LANGMUIR
·
2024
·
IF 3.7
Zihao Meng,Ying Wang,Yanlong Luo,Zhenyang Luo,Linling Li,Ye Sha
Using a “core-first” approach with atom transfer radical polymerization, fluorescent center-functional star polymers of equivalent molecular weight but with varying numbers of arms (di-, tri-, and tetra-arm) were prepared. The sensitivity of fluorescence, combined with a dye-labeling technique introducing a fluorescent donor (carbazole) and an acceptor (anthracene) at the center of poly(methyl methacrylate) (PMMA) chains, enabled the application of time-resolved fluorescence resonance energy transfer to obtain quantitative insights into the conformation of the star polymer chains in the film state. When the results of star-branched polymers were compared with those of linear polymers of identical type and molecular weight, the impact of branching on polymer behavior was isolated for examination. Although the star topology does not alter the average intercoil distance, it affects the distance dispersity. Star polymers with higher arm numbers display decreased dispersity from distance due to reduced intermolecular aggregation at their geometric centers. This study presents the first spectroscopic evidence regarding the distribution of geometric centers in star polymers, offering a physical understanding of chain interpenetration and entanglement within star polymers.
研究领域:
高分子化学
·
材料科学
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DOI
PubMed
高影响因子
EUROPEAN POLYMER JOURNAL
·
2018
·
IF 3.741
Shan Zhang,Yinglai Hou,Heng Chen,Zijun Liao,Jianxin Chen,Ben B. Xu,Jie Kong
In this contribution, the reduction-responsive star copolymers with long-chain hyperbranched poly(ε-caprolactone) (PCL) (HyperMacs) core and disulfide bonds were synthesized via Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction. The HyperMacs core was constructed from disulfide-containing AB 2 -type PCL macromonomers, which possesses length-adjustable chain segments between branching points, large cavities, low degree of crystallinity, and reduction-responsivity. After grafted with poly(ethylene glycol), the reduction-responsive star copolymers can self-assemble into micelles in aqueous solution. The obtained micelles exhibited much lower critical micelle concentration (CMC) than their linear analogues. The reduction-responsivity from disulfide bonds makes them a promising carrier candidate for trigger release of anticancer drugs. The in vitro release results confirmed that their doxorubicin (DOX)-loaded micelles exhibited desirable reduction-triggered release performance. The cellular proliferation inhibition against HepG2 cells demonstrated that the DOX-loaded micelles showed a comparable anticancer activity with free DOX. Therefore, it can be expected that the reduction-sensitive micelles may serve as smart vehicles for intracellular delivery of anti-cancer drugs in tumour therapy.
研究领域:
聚合物化学
·
纳米医学
·
药物递送系统
·
癌症治疗
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DOI
高影响因子
MACROMOLECULES
·
2026
·
IF 5.7
Jin Zhang,Xiaoou Li,Yu Zhang,Xin Wang,Miaomiao Han,Yadong Liu,Shengxiang Ji
Directed self-assembly (DSA) of block copolymers in combination with 193 nm immersion lithography (193i) is one of the potential solutions for sub-10 nm patterning. Here we report the synthesis and DSA of a high-χ miktoarm star block copolymer, polystyrene-(poly(methyl acrylate)2 (PS–PMA2), for sub-10 nm nanolithography. Compared with diblock PS-b-PMA, PS–PMA2 has a higher effective χ value (0.095@150 °C) and a smaller period with the same molecular weights. The smallest achievable period (L0) was 12.8 nm for PS–PMA2, while a perpendicular orientation of lamellar domains was obtained in PS–PMA2 films with L0 down to 14.1 nm. DSA of PS–PMA2 with 5× density multiplication was successfully achieved on chemical patterns with the pattern period (LS) of 80–90 nm defined by 193i with a feature size down to 8 nm. In addition, DSA of PS-b-PMA was also demonstrated on 193i-defined patterns with a feature size of 9 nm.
