MACROMOLECULES
·
2022
·
IF 6.057
Xiaofeng Li,Kuan Yang,Zimo Wang,Yaohan Chen,Yonggang Li,Jing Guo,Jifu Zheng,Shenghai Li,Suobo Zhang
Main-chain non-ether anion-exchange membranes (AEMs) have become a research hotspot in recent years because of their ease of preparation and excellent alkaline stability. However, owing to the limitations of the types of monomers and polymerization mechanisms, preparing main-chain non-ether AEMs with controllable morphology remains challenging. Herein, seven poly(fluorene alkylene) membranes, including random and block-structured membranes with different quaternary ammonium (QA) group distributions on the side chains, with the same ion-exchange capacity (IEC) were designed via superacid-catalyzed polymerization. The properties of the as-synthesized membranes were characterized, and the water-transport mechanism has been discussed in relation to the morphology of the membranes. The formed bicontinuous phase structure based on block biphenyl units possessed multidirectional ion channels and distinct ion clusters favorable to water molecule movement. The conductivity of the optimized membrane with a block biphenyl structure reached 208 mS cm–1 at 80 °C, and the peak power density of an H2/O2 fuel cell based on the as-prepared membrane was 0.92 W cm–2. The reported approach is effective in balancing the content of free and bound water within the membrane, generating maximum hydroxide mobility and water transport suitable for high-performance AEM fuel cells. This study highlights the significance of regulating the block structure and adjusting the segment distribution in AEMs to tune their morphologies and provides an innovative design approach for constructing high-performance AEMs.
研究领域:
材料科学
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能源化学
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DOI
高影响因子
RSC Advances
·
2023
·Vol. 13
·期 35
·24181-24190
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IF 3.9
Liandong Ye,Min Liu,Xiao Wang,Zhihong Yu,Zhihao Huang,Nianchen Zhou,Zhengbiao Zhang,Xiulin Zhu
Sequences can have a dramatic impact on the unique properties and self-assembly in natural macromolecules, which has received increasing interest. Herein, we report a series of discrete amphiphilic co-oligomers with the same composition but different building blocks in a semirigid backbone. These sequence-defined oligomers possess two primary amine groups on the side chain of the azobenzene building block, and hence, they become amphipathic due to quaternization of the amine groups when protonated in acidic aqueous solution. These oligomer isomers assembled into different nanoparticles, including nanofibers, hollow vesicles and spherical micellar complexes, in a THF/water/HCl mixture under the same conditions. UV-vis absorption spectra, differential scanning calorimetry (DSC) and X-ray scattering (XRD) experiments combined with theoretical calculations reveal that the sequence-controlled co-oligomers induce different molecular packing conformations and arrangement modes of building blocks in self-assembly. Furthermore, these self-assembled nanoparticles demonstrate photoresponsive morphological transformation and fluorescence emission under UV light irradiation due to trans-to-cis photoisomerization of azobenzene. This work demonstrates that customizing functional nanoparticles can be achieved by controlling the sequence structure in synthetic co-oligomers.
研究领域:
材料科学
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纳米技术
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高分子化学
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物理化学
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DOI
PubMed
高影响因子
ACS Applied Nano Materials
·
2023
·
IF 5.9
Ya Lu,Zhuanfang Bi,Guangyi Shang
Fluorene, as one of the important organic compounds widely used in the field of medicine and photoelectric materials, could damage human health even if it is extremely low in the environment. The development of ultrasensitive and easy-recyclable surface-enhanced Raman scattering (SERS) detection of trace fluorene is highly desired. In this work, a nanocomposite of Ag nanoparticles (Ag NPs) and porous g-C3N4 is synthesized by a facile method. The advantageous features of the as-prepared nanocomposite include a high SERS sensitivity due to the plasmonic effect of the Ag NPs, excellent recyclability due to the self-cleaning ability originating from the photocatalytic degradation of porous g-C3N4 under visible light irradiation, and good adsorption due to the large specific surface area of porous g-C3N4. The experimental results show that an ultralow detection limit of 1.35 × 10–13 M for R6G can be achieved. Especially, the nanocomposite exhibits excellent performance for the detection of fluorene with the detection limit of 3.11 × 10–11 M and multidetection of at least 13 cycles. The present research provides a nanocomposite with excellent synergistic activity of plasmonic enhancement and photocatalytic degradation for the recyclable SERS detection of trace fluorene.
