broadly distributed, weak but accumulatively-strong response of polymers. We hereby reviewed such representative progresses in the innovation of polymer materials wholly or partially using big data approach in the last four years. These progresses are grouped as: polymer synthesis and self-assembly, mechanical and thermal properties, optic-electric-magnetic-acoustic properties and membranes for separation. The overall progress for the application of big data approach in the research of polymer materials is lagging in the comparison with that in inorganic or small-molecular materials. We then enumerated a number of challenges and possible short-term breakthroughs before the dawn of burst for big data in the reshape of the research and the production of polymer materials.关键词：polymer material;big data;composition-process-structure-property-performance relationship;computer aided material design
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发布时间：2024-10-08 - 摘要：The goal of protein structure prediction is to determine, usually based on computer simulations or calculations, the three dimensional structure from a given amino acid sequence. Protein structure prediction is important since the 3D protein structure will further determine its biological functions. Nevertheless, traditional prediction method based on physics can only effectively deal with short proteins with the low accuracy. In the past decade, data-driven methods and methods based on genetic knowledge have become popular. This review covers several important developments about the deep-learning methods on protein prediction in the past ten years. Considering the education background of readers of the journal, we will first present a self-consistent but concise introduction about the prerequisite concepts and methods, related with genetic information and basis of deep learning, to understand the deep-learning methods for the protein structure prediction. The prerequisite concepts and methods include position-specific scoring matrix (PSSM), multiple sequence alignment (MSA), contact map, distogram, protein data bank (PDB), critical assessment of protein structure prediction (CASP), template modelling score (TM score), universal approximation theorem and several important types of neural network closely related with protein structure prediction. Then, we compared the two most popular methods employed in the data-driven protein structure prediction, template-based method and template-free method. As for the deep-learning methods, the AlphaFold method from Deepmind will be specially discussed, which has achieved the prediction accuracy comparable to median or low experimental accuracy that even rendered some people to think that it has resolved the protein structure prediction problem to some extent. Nevertheless, all the above methods are too "overwhelming" and not friendly for beginners. Therefore, this review also introduced a simplest structure prediction problem, HP protein prediction problem, together with the corresponding deep-learning solution, strongly-correlated neural network, to novices in this area.关键词：Protein folding;Deep learning;Neural network;Structural Prediction
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发布时间：2024-10-08 - 摘要：The materials genome approach (MGA), which can accelerate the research and development of new materials via combining computer technology, database technology, and experiments, has attracted considerable attention from academia and industry. However, establishing the structure-property relationship of polymer is more complicated than those of metal and inorganic materials because of the complex structural features such as chain architecture, chain configuration, chain conformation, and chain aggregation. The difficulty in building the structure-property relationship has hindered the development of MGA in polymers. Recently, there have been increasing studies on the rational design of advanced polymers by MGA. This review summarizes research progresses on the MGA of polymer, including establishing structure-property relationships that can predict polymer properties, exploring the vast chemical space of polymers, and rationally designing polymer structures. Calculating the key features that correlate with the desired properties from data mining is one of the ways to screen promising polymers. Alternatively, machine learning can construct structure-property relationships automatically based on databases. The model based on machine learning can apply to the forward and inverse design of advanced polymers. These two prevalent methods are presented. The review systematically introduces the methods of data mining or model construction and the ideas of screening different types of polymers by using these models and focuses on the ideas behind method construction and material screening and the solutions to various problems. In addition, the challenges faced by the development of polymer MGA are also outlined. To push forward the research on polymer MGA, we suggest paying more attention to introducing more efficient machine learning technology, establishing more comprehensive polymer databases, and developing high-throughput experimental technology in the future.关键词：Material genome approach;Polymer;Machine learning;Simulation
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发布时间：2024-10-08
Review
