Polymer Chemistry
·
2013
·Vol. 4
·期 6
·1921-1931
·
IF 5.231
Wei Zhou,Weijun Yu,Zesheng An
Core cross-linked star (CCS) polymers of poly(N,N-dimethylacrylamide) (PDMA) were prepared and explored as macromolecular chain transfer agents (Macro-CTAs) in the emulsion polymerization of styrene. The mass ratio of styrene : CCS and the solid content were systematically varied to elucidate their effect on the size and morphology of the particles. Control experiments using linear PDMA as a Macro-CTA were also performed in order to understand the mechanistic difference in CCS-mediated emulsion polymerization. While a two-phase process was typical of emulsion polymerization using linear Macro-CTAs, the CCS polymers functioned as “seeds” for the emulsion polymerization of styrene and exhibited a much higher polymerization rate. Significant clustering of spherical particles was observed when the mass ratio of styrene : CCS was increased while maintaining the solid content. On the other hand, linear and branched fibers were observed when the solid content was increased while maintaining the mass ratio of styrene : CCS. This morphology transformation is unique to CCS-mediated emulsion polymerization, and a protrusion mechanism caused by the cross-links in the core of the CCS was proposed to account for the aggregation of spherical particles into clusters or fibers.
研究领域:
材料科学
·
高分子化学
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DOI
高影响因子
SYNTHETIC METALS
·
2020
·
IF 3.286
Song Liu,Zhen-jie Huang,Feng Li,Wei-jing Zhang,Chun-rong Zhu,Cheng-bin Gong,Jun-fei Long,Qian Tang
In this study, a series of novel star-shaped monosubstituted 2,6-diphenyl-4,4′-bipyridinium salts with various alkyl, alkenyl, and aryl groups were designed and synthesized, and their electrochemical, electro-optical, and electrochromic properties were investigated. The electrochromic properties such as different colored states (sky blue versus purple), reasonable contrast, coloration efficiency, and, in particular, the switching stabilities of electrochromic devices based on star-shaped monosubstituted 2,6-diphenyl-4,4′-bipyridinium salts were better than those of devices based on linear monosubstituted pyridinium salts. All the compounds with alkyl, alkenyl, and aryl groups showed good switching stability and the change in the optical contrast after 1000 cycles was small (<5%). However, N-substituents significantly affected the switching stability of electrochromic devices based on linear monosubstituted 4,4′-bipyridine derivatives.
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高影响因子
COLLOIDS AND SURFACES B-BIOINTERFACES
·
2017
·
IF 3.887
Ruitao Cha,Juanjuan Li,Yang Liu,Yifan Zhang,Qian Xie,Mingming Zhang
Fe 3 O 4 nanoparticles with ultrasmall sizes show good T 1 or T 1 + T 2 contrast abilities, and have attracted considerable interest in the field of magnetic resonance imaging (MRI) contrast agents. For effective biomedical applications, the colloidal stability and biocompatibility of the Fe 3 O 4 nanoparticles need to be improved without reducing MRI relaxivity. In this paper, star polymers were used as coating materials to modify Fe 3 O 4 nanoparticles in view of their dense molecular architecture with moderate flexibility. The star polymer was composed of a β-cyclodextrin (β-CD) core and poly(2-(dimethylamino) ethyl methacrylate) (PDMAEMA) arms. Meanwhile, reduced glutathione (GSH), as a model drug, was also associated with the star polymer. Thus, a new platform for simultaneous diagnosis and treatment was achieved. Compared to the Fe 3 O 4 nanoparticles coated with linear polymers, the Fe 3 O 4 nanoparticles coated with star polymers (Fe 3 O 4 @GCP) possessed higher GSH association capacity and better stability in serum-containing solution. GSH could be released from Fe 3 O 4 @GCP nanoparticles in response to pH value of the solution. Since the sulfhydryl group on GSH is able to combine free radicals, Fe 3 O 4 @GCP nanoparticles exhibited less cytotoxicity compared to the Fe 3 O 4 nanoparticles without including GSH. Furthermore, the nanoparticles could also serve as good T 1 MRI contrast agent, and the MRI relaxivity of Fe 3 O 4 @GCP nanoparticles did not decrease after coated with the star polymer. These results indicate that the precisely designed Fe 3 O 4 @GCP nanoparticles could be used as a versatile promising theranostic nano-platform.