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高影响因子
JOURNAL OF ELECTRONIC MATERIALS
·
2019
·Vol. 48
·期 8
·4895-4901
·
IF 1.676
Zhang Weiguo,Chang Shuaishuai,Yao Suwei,Wang Hongzhi
Submicron star-like ZnO (ZnO SZ) was synthesized via a facile hydrothermal method, and a series of composite photoanode materials with different ZnO SZ concentrations in the range from 0 wt.% to 0.20 wt.% were synthesized by a mechanical mixing method. The as-prepared samples were characterized by x-ray diffraction analysis, scanning electron microscopy, ultraviolet–visible (UV–Vis) absorption spectroscopy, etc. The results clearly showed that the mean diameter of the ZnO SZ was approximately 300 nm while its length was in the micrometer range, and the ZnO SZ was embedded homogeneously into the ZnO nanoparticle photoanode. Although UV–Vis spectral analysis revealed that increasing the ZnO SZ content decreased the dye adsorption density of the composite photoanode, the photocurrent density–voltage ( J – V ) characteristic indicated that dye-sensitized solar cells (DSSCs) using the ZnO SZ/ZnO composite photoelectrode exhibited significantly improved photovoltaic performance compared with those using pure ZnO nanoparticles. Electrochemical measurements revealed that DSSCs using 0.10 wt.% ZnO SZ showed improved efficiency of light energy conversion of 1.38%, being 43.75% higher than when using pure ZnO. All these results prove that incorporation of ZnO SZ into the ZnO nanoparticle photoelectrode represents a highly effective method for improving the photovoltaic properties of DSSCs.
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高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2019
·
IF 4.175
Man Zhou,Jingwen Chen,Yakang Zhang,Mengting Jiang,Song Xu,Qian Liang,Zhongyu Li
As a typical perovskite-type metal oxide , SrTiO 3 has emerged as prospective candidate for many fields. However, the synthesis of SrTiO 3 with controlled morphology, high surface area, and enhanced photocatalytic activity are still lacking. Herein, a series of porous SrTiO 3 with well-controlled morphologies including assembled nanoparticles (ANPs), golf-like particles (GLPs), star-like microspheres (SLMs), urchin-like microspheres (ULMs), and flower-like microspheres (FLMs) were successfully prepared via an ethylene glycol-water mixed solvothermal route. The ratio of V EG /V H2O play an important role in the shape-evolution during the solvothermal reaction. A comparative study of photocatalytic H 2 production and photodegradation was performed, and a possible photocatalysis mechanism of SrTiO 3 has been proposed. Significantly, the ULMs and FLMs photocatalysts of SrTiO 3 with optimized low Pt loading amount (0.075 wt %) exhibited outstanding H 2 production rates (8.21 and 7.29 mmol g −1 h −1 ) due to its unique structure of high-surface area and defect-rich surface. The facile and shape-controlled synthesis of varied SrTiO 3 structures is believed to be useful for the design and application of perovskite .
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高影响因子
ACS Applied Materials & Interfaces
·
2019
·
IF 8.456
Pingping Chen,Xu Liu,Shi Wang,Qinghui Zeng,Zhinan Wang,Zengxi Li,Liaoyun Zhang
The original poly(ethylene oxide)-based polymer electrolytes normally show low ionic conductivity and inferior mechanical property, which greatly restrict their practical application in all-solid-state lithium-ion batteries (LIBs). In this work, a hyperbranched star polymer with poly(ethylene glycol) methyl ether methacrylate flexible chain segments is embedded into a three-dimensional (3D) interpenetrating cross-linking network created by the rapid one-step UV-derived photopolymerization of the cross-linker (ethoxylated trimethylolpropane triacrylate) in the presence of lithium salt. The rigid 3D network framework provides the polymer electrolyte with not only enhanced mechanical behavior, including film-forming and dendrite-inhibiting capabilities, but also nanoconfinement effects, which can speed up polymer chain segmental dynamics and reduce the crystallinity of the polymer. Depending on this unique rigid–flexible coupling network, the prepared solid polymer electrolyte shows enhanced ionic conductivity (6.8 × 10–5 S cm–1 at 50 °C), widened electrochemical stability window (5.1 V vs Li/Li+), and enough mechanical stability to suppress the growth of uneven Li dendrite (the Li symmetrical cells can operate steadily at both current densities of 0.05 and 0.1 mA cm–2 for 1000 h). Moreover, the assembled LiFePO4//Li cell also exhibited good cycle performance at 50 °C, making the hyperbranched star polymer electrolyte with a nanoconfined cross-linking structure to have potential application in high-safety and high-performance LIBs.
