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Science China Chemistry 2024年第8期67卷 2719-2727页

作者： Siyang Lin Tianqi Ren Xianyu Meng Wenxin Kang Jinbao Guo Key Laboratory of Carbon Fibers and functional polymers Ministry of EducationCollege of Materials Science and EngineeringBeijing University of Chemical TechnologyBeijing 100029China

Solid materials with dynamically tunable circularly polarized luminescence(CPL) feature higher security levels and devicefriendly characteristics, showing great superiority in the field of information technology and anti-counterfeiting. To address the limited photoisomerization of fluorescent photoswitch in CPL-active solid materials, here a cholesteric liquid crystal elastomer(CLCE) containing a hydrogen-bonded(H-bonded) polymerizable fluorescent switch AHBA-PSD is prepared. Owing to the good flexibility and low glass-transition temperature of CLCE, AHBA-PSD shows a fast and fully reversible photocyclization/cycloreversion with fluorochromic behavior in CLCE. Further, by controlling the spectral overlapping area between the emission and reflection bands, the CLCE exhibits a strong CPL with a g_(lum) value of up to 0.76 accompanied by a reversible phototunable CPL signal. Meanwhile, the H-bond helps to stabilize the mechanical property, and the force-induced switching-off of CPL signal could be achieved due to the destroyed helical structures by external force. Finally, an automatically-recognized identification card with abundant chiroptical information is demonstrated.

关键词： cholesteric liquid crystal elastomer circularly polarized luminescence fluorescent photoswitch diarylethene photoismerization

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Thermal stability improvement and microstructure optimization of high cobalt content Nd-Fe-B magnets via terbium grain boundary diffusion

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Journal of Rare Earths 2024年第8期42卷 1531-1538页

作者： Jiyuan Xu Ruiyang Meng Jing Liu Jiateng Zhang Rui Han Yikun Fang Shengzhi Dong Wei Li division of functional materials Research Central Iron and Steel Research Institute

The substitution of Fe by Co in the 2:14:1 phase is an effective method to increase the Curie temperature and enhance the thermal stability of the Nd-Fe-B ***,the accumulation of Co ele ment at the grain boundaries（GBs） changes the GBs from nonmagnetic to ferromagnetic and causes the thinlayer GBs to become rare,In this paper,the method of diffusing Tb element was chosen to improve the microstructure and temperature stability of high-Co *** original sintered Nd28.5Dy3-CoxebalM0.6Bi（x=0,6 wt%,12 wt%;M = Cu,Al,Zr） magnets with different Co contents were diffused with Tb by grain boundary diffusion（GBD）.After GBD,high-Co magnets exhibit more continuously distributed thin-layer GBs,and their thermal stability is significantly *** high-Co magnets（x=6 wt%）,the absolute value of the temperature coefficient of coercivity decreases from 0.603%/K to0.508%/K in the temperature range of 293-413 K,that of remanence decreases from 0.099%/K to 0.091%/K,and the coercivity increases from 18.44 to 25.04 *** electron microscopy（TEM）characterization reveals that there are both the 1:2 phase and the amorphous phase in the high-Co magnet before and after GBD,EDS elemental analysis shows that Tb element is more likely to preferentially replace the rare earth elements in the 2:14:1 main phase than in the 1:2 phase and the amorphous *** concentration of Tb at the edge of the main phase is much higher than that in the 1:2phase and amorphous phase,which is beneficial to the improvement of the *** preferential replacement of Tb elements at the edge of the 2:14:1 phase and thin-layer GBs with a more continuous distribution are synergistically responsible for improving the thermal stability of high-Co *** study indicates that GBD is an effective method to improve the microstructure and thermal stability of high-Co magnets.

关键词： Coercivity Grain boundary diffusion Microstructure Nd-Fe-B magnets Rare earths Thermal stability

Polarization-driven multifunctional organohydrogels with strain sensitivity toward electromagnetic wave absorption

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Nano Research 2024年第6期17卷 5688-5697页

作者： Yunfei Zhang Lei Zhang Bingqian Zhou Yishan Gao Baoliang Zhang School of Chemistry and Chemical Engineering Northwestern Polytechnical UniversityXi’an 710072China Shaanxi Engineering and Research Center for functional polymers on Adsorption and Separation Sunresins New Materials Co.Ltd.Xi’an 710072China