- 摘要：Organic-polymer photoresist is the medium and carrier of micro manufacturing by two-color sensitive direct laser writing technology, which directly affects the accuracy and authenticity of the micro structures. In this work, polyvinylpyrrolidone (PVP) is introduced into pentaerythritol triacrylate (PETA) to control the viscosity, mechanical strength, volume shrinkage and polymerization rate of photoresist. The results show that hydrogen bond is formed between PVP and PETA, which can be used as a crosslinking site to improve the crosslinking degree of photoresist. Meanwhile, the introduction of PVP also increases the viscosity of the system, reduces the oxygen inhibition, and finally effectively improves the photo-polymerization conversion rate (30.1%) of PETA in photoresist, obtaining higher sensitivity and lower polymerization threshold (6.5 mW, 20 wt% PVP). In addition, the PVP sharply reduces the volume shrinkage of photoresist from 18% to 3%, greatly weakening the internal stress of the fabricated structure, thus improving the lithography performance of micro structures. Finally, the minimum linewidth of PVP composited photoresist can reach 48 nm, which has higher uniformity and regularity than that of photoresist without PVP. Thus, this work is of great significance for high-precision and high-quality micro manufacturing and various applications.关键词：Polyvinylpyrrolidone;Photoresist;Two-color sensitive;Direct laser writing
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发布时间：2024-10-08 -
Flexible Transparent Electrode and Capacitance Sensor Based on Bionic-MXene Fiber Conductive Network
摘要：With the continuous development of intelligent wearable devices, flexible electronic products that can perform intelligent camouflage and stealth have attracted more and more attention, among which flexible transparent electrodes play an increasingly important role in the field of intelligent camouflage and stealth devices. Biomimetic to nature is an ideal choice to self-assemble micro-units into macro-structure assembly. In nature, most leaf veins have hierarchical interconnected structures. These different levels of veins form an interconnected interwoven network structure. In order to develop intelligent camouflage devices with excellent performance, the flexible transparent electrodes were prepared by pretemplate method inspired by leaf veins. The transparent electrodes were developed with a transparent conductive mesh structure by self-assembling metal carbide/nitride (MXene) on the surface of the vein fibers. The interaction between the hydroxyl groups on the surfaceof the veins and the active groups on the surface of the conductive material greatly improves the surface bonding strength of the conductive material and the substrate. While maintaining high transparency, the transparent electrode induces MXene to evenly construct ordered conductive network on the flexible vein, effectively avoiding the "trade off" effect between photoelectric characteristics, and has excellent stability and durability. The FTEs with a sheet resistance of 11.4 Ω/sq, a transmittance of 80.6%, have excellent mechanical flexibility with a negligible increase in sheet resistance even under 1000 cyclic bending tests. The transparent capacitive sensor was successfully prepared with the transparent electrode, with the sensitivity up to 0.09 kPa-1, and the relative capacitance remains essentially unchanged after 1000 cycles. The transparent capacitance sensor has good pressure detection and non-contact monitoring function. As an intelligent stealth camouflage electronic device, it has excellent sensing performance and stability, and can monitor human movement signals in an imperceptible state. The flexible transparent electrode and transparent capacitive sensor possess great potential in the field of smart wearables and wearable camouflage electronics.关键词：Flexible transparent electrode;Ordered conductive network;Flexible transparent capactive sensor;Intelligent invisibility camouflage;Movement monitoring- 403
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发布时间：2024-10-08 - 摘要：Although chemotherapy is currently the most widely used treatment for colon cancer, it is still severely limited by poor therapeutic efficacy and inevitable side effects. Specially, tumor cells gradually appear insensitive for chemotherapeutics after repeated drug mediation. The overexpression of P-glycoprotein (P-gp) in tumor cells, which significantly reduces intracellular drug concentration, is the most popular cause of chemotherapy resistance. Here, we designed and prepared gut microbial glucuronidase-responsive glycyrrhizin micelles for delivery of a chemotherapeutic drug and in situ generation of P-gp inhibitor to overcome colon cancer chemotherapy resistance and to enhance the chemotherapy effect. Glycyrrhizin (GL) micelles prepared by self-assembly were used to load hydrophobic drug doxorubicin (DOX). Sequentially, chitosan (CS) was electrostatically crosslinked on the surface of GL micelles to construct DOX@GLCS micelles. The results showed that micelles were about 165 nm with promising dispersibility and stability. With the presence of glucuronidase secreted by gut microbes, DOX@GLCS micelles were degraded to release DOX. Meanwhile, GL was converted into glycyrrhetinic acid (GA), which was a potent P-gp inhibitor to decline P-gp expression and enhance intracellular drug accumulation. Compared to free DOX, DOX@GLCS micelles exerted suprior cytotoxicity to colon cancer CT26 cells as well as DOX-ressitant CT26 cells. In two orthotopic colon cancer-bearing mice models, oral administration of DOX@GLCS micelles significantly inhibited tumoral P-gp expression and suppressed tumor growth. Moreover, owing to the regulatory effect of prebiotic chitosan, DOX@GLCS treatment effecively repaired damaged intestinal mucosa. Overall, this gut microbiota-responsive drug delivery system provides a new perspective for augmented CRC chemotherapy.关键词：Gut microbiota;Glycyrrhizin;Glycyrrhetinic acid;P-gp;Chemotherapy