研究领域:
材料科学
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环境科学
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分析化学
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DOI
高影响因子
ACS Applied Polymer Materials
·
2025
·
IF 4.7
Shuo Wang,Pei Wang,Yunlong Sun,Jiyong Zhao,Zhipeng Wang
The rapid advancement of high-frequency communication networks has imposed more rigorous demands on the overall characteristics of dielectric materials. Poly(aryl ether ketone)s (PAEKs) are good candidate materials for applications in microelectronic devices due to their excellent thermal stability, mechanical properties, and chemical stability. In this work, we endeavored to incorporate large-volume fluorene structures into fluoro-PAEKs, employing strategies to enhance the polymer free volume and reduce polarizations in order to decrease the values of Dk and Df at high frequency. Therefore, a series of poly(ether ketone) (PEK-pOCFBPF-X) copolymers were designed and synthesized through nucleophilic polymerization using 4,4-difluorobenzophenone (DFK), phenolphthalein anilide-containing trifluoromethoxy groups (PPPBP-pOCF3), and a structurally ordered bisphenol fluorene (BPF) as the monomers. The results demonstrate that the introduction of BPF into fluoro-PAEKs resin leads to a low dielectric constant (2.713–2.782@10 GHz) and dielectric loss (0.00597–0.00825@10 GHz), as well as exceptional thermal properties (Tg = 232–240 °C, Td5% = 518–536 °C). Moreover, the copolymer exhibits high mechanical strength (tensile strength ≥ 81 MPa), minimal water absorption (≤0.0063), and excellent solubility. The incorporation of trifluoromethoxy and fluorenyl groups into copolymers significantly enhances the free volume fraction (5.5%–5.8%), resulting in a lower density and reduction in the dielectric constant. Simultaneously, by introducing C–F bonds with lower polarizability, the overall polarizability of the polymer is effectively diminished. These fluoro-PAEKs films, which exhibit superior thermal stability and a low dielectric constant, have great potential for applications in the high-performance flexible electronic packaging field and communication usage.
研究领域:
材料科学
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电子工程
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产品关联
DOI
高影响因子
RENEWABLE ENERGY
·
2025
·
IF 9.1
Fenglong Chen,Lingxin Meng,Jingmei Xu,Hongqi Liang,Kuirong Feng,Tian Lan,Jiayin Wang,Qingyuan Shi
The sulfonated poly(arylene ether ketone sulfone)s which contains fluorenyl groups (F-SPAEKS) as proton exchange membranes (PEMs) matrix is prepared. UiO-66-NH 2 -PO 4 H 2 (PUIN) is synthesized based on UiO-66-NH 2 as a template for immobilizing phosphate groups onto MOFs by chemical bonding via Schiff base reaction. UiO-66-SO 3 H-PO 4 H 2 (SPUIN) is prepared via ring-opening of 1,3-propanesulfonolactone, where -SO 3 H is introduced at the -NH 2 site of PUIN. The hybridized PEMs (FSSPU-X) are obtained by adding SPUIN as fillers into F-SPAEKS polymers. From all prepared PEMs, FSSPU-7 which means the weight ratio of SPUIN is 7% shows the best performances in comprehensive aspects. The H + conductivity of FSSPU-7 is enhanced to 247.38 mS cm -1 and the peak power density is 1140 mW cm -2 with 0.48 mg cm -2 Pt/C loading. At the same time, the swelling ratio of FSSPU-7 remains below 17%. Besides, FSSPU-7 has a maximum tensile strength up to 32.37 MPa. And the proton conductivity of FSSPU-7 is consistently maintained at about 240 mS cm -1 after 144 hours of long-term stability test. Therefore, the preparation of PEMs with a high level of performance is expected by introducing phosphoric acid and sulfonic acid bi-functionalized UiO-66 into F-SPAEKS.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2019
·
IF 4.084
Bin Shen,Hongting Pu
Anion exchange membranes with high ionic conductivity and dimensional stability attract a lot of research interests. In present study, a series of fluorene-containing poly(arylene ether sulfone)s containing imidazolium on the flexible long side-chain are synthesized via copolycondensation, Friedel-Crafts reaction, ketone reduction, and Menshutkin reaction sequentially. The membranes used for characterization and membrane electrode assembly are obtained by solution casting and ion exchange thereafter. The morphology of the membranes is studied via transmission electron microscopy , and the microphase separation is observed. The long side-chain structure is responsible for the distinct hydrophilic-hydrophobic microphase separation, which facilitates the transport of hydroxide ions in the membranes. The incorporation of imidazolium on the flexible long side-chain is favorable for the ionic aggregation and transport in the membranes. The resulted membranes exhibit high hydroxide conductivities in the range of 48.5–83.1 mS cm −1 at 80 °C. All these membranes show good dimensional stability and thermal stability. The single cell performance shows a power density of 102.3 mW cm −2 at 60 °C using membrane electrode assembly based-on one of the synthesized polymers.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