Rapid advancements in flexible electronics and military applications necessitate high-performance electromagnetic wave(EMW)*** huge breakthroughs in achieving high-attenuation microwave absorption,conventional EMW absorbing materials have single function and ambiguous absorption ***,numerous gel-type absorbers are fabricated by introducing“regulators”into poly(acrylamide-co-acrylic acid)(P(AM-co-AA))networks through radical polymerization in a glycerol-water mixed *** dielectric constant and EMW absorption performance of the gels are precisely predicted by adjusting monomer concentration,the ratio of glycerol/water,and the content of the ***,A_(6)G_(20)T_(20)-2 exhibits promising absorption performance with a minimum reflection loss(RL_(min))of-33.8 dB at 12.4 *** effective absorption bandwidth(EAB)covers the entire X-band(8.2-12.4 GHz)at a thickness of 2.7 mm.A_(6)G_(20)T_(20)-2 also has sensitive deformation responses and excellent tensile strength,adhesiveness,self-healing and anti-freezing ***,this work not only provides insight into the polarization loss mechanism of the gels as the result of high correlation between EMW absorbing properties and molecular polarization,but also offers an important reference for developing functional protective materials because of the rich functionalities and efficient protective capabilities of the gels.

关键词： organohydrogels molecular polarization microwave absorption strain sensor

Complementary multicolor electrochromic devices with excellent stability based on porous tin oxide nanosheet scaffold

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Nano Research 2024年第4期17卷 3035-3042页

作者： Chenchen Bian Jinhui Wang Huanhuan Liu Yin Yan Ping Zhang Weilong Yang Sensen Jia Xiaodan Guo Guofa Cai Key Laboratory for Special functional materials of Ministry of Education National&Local Joint Engineering Research Center for High-Efficiency Display and Lighting TechnologySchool of Materials and Engineeringand Collaborative Innovation Center of Nano Functional Materials and ApplicationsHenan UniversityKaifeng 475004China

Electrochromic devices(ECDs)have been extensively investigated as promising candidates in broad cutting-edge applications,such as smart windows,electronic labels,adaptive camouflage,***,they have suffered from either inadequate color variations or poor cycling stability for a long ***,we developed a general strategy to boost the cyclic stability and enrich the color variations of ECDs by scrupulous design of the composition and nanostructure of electrodes,in which porous tin oxide(SnO_(2))nanosheets serve as the scaffold and typical metal oxides or conducting polymers as the active electrochromic *** electrochromic composite materials,including polyaniline(PANI)@SnO_(2),V2O5@SnO_(2),and WO_(3)@SnO_(2) heterostructured nanoarrays were prepared by the facile wet-chemical *** composite electrodes exhibit remarkable electrochromic performances,e.g.,superior cycling stability(more than 2000 cycles),rich color variations(more than 5 colors for PANI@SnO_(2)),and enlarged optical *** excellent performances account for the heterogenous porous nanoarrays,which not only facilitate the intercalation/extraction of ions but also relieve the stress generated during the electrochemical *** addition,diverse prototypes of complementary multicolor ECD with excellent cycling stability(over thousands of cycles)and rich color variations(8 colors)were realized for the first *** believe that our work put forward a general strategy for developing high-quality multicolor complementary electrochromic devices.

关键词： electrochromism tin oxide metal oxide cycling stability multicolor complementary device

Mechanisms of inclusion-induced pitting of stainless steels:A review

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Journal of materials Science & Technology 2024年第1期168卷 143-156页

作者： Yangting Sun Xin Tan Rulei Lan Guoyong Ran Jin Li Yiming Jiang Department of materials Science State Key Laboratory of Molecular Engineering of PolymersFudan UniversityShanghai 200438China

Pitting is a common type of localized corrosion in passive alloys that can cause rapid failure of material or *** the case of stainless steels,non-metallic inclusions have been identified as the most susceptible sites for pitting,and have therefore garnered significant *** review critically ex-amines the issue of how inclusions induce pitting,with a particular focus on three mechanisms:sponta-neous dissolution of inclusions,active dissolution of Cr-depleted regions,and propagation of microcracks at the inclusion-matrix *** researchers have made significant strides in understanding these mechanisms over the past few decades,many gaps and controversies *** such as the ini-tial driving force of inclusion dissolution and factors affecting Cr-depleted regions require further ***,some old concepts and methods need to be revised to arrive at more credible *** review aims to delve deeply into these important issues and provide inspiration for future research.