研究领域:
纳米技术
·
材料科学
·
生物医学工程
·
磁共振成像
·
药物递送系统
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DOI
PubMed
高影响因子
CHINESE JOURNAL OF POLYMER SCIENCE
·
2014
·Vol. 33
·期 2
·245-255
·
IF 1.42
Zhang Di,Yin Jun,He Fei,Ge Ni-lin,Wu Zong-quan,Ding Yun-sheng
We report on the preparation of a well-defined star-shaped tricationic ionic liquid possessing three arms of poly(ethylene glycol) functionalized imidazolium rings. Remarkable solubility was found in most of the organic solvents we used. Thermogravimetric analysis (TGA) exhibited excellent thermal stability and two distinct decomposition temperatures were attributed to two kinds of chemical degradation. Differential scanning calorimetry (DSC) was further employed to investigate the thermal phase transitions, that three different signals ( T
g , T
c , and T
m ) were shown upon the second heating process. Moreover, CH 2 Cl 2 solution of the ionic liquid expressed an excitation-wavelength dependent fluorescence response, leading to the facile modulation of photoluminescence behavior. This work represents an example of utilizing molecular design to construct novel ionic liquids and endow further potential to be used in the engineering materials.
研究领域:
材料科学
·
化学工程
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DOI
高影响因子
JOURNAL OF CHROMATOGRAPHY A
·
2017
·
IF 3.981
Qiaochu Zhang,Meiling Qi,Jinliang Wang
This work reports oligothiophene-functionalized truxene-based stationary phases (TTT, TDT and TFT) with a unique star-shaped π-conjugated architecture for gas chromatographic (GC) separations. They exhibited medium polarity and column efficiency of 3340–3760 plates/m determined by naphthalene at 120 °C. Among them, the TTT stationary phase displayed advantageous resolving capability over the TDT and TFT phases for a wide ranging analytes from apolar to polar, particularly for structural and positional isomers, including alcohols, phenols, halogenated and alkylated benzenes and naphthalenes. Moreover, the TTT column exhibited good thermal stability and repeatability with relative standard deviation (RSD) values of 0.02%–0.07% for run-to-run, 0.10%–0.53% for day-to-day and 2.1%–2.9% for column-to-column, respectively. In addition, it was applied for the determination of isomer impurities in real samples, proving its good potential for practical GC analysis.
研究领域:
分析化学
·
材料科学
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DOI
PubMed
高影响因子
IONICS
·
2014
·Vol. 20
·期 9
·1225-1234
·
IF 1.836
Ren Shitong,Zheng Tao,Zhou Qian,Zhang Liaoyun,Li Huayi
Hyperbranched star polymer HBPS-(PPEGMA)
x
was synthesized by atom transfer radical polymerization (ATRP) using hyperbranched polystyrene (HBPS) as macroinitiator and poly(ethylene glycol) methyl ether methacrylate (PEGMA) as monomer. The structure of the prepared hyperbranched star polymer was characterized by 1 H NMR, ATR-FTIR, and GPC. Polymer electrolytes based on HBPS-(PPEGMA)
x
, lithium salt, and/or nano-TiO 2 were prepared. The influences of lithium salt concentration and type, nano-TiO 2 content, and size on ionic conductivity of the obtained polymer electrolytes were investigated. The results showed that the low crystallinity of the prepared polymer electrolyte was caused by the interaction between lithium salt and polymer. The addition of TiO 2 into HBPS-(PPEGMA)
x
/LiTFSI improved the ionic conductivity at low temperature. The prepared composite polymer electrolyte showed the highest ionic conductivity of 9 × 10 −5 S cm −1 at 30 °C when the content of TiO 2 was 15 wt% and the size of TiO 2 was 20 nm.