POLYMER INTERNATIONAL
·
2020
·Vol. 70
·期 3
·282-287
·
IF 2.574
Jiaxin Wei,Yingshuang Shang,Da Xu,Zhaoyang Wang,Zilong Jiang,Yanwei Gao,Haibo Zhang
A series of novel poly(ether ketone) copolymers with different contents of fluorene groups were synthesized. The effects of fluorene group content on the thermal and mechanical properties of poly(ether ketone) copolymers were investigated. The introduction of a low content of fluorene groups can lead to an increase in glass transition temperature, thermal stability and heat deflection temperature. Among them, the heat deflection temperature of 10% fluorene-containing poly(ether ketone) copolymers (PEK-FD10) increases from 178 °C (pure poly(ether ketone)) to 196 °C, which means that the material has a higher heat resistance rating. Compared with poly(ether ketone)s, these copolymers have excellent mechanical properties. When the content of fluorene groups is only 2% (PEK-FD2), the strength is significantly improved. And the flexural strength of PEK-FD2 is 149.3 MPa, which is 12% higher than that of poly(ether ketone). It is worth noting that the fracture toughness and impact toughness are also increased significantly. The strain at break of PEK-FD2 is up to 88% and the impact toughness of PEK-FD2 is 54.6 J m −1 . This suggests that the introduction of minute contents of fluorene groups can simultaneously increase the strength and toughness. © 2020 Society of Industrial Chemistry
研究领域:
材料科学
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高分子化学
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DOI
高影响因子
Polymers
·
2018
·Vol. 10
·期 4
·450
·
IF 2.935
Jianzhong Xu,Qi Ji,Lingqian Kong,Hongmei Du,Xiuping Ju,Jinsheng Zhao
A series of π-conjugated polymers containing alternating benzoselenadiazole (BSe)-bi(thiophene derivative)-carbazole or benzoththiadiazole (BSe)-bi(thiophene derivative)-fluorene units were designed and synthesized. Thiophene derivatives, namely 3-hexylthiophene, 3,4-bihexyloxythiophene, and 3,4-bioctyloxythiophene, were used as the π-bridges of the polymers. The polymers were characterized in detail in terms of their thermal stabilities, cyclic voltammograms, UV-Vis absorption, spectroelectrochemistry, dynamic switching property and so forth. The alkoxy thiophene π-bridged polymers have lower onset oxidation potentials and bandgaps than that of their corresponding alkyl thiophene π-bridged polymers. The selection of the donor units between the carbazole and the fluorene units has nearly no effect on the bandgaps and colors as well as the onset oxidation potentials of the polymers. The increase in the length of the side alkyl chains on the thiophene ring caused a slight increase in the polymer bandgap, which may be caused by the space hindrance effect. The dynamic switching abilities of the polymers were obtained by the chronoabsorptometry method, and the results also suggested that the alkoxy thiophene-containing polymers (as π-bridges) have higher contrast ratios than the corresponding alkyl thiophene-containing polymers. Furthermore, the increase in the length of the side alkyl chain might have a detrimental effect on the optical contrast ratios of the polymers.Keywords:benzoselenadiazole;carbazole;fluorene;conjugated polymer;electrochromic;solution processable
研究领域:
材料科学
·
化学
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产品关联
DOI
PubMed
高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
·
2017
·
IF 5.401
Shi Zhou,Peng Guo,Jinlian Li,Lingren Meng,Hongfu Gao,Xing Yuan,Dongmei Wu
Fluorene was one of the priority controlled polycyclic aromatic hydrocarbons (PAHs) and distributed abundantly in the environment, which has a great harmful on human body. It was very important to detect the cytotoxicity of fluorene with a rapid and accurate method. In this present work, a simple and ultrasensitive electrochemical biosensor was developed by electrodeposition of reduced graphene oxide quantum dots (RGOQDs) on glassy carbon electrode (GCE) for the first time. The electrochemical behaviors of uric acid (UA), xanthine (X) and guanine (G) were studied on RGOQDs/GCE by differential pulse voltammetry (DPV) with a limit of detection of 0.024 μM, respectively. Then the electrochemical biosensor was used to evaluate the cytotoxicity of fluorene for MCF-7 cells based on the variation of G/X in MCF-7 cells solution. The result showed that fluorene exposed to MCF-7 cells at the concentration range of 0–0.05 mM could promote cell proliferation, the concentration above 0.05 mM exhibited inhibitory effect, which was verified by methyl-thiazolyl-tetrazolium (MTT) assay. The electrochemical biosensor based on RGOQDs/GCE could be used not only for evaluation the cytotoxicity of PAHs, but also for detection the physiological process related to intracellular purine nucleotide metabolism.