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产品关联
DOI
PubMed
高影响因子
REACTIVE & FUNCTIONAL POLYMERS
·
2015
·
IF 2.515
Chong Zhang,Lijuan Chen,Lin Tan,Xiajun Zheng,Yanmei Wang
In this study, a set of well-defined multiarm star copolymers , hyperbranched poly(ethylenimine)-graft-poly(ethylene glycol) (bPEI- g -PEG) with different PEG grafting ratios were synthesized. The star PEG-based coatings were then prepared by immobilizing the corresponding copolymers onto poly(dopamine) (PDA)-coated substrates. The chemical composition , hydrophilicity , surface topography , and thickness of the coatings were studied by X-ray photoelectron spectroscopy (XPS), water contact angle (WCA), atomic force microscopy (AFM), and variable angle spectroscopic ellipsometry (VASE), respectively. Furthermore, the surface PEG chain density of star PEG-based coating was evaluated quantitatively and compared with that of linear PEG-based coating. Our results showed that the amount of proteins (albumin from bovine serum, fibrinogen, and lysozyme) adsorbed on the star PEG-based coating as measured by surface plasmon resonance (SPR) was found to be dependent on the surface PEG chain density, which was controlled by the polymer incubation concentrations and PEG grafting ratios. Generally, the star-shaped PEG gave the surface with higher PEG chain density than linear ones and the amount of adsorbed proteins decreased with increasing surface PEG chain density. At last, the star PEG-based coating was successfully applied into the capillary inner surface for protein separation by capillary electrophoresis (CE).
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高影响因子
RSC Advances
·
2014
·Vol. 4
·期 97
·54268-54281
·
IF 3.708
Yinwen Li,Huilong Guo,Jian Zheng,Jianqun Gan,Yan Zhang,Xiaoxiao Guan,Kun Wu,Mangeng Lu
Novel macromolecular star polymers with triazole and cyclodextrin (CD) segments as branch points and poly(oligo(ethylene glycol)methacrylate) (POEGMAs) as dense hydrophilic branches were synthesized via a combination of azide–alkyne click chemistry and atom transfer radical polymerization (ATRP). Firstly, a tetrafunctional linking agent (PETP) was prepared by the reaction of pentaerythritol (PE) and propargyl bromide, and then a four arm β-CD terminated star polymer (PE-CD) was obtained through the click chemistry reaction. Finally, thermally-responsive star polymers (PE-CD–POEGMAs) with PE as the central core, triazole and CD segments as branch points, and POEGMAs as side branches were synthesized by the ATRP of MEO2MA and OEGMA using PE-CD terminated with bromines as macroinitiators. A study on the thermoresponsivity and morphology of PE-CD–POEGMAs indicated that polymeric nano-aggregates existed as multimolecular micelles and behaved with tunable thermosensitivity, which were driven by the strong hydrophobic–hydrophilic interactions in the inner core and outer shell. The encapsulation capacities towards multi-guest molecules were investigated and the results indicated that water soluble guests could be encapsulated by PE-CD–POEGMAs, and the guest encapsulation capacities were derived from the special star molecular structure properties of PE-CD–POEGMAs and the synergistic encapsulation phenomenon of different guest molecules. This unique amphiphilic star polymer illustrated the potential applications in supramolecular science, drug delivery and other nanotechnology applications.
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高影响因子
REACTIVE & FUNCTIONAL POLYMERS
·
2024
·
IF 4.5
Chong Wang,Pei-Yi Liu,Ze-Zhong Lin,Yu Chen,Hai-Chao Li
Numerous plasticizers have been developed to acquire the traditional soft poly(vinyl chloride) (PVC) that is characteristic of a high elongation at break, but a low modulus of <70 MPa. Special highly-stretchable PVCs with high modulus (>70 MPa) are highly desirable for widening the application fields of PVC materials. Herein, a series of star copolymers with hyperbranched polyethylenimine (PEI) as core and poly(ε-caprolactone) (PCL) as shell (PEI-PCL) were utilized as plasticizers to prepare functional highly-stretchable semi-rigid plasticized PVC materials. Under the 0.5 weight ratio of PEI-PCL to PVC, the obtained plasticized PVCs showed the highest modulus of around 392 MPa under the assuring of >400% elongation at break, which was nearly four-fold of the most rigid plasticized PVC materials ever-reported. Through the further DSC and FTIR characterizations and the comparison with linear PCL plasticizers, the reason for so rigidity was ascribed as that the guest-encapsulation capability of PEI-PCLs led to the physical crosslinking of PVC chains by the amidated PEI core through the dense hydrogen-bonds. Furthermore, PEI-PCLs could disperse hydrophilic dyes homogeneously into PVC matrix, resulting in colorful or photoluminescent PVC materials.