研究领域:
材料科学
·
电化学
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DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2018
·
IF 3.141
Xiangfei Zheng,Changwei Ji,Jingcheng Liu,Ren Liu,Qidao Mu,Xiaoya Liu
Xanthate-mediated reversible addition–fragmentation chain transfer (RAFT) methodologies have been applicable to preparation of branched or star polymers. In this article, novel star copolymers have been synthesized through xanthate-mediated RAFT polymerization with p-acetoxystyrene and tert-butyl acrylate. Fourier transfer infrared, nuclear magnetic resonance spectra, and gas chromatography analyses indicated that the polymerization was successful between both of the monomers and the star RAFT agent. The intrinsic viscosity and Zimm branching factor (g′) were used to confirm the copolymers’ architecture. The ultraviolet absorbance of the copolymer solutions indicated that the copolymer was suitable for use as a krypton fluoride (KrF) laser photoresist. Moreover, the photolithography performance of the positive-tone chemically amplified photoresist was evaluated. The results indicated that the photosensitive based on the star copolymer was higher than the linear one, and the pattern resolution was around 200 nm at a low exposure energy.
研究领域:
材料科学
·
高分子化学
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产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2023
·
IF 9.9
Qian Ma,Rong Qiang,Yulong Shao,Xiao Yang,Rui Xue,Bowen Chen,Yi Chen,Shijiang Feng
The demand of microwave absorption materials (MAMs) with unique morphologies and electromagnetic (EM) balance has become necessary in recent years. Due to the ease of synthesis and tunable structure, metal–organic frameworks (MOFs) are widely used for this special MAMs. In this study, a new three-dimensional hybrid MOF is proposed that is co-doped with six equally branched star morphologies. The Co-C composite has the same six-branched morphology as that of the precursor. When the EM wave is incident, this special structure makes it easier for the EM wave to enter the material vertically due to the expansion of the incident surface, which is effective in adjusting the transmission path of the electron and the reflection and distribution of the EM wave. Because of the special morphology and magneto-dielectric synergy, the Co-C composite shows a minimum reflection loss ( R Lmin ) of −48.5 dB at 11.0 GHz at an absorption thickness of 3.0 mm, with a microwave absorption bandwidth (EAB) of 6.1 GHz. This research provides a practical guidance for preparing the MAMs of special star structure.
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PubMed
高影响因子
Materials
·
2019
·Vol. 12
·期 10
·1610
·
IF 2.972
Wenzhao Jiang,Jianwei Guo,Weiqiu Wen,Yong-Guang Jia,Sa Liu
Polymeric nano-carriers are considered as promising tools in biomedical applications due to multiple attractive characteristics including their low toxicity, high loading capacity, controlled drug release capabilities, and highly tunable chemical properties. Here, a series of pH-sensitive star-shaped copolymers, Ad-P[(EMA-co-MAA)-b-PPEGMA]4, was prepared via electron transfer atom radical polymerization (ARGETE ATRP) and selective hydrolysis. These star-shaped copolymers can be self-assembled into micelles (Dh= 150–160 nm) and their critical micelle concentrations (CMC) were estimated to be 3.9–5.0 mg/L. The pH-sensitiveness of the micelles was evidenced by transmission electron microscopy (TEM) and dynamic light scattering (DLS). The maximal paclitaxel (PTX) loading efficiency (DLC) and entrapment efficiency (EE) were 18.9% and 36%, respectively. In vitro release studies revealed that about 19% of the PTX released at an acidic condition of pH 1.2 over 70 h, whereas more than 70% was released within the same time interval at pH 6.8. In vitro cytotoxicity suggested that the low cytotoxicity of the blank micelles, while the PTX-loaded micelles providing the cytotoxicity close to that of free PTX. These results indicated that this novel pH-sensitive nano-carriers have great potential applications for oral drug-controlled release.Keywords:nano-carrier;pH-sensitive copolymer;drug release;adamantane
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PubMed
高影响因子
Polymer Chemistry
·
2018
·Vol. 10
·期 2
·228-234
·
IF 4.927
Chao Chen,Xiaofeng Guo,Jinhong Du,Bonnie Choi,Houliang Tang,Anchao Feng,San H. Thang
Miktoarm star (MAS) polymers are polymers with a number of distinct arms connected to a central core. Owing to their exclusive structure, MAS polymers have been extensively studied in recent years. To exploit their biomedical applications the combination of nucleic acids, peptides and saccharides are desired. In this study, RAFT polymerization of three monomers with markedly different properties, N,N-dimethylaminoethyl methacrylate (DMAEMA, cationic), n-butyl methacrylate (BMA, hydrophobic) and oligo(ethylene glycol) methyl ether methacrylate (OEGMA, hydrophilic) was conducted using an RGD peptide based RAFT agent as a chain transfer agent (RGD-CTA). With a disulphide dimethacrylate (DSDMA) redox-cleavable cross-linker, the above linear polymers were combined via an “arm-first” technique to access MAS polymers containing peptide arms. These MAS polymers showed excellent biocompatibility, cell staining performance and rapid redox responsiveness. The novel MAS polymers have potential as a prospective platform for intracellular drug/gene delivery for cancer therapy.