关键词： Pitting Inclusion Stainless steel Localized corrosion MnS

Reversible isomerization of donor-acceptor Stenhouse adduct derivatives in water through dendritic confinement

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Science China Chemistry 2024年第5期67卷 1636-1646页

作者： Jiaxing Zhang Qingyun Zhao Xinyan Su Afang Zhang Wen Li International Joint Laboratory of Biomimetic and Smart polymers School of Materials Science and EngineeringShanghai UniversityShanghai 200444China

Modulating reversible isomerization of hydrophobic dyes in aqueous solutions is greatly desired. Here we report on reversible isomerization of solvatochromic donor-acceptor Stenhouse adducts(DASAs) in water through the confinement from dendritic oligoethylene glycols(OEGs). Dendronization of DASAs with dendritic OEGs affords them characteristic thermoresponsiveness. These dendronized DASAs spontaneously isomerize in water from hydrophobic linear state into hydrophilic cyclic state at room temperature due to the strong hydration. However, hydrophobic microenvironment through thermally dehydration and collapse of the dendritic OEGs at elevated temperatures confines hydration of the DASA moieties and mediates their interactions with the collapsed hydrophobic OEG domains, affording their isomerization recovery in water efficiently from the hydrophilic cyclic state into the hydrophobic linear state. The confinement-mediated reversible isomerization of DASA moieties in water can be repeated through alternative photo-irradiation and thermal dehydrations, exhibiting excellent fatigue resistance.

关键词： dendrimers donor-acceptor Stenhouse adducts isomerization confinement thermoresponsiveness

Impact of Carbon Chain Structures in the Backbone on the Flexibility of Modified Polyarylene Sulfide Resins: Molecular Dynamics Simulations and Mesoscopic Analysis

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Chinese Journal of Polymer Science 2024年第4期42卷 544-557页

作者： Chi Zhang Rong Liu Jing-Yuan Liu Wen-Wei Jiang Key Laboratory of Fine Chemical Engineering and functional materials School of Chemical EngineeringSichuan UniversityChengdu610065China

In the domain of high-performance engineering polymers, the enhancement of mechanical flexibility in poly(phenylene sulfide) (PPS) resins has long posed a significant challenge. A novel molecular structure, designated as PP-He-IS, wherein imide rings and an aliphatic hexylene chain are covalently incorporated into the PPS backbone to enhance its flexibility, is introduced in this study. Molecular dynamics (MD) simulations are employed to systematically explore the effects of diversifying the backbone chain structures by substituting phenyl units with alkyl chains of varying lengths, referred to as PP-A-IS where “A” signifies the distinct intermediary alkyl chain configurations. Computational analyses reveal a discernable decrement in the glass transition temperature (Tg) and elastic modulus, counterbalanced by an increment in yield strength as the alkyl chain length is extended. Notably, the PP-He-IS variant is shown to exhibit superior yield strength while simultaneously maintaining reduced elastic modulus and Tg values, positioning it as an advantageous candidate for flexible PPS applications. Mesoscopic analyses further indicate that structures such as PP-He-IS, PP-Pe-IS, and PP-Bu-IS manifest remarkable flexibility, attributable to the presence of freely rotatable carbon-carbon single bonds. Experimental validation confirms that a melting temperature of 504 K which is lower than that of conventional PPS, and lower crystallinity are exhibited by PP-He-IS, thereby affording enhanced processability without compromising inherent thermal stability. Novel insights into the strategic modification of PPS for mechanical flexibility are thus furnished by this study, which also accentuates the pivotal role played by molecular dynamics simulations in spearheading high-throughput investigations in polymer material modifications.

关键词： Molecular dynamics simulations Polyarylene Sulfide Main-chain modifications Flexibility Aliphatic hexylene chain

Production of functional materials Derived from Regenerated Silk Fibroin by Utilizing 3D Printing and Biomimetic Enzyme-induced Mineralization

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Chinese Journal of Polymer Science 2024年第3期42卷 299-310,I0005页

作者： Ni Chen Fei-Yu Luo Gong-Wen Yang Jin-Rong Yao Xin Chen Zheng-Zhong Shao State Key Laboratory of Molecular Engineering of polymers Laboratory of Advanced Materials and Department of Macromolecular ScienceFudan UniversityShanghai 200433China