研究领域:
生物医学工程
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环境科学
·
毒理学
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产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2020
·
IF 5.774
Lei Hou,Zhe Wang,Zhaoyu Chen,Wenbo Chen,Cancan Yang
PIM-1 and poly(arylene fluorene ether ketone) (Am-PAFEK) were synthesized by polycondensation . Their structures were characterized by 1 H NMR and FT-IR spectral analyses. A series of flexible and transparent blend membranes were prepared by solution blending with different ratios of PIM-1 and Am-PAFEK. DSC and SEM analyses showed good compatibility between them. PIM-1 and Am-PAFEK in the blend membrane perform their respective functions. The former provides excellent permeability; the latter provides high selectivity for CO 2 . Addition of 20% Am-PAFEK into the blend membrane increased the gas separation selectivity of CO 2 /CH 4 and CO 2 /N 2 by 75% and 65%, respectively. The optimum separation performance was achieved with blend membrane with a CO 2 permeability of 752.4 Barrer and a CO 2 /N 2 selectivity ratio of 26.7, extremely close to the Robeson upper bound (2008). After 140-days aging test, the blend membranes still maintained above 70% CO 2 permeability, indicating that it has good antiaging properties. Consequently, the new type of membranes have great potential in industrial applications.
研究领域:
材料科学
·
环境科学
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产品关联
DOI
高影响因子
SYNTHETIC METALS
·
2018
·
IF 2.526
Yaxin Zhang,Fuhan Liu,Yanjun Hou,Haijun Niu
Here, we synthesized four kinds of monomers of 3,6-dibromo-(N-phenyl)carbazole with different substituent group, DCB, DDC, DNC and DTC, respectively, and used 4-(3-bromo-9H-carbazol-9-yl)benzaldehyde to react with triphenylamine (TPA) unit and hydrazine hydrate unit, respectively, to obtain the other two monomers, BCB-TPA and BCB-HH. Six novel polymers coded as PDCB-DF, PDDC-DF, PDNC-DF, PDCB-DTC-DF, PBCB-TPA-DF and PBCB-HH-DF, were synthesized by Suzuki reactions of 2,2'-(9,9-dioctyl-9H-fluorene-2,7-diyl)bis(1,3,2-dioxaborinane) with the six kinds of monomers and their electrochemical and spectroelectrochemical properties were investigated. The polymers showed good solubility and film-forming ability. Flexible or robust films of them could be readily obtained via solution-casting. These polymers showed the onset temperatures in the range of 300–470 °C when the 10% weight loss of polymers. The polymer films showed high coloration efficiency (CE) (196-376 cm 2 ·C −1 ) and electrochromic stability. These properties illustrate that the polymers have great application prospect as electrochromic materials.
研究领域:
材料科学
·
电化学
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产品关联
DOI
高影响因子
POLYMER
·
2025
·
IF 4.5
Junji Wei,Zeyue Zhang,Zexing Zhang,Runlin Lu,Jinbiao Pang,Shifeng Yuan,Liang Fang,Li Duan,Jian Liu
For decades, high-performance epoxy resins have been pivotal in advancing high-temperature electronic materials. Conventional epoxy resins tend to soften and deform under high-temperature conditions, which compromises their structural stability and fails to meet the stringent thermal reliability requirements of high-temperature processes and equipment. Regarding this, this study presented two new kinds of fluorene-based epoxy monomers bisphenol fluorene epoxy resin (BFEP), isopropyl bisphenol fluorene epoxy resin (IBFEP) and a novel curing agent (1,3-bis(4-aminophenyl) adamantane, AMA) derived from adamantane. The two monomers were cured with two hardeners, 4,4-diaminodiphenyl sulfone (DDS) and AMA, respectively. The DDS cured resins showed high glass transition temperature (BFEP/DDS, 236 °C; IBFEP/DDS, 209 °C), excellent storage modulus, good thermal stability ( T d5% >395 °C) and dimensional stability, low water absorption and good adhesion. However, the dielectric constant (κ) of those two resins were relatively high, e.g. 4.6 was for BFEP/DDS, 4.23 was for IBFEP/DDS at 10 MHz. Compared with DDS system, both resins exhibited a lower glass transition temperature ( T g ) after cured by AMA. However, the latters also possessed a notably high storage modulus at room temperature (RT) (BFEP/AMA, 4420 MPa; IBFEP/AMA, 4630 MPa), lower dielectric constant (BFEP/AMA, 4.05; IBFEP/AMA, 3.74 at 10 MHz), better adhesion and thermal conductivity. In summary, the two kinds of fluorene-based epoxy resins cured with different curing agents exhibited different performance characteristics. The performance of AMA cured epoxy resin exhibited more balanced behaviors due to its excellent rigid and hollow structure, which could be suitable for high- T g PCB substrate materials.
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DOI
高影响因子
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