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DOI
高影响因子
FASEB JOURNAL
·
2024
·Vol. 38
·期 13
·e23781
·
IF 4.4
Wenfang Lai,Siying Huang,Junjie Liu,Binbin Zhou,Zhengshuang Yu,John Brown,Guizhu Hong
Reactive astrocytes are important pathophysiologically and synthesize neurosteroids. We observed that LPS increased immunoreactive TLR4 and key steroidogenic enzymes in cortical astrocytes of rats and investigated whether corticosteroids are produced and mediate astrocytic TLR4-dependent innate immune responses. We found that LPS increased steroidogenic acute regulatory protein (StAR) and StAR-dependent aldosterone production in purified astrocytes. Both increases were blocked by the TLR4 antagonist TAK242. LPS also increased 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) and corticosterone production, and both were prevented by TAK242 and by siRNAs against 11β-HSD1, StAR, or aldosterone synthase (CYP11B2). Knockdown of 11β-HSD1, StAR, or CYP11B2 or blocking either mineralocorticoid receptors (MR) or glucocorticoid receptors (GR) prevented dephosphorylation of p-Ser 9 GSK-3β, activation of NF-κB, and the GSK-3β-dependent increases of C3, IL-1β, and TNF-α caused by LPS. Exogenous aldosterone mimicked the MR- and GSK-3β-dependent pro-inflammatory effects of LPS in astrocytes, but corticosterone did not. Supernatants from astrocytes treated with LPS reduced MAP2 and viability of cultured neurons except when astrocytic StAR or MR was inhibited. In adrenalectomized rats, intracerebroventricular injection of LPS increased astrocytic TLR4, StAR, CYP11B2, and 11β-HSD1, NF-κB, C3 and IL-1β, decreased astrocytic p-Ser 9 GSK-3β in the cortex and was neurotoxic, except when spironolactone was co-injected, consistent with the in vitro results. LPS also activated NF-κB in some NeuN + and CD11b + cells in the cortex, and these effects were prevented by spironolactone. We conclude that intracrine aldosterone may be involved in the TLR4-dependent innate immune responses of astrocytes and can trigger paracrine effects by activating astrocytic MR/GSK-3β/NF-κB signaling.
研究领域:
神经科学
·
免疫学
·
药理学
·
分子生物学
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DOI
PubMed
高影响因子
POLYMER BULLETIN
·
2017
·Vol. 75
·期 7
·2917-2931
·
IF 1.43
Ding Amin,Teng Lijing,Zhou Yifeng,Chen Pengpeng,Nie Wangyan
The star-shaped poly( l -lactide) (s-PLLA) was synthesized via ring-opening polymerization of l -lactide, with xylitol as a multifunctional initiator and stannous octoate as a catalyst. The structures of s-PLLA were characterized by 1 H NMR spectroscopy, while the molecular weight ( M
w ) and polydispersity index were determined by gel permeation chromatography. Bovine serum albumin (BSA) loaded s-PLLA microspheres were fabricated by a water–oil–water ( W
1 / O / W
2 ) double-emulsion solvent evaporation method. The morphology, drug encapsulation efficiency (EE), and in vitro release behavior of the prepared microspheres were studied in detail. Results indicated that the average diameters of s-PLLA microspheres could be controlled between 7 and 15 µm by varying the s-PLLA’s concentration or M
w , and the drug encapsulation efficiency of BSA-loaded microspheres were 10–42%. The in vitro study shows that the BSA-loaded microspheres prepared by high molecular weight s-PLLA had a slow cumulative release behavior in phosphate buffer saline (PBS, pH 7.4) and the release process followed the Baker–Lonsdale equation. Present work supposes that the synthesized s-PLLA is a good candidate for drug delivery.
研究领域:
生物材料学
·
药剂学
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DOI
高影响因子
Science China-Chemistry
·
2015
·Vol. 58
·期 2
·357-363
·
IF 1.695
Zhou Yuanhang,Chen Weichao,Du Zhengkun,Zhu Dangqiang,Ouyang Dan,Han Liangliang,Yang Renqiang
A new star-shaped small molecule named TCNR3TTPA, with a triphenylamine (TPA) unit as the central building block and 2-(1,1-dicyanomethylene)-3-octyl rhodanine (CNR) as the end-capped group, has been designed and synthesized. TCNR3TTPA showed a deep highest occupied molecular orbital (HOMO) energy level (−5.60 eV) and broad absorption. The solution-processed bulk heterojunction (BHJ) solar cells based on TCNR3TTPA:PC 61 BM (1:1, w / w ) exhibited a high open-circuit voltage ( V
oc ) of 0.99 V, a short-circuit current density ( J
sc ) of 5.76 mA/cm 2 , and a power conversion efficiency (PCE) of 2.50% under the illumination of AM 1.5 G, 100 mW/cm 2 . The high V
oc is ascribed to the strong electron-with- drawing ability of the end-capped 2-(1,1-dicyanomethylene)-3-octyl rhodanine group. These results demonstrated that the V
oc of small-molecule organic solar cells could be increased by introducing a strong electron-withdrawing end-capped block, and that this is an effective strategy to design high-performance small molecules for organic solar cells.
研究领域:
材料科学
·
化学
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DOI
高影响因子
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