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发布时间：2024-10-08 - 摘要：The biotin-avidin reaction system has shown remarkable advantages in immunoassays and biomedical fields due to its high specificity, excellent sensitivity and stability. The ability to generate biotinylated surface with gradient features would further promote the potential application of the biotin-avidin system in various fields ranging from high-throughput analysis to multifunctional biological surface. Here, based on the micropatterned polymer brushes functionalized with azido groups, a promising method was presented for fabricating the biotinylated gradient surfaces. Micropatterned poly(2-(2-azido-2-methyl-1-oxopropoxy) ethyl methacrylate) (PAMEMA) brushes bearing azido groups were fabricated through employing a digital mirror device (DMD)-based light modulation technique to regulate a surface-initiated photoinduced atom transfer radical polymerization (Photo-ATRP) process. X-ray photoelectron spectroscopy (XPS) and time of flight-secondary ion mass spectrometry (TOF-SIMS) measurements were performed to characterize the surface elemental composition of silicon substrates micropatterned with PAMEMA brushes, whose results indicate the spatially selective distribution of azido groups. The terminal azido groups of PAMEMA brushes could provide reactive sites for covalent immobilization of DBCO-PEG4-biotin through the highly specific orthogonal "click" reaction, leading to the biotinylation of PAMEMA brushes micropatterned surface. The streptavidin-fluorophore conjugate binding experiment was performed to characterize the distribution of biotins on the patterned surface. The fluorescence characterizations demonstrated the functionality of the micropatterned PAMEMA brushes with various thicknesses to regulate the spatial density of immobilized biotins, which resulted in the successful creation of biotinylated gradient surfaces with various complicated structures. The research extends the application of polymer brush micropattern in functional gradient surfaces preparation, and provides fundamental technical support for expanding biotinylated gradient surfaces applications in high-throughput detection chips and combinatorial chemistry.关键词：Poly(2-(2-azido-2-methyl-1-oxopropoxy) ethyl methacrylate) brush micropattern;Azido group;Click reaction;Biotinylated gradient surface
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发布时间：2024-10-08 - 摘要：Superhydrophobic micro-/nanostructured surfaces are widely used in the fields of self-cleaning, anti-icing, anti-bacterial and flexible sensor, but there are still some challenges in the preparation methods of these surfaces. In this work, the polypropylene (PP) surfaces with nanostructure arrays were prepared using the hot compression molding with anodic aluminum oxide (AAO) templates. With the ultrasonic-assisted treatment, the nanostructure was transformed onto micro-/nanostructure due to the ultrasonic cavitation effect. The superhydrophobic property of micro-/nanostructured surface was improved after ultrasonic treatment, the contact angle increased from 152.3° to 160.0°, the rolling angle decreased from 11.5° to 1.8°, and the surface adhesion decreased from 75 μN to 38 μN. Moreover, the self-cleaning performance of the micro-/nanostructured PP surface was also better than that of the nanostructured PP surface. The template method combining with the ultrasonic-assisted treatment is convenient, cheap, and effective in the preparation of superhydrophobic micro-/nanostructured surfaces, expecting promising applications in industrial production.关键词：Compression molding;Anodic aluminum oxide;Ultrasonic-assisted treatment;Micro-/nanostructure;Superhydrophobic
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发布时间：2024-10-08 - 摘要：In this work, human immunoglobulin G (Ig G) is selected as the template, and the strategy of combining template immobilization and surface imprinting technology is used to prepare a new and efficient protein imprinting material (MIPs). In order to increase the separation effect of MIPs, the metal organic framework (UIO-66) is fabricated and used as a carrier for protein immobilization. Meanwhile, in order to improve the recognition of imprinting materials, zwitterionic monomers participate in the preparation of MIPs to improve their recognition ability. The research results showed that the UIO-66 crystal presented a regular octahedral shape, and the as-prepared MIPs exhibited an excellent specific surface area (362.5 m2/g). In addition, by optimizing the amount of zwitterionic monomer, it was found that the best recognition could be obtained when it accounted for 20% of the total mass of the functional monomer. The adsorption experiments also demonstrated that UIO-66@MIPs could achieve saturated adsorption in an Ig G solution with a concentration of 2.0 mg/mL, and its saturated adsorption capacity reached 217.4 mg/g with the imprinting factor of 2.48. Furthermore, the adsorption equilibrium time of UIO-66@MIPs was about 50 min. Moreover, the specific recognition experiment of UIO-66@MIPs showed that compared with non-imprinted materials, it could separate Ig G more effectively from the protein mixture solution, proving their excellent specific recognition capability.关键词：Protein imprinting technology;Metal-organic framework;Zwitterionic monomer