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高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2020
·Vol. 55
·期 22
·9525-9537
·
IF 3.553
Bai Ting,Zhu Bobo,Du Zhaoyi,Shi Junling,Shao Dongyan,Kong Jie
The combination therapy by using two or more chemotherapeutic agents with different action mechanisms has shown to be an attractive strategy for cancer treatment with synergistic therapeutic effects, and also the side effects reduction by one agent replacing part of another one. In this work, an amphiphilic star copolymer with an H40 hyperbranched polyester as the core and poly(ε-caprolactone)-poly(2-dimethylaminoethylmethacrylate) copolymer incorporated with the fluorescent DTM groups as the arms were designed to encapsulate the model anti-cancer drug, doxorubicin (DOX), and a novel potential agent, avasimibe (Ava). Those two drugs could inhibit DNA replication and block acyl-CoA cholesterol acyltransferase-1 (ACAT-1) to induce the cell apoptosis, respectively. The model drugs could be easily loaded into the micelles with a high total drug-loading content toward 24.6% by altering the feeding drug ratios. Three molar ratios (DOX:Ava = 3:1, 1:1, and 1:3) of the drug-loaded micelles were prepared and evaluated for in vitro antitumor efficacy. Results showed that the micelles with 1:1 ratio exhibited the best synergistic cytotoxic activity against both K562 and HeLa cells. Furthermore, the dual-drug combination with efficient anticancer performance was also confirmed by live/dead staining, apoptosis, and cell cycle analysis. Moreover, the internalization of these dual-drug-loaded micelles could be monitored by fluorescent DTM groups and DOX. All these results suggested that the addition of Ava could cut down the dose of DOX to reduce its potential side effects and the co-delivery system could be a promising approach for an effective combination chemotherapy.
研究领域:
药学
·
肿瘤学
·
生物材料
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DOI
高影响因子
POLYMER INTERNATIONAL
·
2016
·Vol. 65
·期 5
·551-558
·
IF 2.414
Shihai Wang,Yu Zhou,Bo Zhuang,Peng Zheng,Hongxiang Chen,Tongcun Zhang,Haiman Hu,Dengcheng Huang
To obtain polyurethane micelles with excellent stability as a drug delivery carrier, star-shaped amphiphilic block polyurethane (SAPU) was successfully synthesized by the ‘arm-first’ method, using methoxypoly(ethylene glycol) and poly(ε-caprolactone) diol as soft segments, hexamethylene diisocyanate as hard segments and pentaerythritol as the core. The structure of the SAPU was characterized by Fourier transform infrared spectroscopy, 1 H NMR spectroscopy and gel permeation chromatography. The micellization behaviour and micelle properties of SAPU were measured by the pyrene fluorescence probe technique, 1 H NMR, SEM and dynamic light scattering. The results indicated that SAPU could self-assemble to form nanomicelles in aqueous solution and that the micelles showed excellent stability upon dilution and storage. Indometacin as a model drug could be incorporated into SAPU micelles and be released sustainedly. Meanwhile, the hydrophilic segment content and the molecular weight of SAPU had effects on the micelle properties. In addition, SAPU exhibited good cytocompatibility estimated by methylthiazole-tetrazolium assay. © 2016 Society of Chemical Industry
研究领域:
材料科学
·
药学
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DOI
高影响因子
危险品化学品经营许可证（带存储）