Critical-sized bone defects, commonly encountered in clinical orthopedic surgery, present a significant challenge. One of the promising solutions is to prepare synthetic bone substitute materials with precise structural control, mechanical compatibility, and enhanced osteogenic induction performance, nevertheless the successful preparation of such materials remains difficult. In this study, a two-step technique,integrating an extrusion-based printing process with biomimetic mineralization induced by alkaline phosphatase(ALP), was developed. Initially,a pre-cured hydrogel of regenerated silk fibroin(RSF) with a small quantity of hydroxypropyl cellulose(HPC) and ALP was prepared through heating the mixed aqueous solution. This pre-cured hydrogel demonstrated thixotropic property and could be directly extruded into predetermined structures through a 3D-printer. Subsequently, the 3D-printed RSF-based materials with ALP underwent biomimetic in situ mineralization in calcium glycerophosphate(Ca-GP) mineralizing solution, utilizing the polymer chains of RSF as templates and ALP as a trigger for cleaving phosphate bonds of Ca-GP. The resulting 3D-printed RSF-mineral composites including hydrogel and sponge possessed adjustable compression modulus of megapascal grade and variable hydroxyapatite content, which could be controlled by manipulating the duration of the mineralization ***, these 3D-printed RSF-mineral composites demonstrated non-cytotoxicity towards rat bone marrow mesenchymal stem cells. Therefore, they may hold great potential for applications involving the replacement of tissues characterized by osteoinductivity and intricate structures.

关键词： Silk protein Alkaline phosphatase Extrusion-based printing Biomineralization

When quantum dots meet blue phase liquid crystal elastomers:visualized full-color and mechanically-switchable circularly polarized luminescence

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Light(Science & Applications) 2024年第6期13卷 1210-1220页

作者： Shan Li Yuqi Tang Qingyan Fan Ziyuan Li Xinfang Zhang Jingxia Wang Jinbao Guo Quan Li Key Laboratory of Carbon Fibers and functional polymers Ministry of Educationand College of Materials Science and EngineeringBeijing University of Chemical Technology100029BeijingChina Institute of Advanced materials and School of Chemistry and Chemical Engineering Southeast UniversityNanjing211189China materials Science Graduate Program Kent State UniversityKentOH44242USA CAS Key Laboratory of Bio-Inspired materials and Interfacial Sciences Technical Institute of Physics and ChemistryChinese Academy of Sciences100190BeijingChina

Polymer-based circularly polarized luminescence(CPL)materials with the advantage of diversified structure,easy fabrication,high thermal stability,and tunable properties have garnered considerable ***,adequate and precise tuning over CPL in polymer-based materials remains challenging due to the difficulty in regulating chiral ***,visualized full-color CPL is achieved by doping red,green,and blue quantum dots(QDs)into reconfigurable blue phase liquid crystal elastomers(BPLCEs).In contrast to the CPL signal observed in cholesteric liquid crystal elastomers(CLCEs),the chiral 3D cubic superstructure of BPLCEs induces an opposite CPL ***,this effect is entirely independent of photonic bandgaps(PBGs)and results in a high glum value,even without matching between PBGs and the emission bands of ***,the lattice structure of the BPLCEs can be reversibly switched via mechanical stretching force,inducing on-off switching of the CPL signals,and these variations can be further fixed using dynamic disulfide bonds in the ***,the smart polymer-based CPL systems using the BPLCEs for anti-counterfeiting and information encryption have been demonstrated,suggesting the great potential of the BPLCEs-based CPL active materials.

关键词： circular quantum crystal

受活字印刷启发的可用于信息存储的自愈合荧光液晶弹性体

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Science China materials 2024年第1期67卷 355-362页

作者：高京京丛晓阳汤玉婷郭金宝 Key Laboratory of Carbon Fibers and functional polymers Ministry of EducationCollege of Materials Science and EngineeringBeijing University of Chemical TechnologyBeijing 100029China

信息存储材料的发展在信息社会的进步中起着关键作用.然而,在光寻址记录信息时,通常每次记录信息都需要更换不同的掩模,这在实际应用中极为不便.本文受活字印刷术的启发,开发了一种可作为信息存储和记录介质的自愈合荧光液晶弹性体.该... 详细信息

信息存储材料的发展在信息社会的进步中起着关键作用.然而,在光寻址记录信息时,通常每次记录信息都需要更换不同的掩模,这在实际应用中极为不便.本文受活字印刷术的启发,开发了一种可作为信息存储和记录介质的自愈合荧光液晶弹性体.该薄膜在温和的加热条件下经由简单的两阶段胺-丙烯酸酯aza-Michael反应制备而成.由于α-氰基取代二芳基乙烯荧光分子的光异构化,液晶弹性体薄膜表现出光可调的荧光特性.同时,动态硼酸酯键的引入使其具备了优异的自愈合和可重构形状性能.以上述荧光液晶弹性体薄膜作为存储介质,概念验证性地展示了活字印刷驱动的信息记录,该方法避免了重复更换光掩膜,并延长了存储材料的使用寿命.这项工作为开发易于使用的、可大面积制备的信息存储材料提供了有益的启示.

关键词：信息存储存储材料液晶弹性体存储介质记录介质信息记录自愈合光异构化