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发布时间：2024-10-08 - 摘要：Soluble polyimide containing metal coordination crosslinking network was synthesized through molecular structure design. Based on the coordination crosslinking between Cu2+ and the lateral carboxyl group of polyimide, the mobility of polyimide chain in solid state was limited and the Tg of the material was significantly improved. The Tg of the original polyimide is about 320 ℃, while the Tg of coordination crosslinked polyimide PI-Cu50% can reach about 362 ℃. After coordination with Cu2+, the initial "push-pull" electronic mode of polyimide is destroyed, the existing state of electrons in the main chain was changed, and the fluorescence intensity of polyimide was weakened. Meanwhile, Cu2+ has an aspherical symmetrical electron cloud structure, resulting in additional crystal field stability energy (CFSE) and strong Jahn teller effect (JTE) when Cu2+ coordinates with organic ligands, so that the coordination bond can exist stably in organic solvents, After the introduction of copper chloride, crosslinking network based on Cu2+ coordination was formed in the molecular structure of polyimide which greatly improves the solvent corrosion resistance of the films. The original polyimide film can be completely dissolved after soaking in strong polar solvents such as N,N-dimethylformamide (DMF), N-methylacetamide (DMAc) and N-methylpyrrolidone (NMP) and standing at room temperature for two days, while the mass residue rate of the coordination crosslinked polyimide film PI-Cu50% can still be as high as 80% after soaking in strong polar solvents such as DMF and DMAc at room temperature for 48 h. Due to the decarboxylation crosslinking reaction of carboxyl group at about 400 ℃, the Td5 of polyimide containing carboxyl group is low, and the thermal stability of carboxyl group was significantly improved when coordinated with Cu2+, so the Td5 of polyimide was improved. Moreover, the introduction of metal ion coordination into the polyimide molecular structure also improved its mechanical properties, and the tensile strength of film increased from 93 MPa to 128 MPa. This study provides a new way to develop high-performance soluble polyimide materials.关键词：Polyimide;Metal ligand coordination;Crosslinked polymer;Solvent resistance;Mechanical property
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发布时间：2024-10-08 - 摘要：Polyphenylene sulflde (PPS) possesses the excellent heat resistance, flame resistance, chemical resistance and good mechanical properties. However, the poor UV-resistance properties of PPS are an important obstacle for PPS usage in some high-end areas. In this study, TiO2/phenyltriethoxysilane (PTES) nanoparticles were prepared from PTES and TiO2 by sol-gel method, and a series of characterizations were employed to investigate TiO2/PTES nanoparticles. Furthermore, TiO2/PTES/PPS composite films with different nanoparticle doping amounts were prepared. The effects of TiO2/PTES nanoparticles on PPS UV resistance were investigated, and it was found that the loading of PTES realized benzene functionalization on the surface of TiO2 nanoparticles and that TiO2/PTES nanoparticle can effectively suppress the photocatalytic activity in comparison with TiO2. After 192 h of UV radiation, the physicochemical structure of TiO2/PTES/PPS composite film did not change, and even the color of composite film did not significantly deepen or turn yellow. When 2.0 wt% of TiO2/PTES nanoparticles were introduced into PPS matrix, the optimal ultraviolet resistant properties of composite films were achieved, and the stress strength retention rate and breaking elongation retention rate after UV irradiation 192 h were 93.75% and 94.00%, respectively. Herein, our UV-resistance method can pave the way toward the application of PPS in the field of extreme environment.关键词：Polyphenylene Sulflde;Phenylsiloxane;TiO2;Ultraviolet resistance;Photocatalytic activity
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发布时间：2024-10-08 - 摘要：Water-soluble poly(p-phenyleneethynylene-alt-m-phenyleneethynylene)s (meta-PPEs) can wrap single-walled carbon nanotubes (SWCNTs) helically to improve the solubility of SWCNTs and realize highly selective dispersion. In order to deeply understand the formation mechanism of such well-defined supermolecular structure, we prepared the composites of SWCNTs and the cationic water-soluble meta-PPE-N+Et2Me in DMSO/H2O mixed solvents with different ratios. The effects of polymer structure and composition of mixed solvents on the morphology and stability of the composite structure were deeply explored. Studies on the ultraviolet-visible-near infrared absorption spectroscopy, fluorescence spectroscopy, transmission electron microscopy, Raman spectroscopy and infrared spectroscopy showed that, when the ratio of DMSO was 70%, the polymer exhibited a sudden change from random coil to helical conformation. At this time, the driving force to self-assemble into helical conformation was relatively large, so the polymer wrapped SWCNTs helically in the process of forming a helical hydrophobic cavity itself, and the hydrophobic effect and π-π interaction were further enhanced to form a stable composite. However, no obvious helical wrapping supermolecular structure was formed in the mixed solvents with other ratios. These results will provide some theoretical guidance for the controllable modification and application improvement of SWCNTs.关键词：Single-walled carbon nanotubes;Water-soluble poly(phenyleneethylene)s;Composite;Helical wrapping
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发布时间：2024-10-08
Research Article
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