APPLIED SURFACE SCIENCE
·
2017
·
IF 3.387
Fangfang Chen,Jiayu Wang,Huiru Chen,Ruicong Lu,Xiaoyu Xie
Magnetic nanoparticles have been widely used as support core for fast separation, which could be directly separated from complicated matrices using an external magnet in few minutes. Surface imprinting based on magnetic core has shown favorable adsorption and separation performance, including good adsorption capacity, fast adsorption kinetics and special selectivity adsorption. Reversible addition–fragmentation chain transfer (RAFT) is an ideal choice for producing well-defined complex architecture with mild reaction conditions. We herein describe the preparation of well-constructed magnetic molecularly imprinted polymers (MMIPs) for the recognition of benzimidazole (BMZ) residues via the microwave-assisted RAFT polymerization . The merits of RAFT polymerization assisting with microwave heating allowed successful and more efficient preparation of well-constructed imprinted coats. Moreover, the polymerization time dramatically shortened and was just 1/24th of the time taken by conventional heating. The results indicated that a uniform nanoscale imprinted layer was formed on the Fe 3 O 4 core successfully, and enough saturation magnetization of MMIPs (16.53 emu g −1 ) was got for magnetic separation. The desirable adsorption capacity (30.18 μmol g −1 ) and high selectivity toward template molecule with a selectivity coefficient ( k ) of 13.85 of MMIPs were exhibited by the adsorption isothermal assay and competitive binding assay, respectively. A solid phase extraction enrichment approach was successfully established for the determination of four BMZ residues from apple samples using MMIPs coupled to HPLC. Overall, this study provides a versatile approach for highly efficient fabrication of well-constructed MMIPs for enrichment and determination of target molecules from complicated samples.
研究领域:
分析化学
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材料科学
·
食品科学
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DOI
高影响因子
Polymer Chemistry
·
2014
·Vol. 5
·期 14
·4277-4284
·
IF 5.368
Xueteng Cao,Chunlei Zhang,Songbai Wu,Zesheng An
We have developed a highly efficient, one-step approach for the synthesis of core cross-linked star (CCS) polymers using commercial macromonomers (polyethylene glycol methyl ether methacrylates) as the arms via RAFT-mediated emulsion polymerization in aqueous media. This approach employs a small molecular chain transfer agent (CTA), commercial macromonomer, hydrophobic cross-linker, and optional hydrophobic spacing monomer as the polymerization recipe to synthesize CCS polymers via direct one-step polymerization in aqueous buffer solution. Various polymerization parameters, including buffer concentration and molar ratio of macromonomer/cross-linker/spacing monomer relative to CTA, were investigated. CCS polymers of high yield and low dispersity were obtained within 4 h under a wide range of conditions. Analysis of polymerization kinetics and macromolecular parameters of the generated polymeric species during the polymerization process led to insights into the mechanistic aspects of the CCS formation process, which was proposed to involve three stages, i.e., polymer chain growth, cross-linking to form CCS, and CCS growth. Finally, synthesis of CCS polymers using macromonomers of different molecular weights pointed to the necessity for optimization of the polymerization conditions for each macromonomer, possibly due to different polymerization rates and steric hindrance.
研究领域:
高分子化学
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材料科学
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产品关联
DOI
高影响因子
POLYMER
·
2018
·
IF 3.483
Jun He,Dongdong Liu,Jianbo Tan,Li Zhang
We report a novel blue light initiated aqueous reversible addition–fragmentation chain transfer (RAFT) dispersion polymerization of 2-hydroxypropyl methacrylate (HPMA) with a poly (glycerol monomethacrylate) homopolymer as the macro-RAFT agent and sodium bis(acyl)phosphane oxide (SBAPO) as the photoinitiator . High monomer conversions were achieved within 1 h of blue light irradiation . Taking advantage of the temperature-insensitive feature of photoinitiator , the effect of reaction temperature on the blue light initiated aqueous RAFT dispersion polymerization was studied in detail. A new morphological phase diagram was constructed for the first time by changing the degree of polymerization (DP) of the core-forming block and the reaction temperature. Moreover, a typical morphological phase diagram for the blue light initiated aqueous RAFT dispersion polymerization at 70 °C was also built and various morphologies have been prepared. Effect of wavelength of light (405 and 465 nm) on copolymer compositions and morphologies was studied. Finally, a fully one-pot blue light initiated aqueous RAFT polymerization was developed for the synthesis of various diblock copolymer nano-objects.
研究领域:
高分子化学
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光化学
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材料科学
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纳米技术
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高分子工程
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DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2017
·
IF 3.648
Yingge Shi,Dazhuang Xu,Meiying Liu,Lihua Fu,Qing Wan,Liucheng Mao,Yanfeng Dai,Yuanqing Wen,Xiaoyong Zhang,Yen Wei
Fluorescent organic nanoparticles (FONs) have attracted intensive research interest for a variety of biomedical applications. Therefore, preparation of novel FONs with excellent optical properties and good biocompatibility in rather facile manner is of utmost importance. In this work, FONs based on dopamine (DA) containing copolymers were facilely fabricated through the combination of reversible addition–fragmentation chain transfer (RAFT) polymerization and self-polymerization of DA containing copolymers (poly(AC- co -PEGMA)), which were obtained by the one-pot polymerization of poly(ethylene glycol) methacrylate and acryloyl chloride in the present of DA. To generate these FONs, polyethyleneimine (PEI) was mixed with polymer-DA conjugates under rather mild experimental conditions (e.g. room temperature , absent of catalysts, air atmosphere and aqueous solution). Results confirmed polymer-DA-PEI FONs owned excellent water dispersibility and strong green fluorescence and desirable biocompatibility. All of these features make polymer-DA-PEI FONs alternative candidates for biomedical applications. In conclusion, we developed a rather facile strategy to fabricate novel types of FONs through the combination of RAFT polymerization and self-polymerization of DA. Because of the good monomer adaptability, this strategy could also be used for fabrication of many other FONs with different functional groups and properties.
研究领域:
材料科学
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生物医学工程
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产品关联
DOI
高影响因子
BIOMACROMOLECULES
·
2017
·
IF 5.246
Wen-Jian Zhang,Chun-Yan Hong,Cai-Yuan Pan
An ingenious formulation of RAFT dispersion polymerization based on photosensitive monomers of 2-nitrobenzyl methacrylate (NBMA) and 7-(2-methacryloyloxy-ethoxy)-4-methyl-coumarin (CMA) is reported herein. Various morphologies, such as spherical micelle, nanoworm, lamella, and vesicle, are fabricated at up to 20% solids content. Photoinduced cleavage of the NBMA moieties and dimerization of the coumarin moieties are simultaneously triggered upon UV (365 nm) irradiation. The former endows the cores of the nano-objects with abundant carboxyl groups, resulting in the transformation of the hydrophobic cores to hydrophilic ones. The latter induces the core-cross-linking of the nano-objects, which endows the nano-objects with enhanced structural stability and prevents the nanoparticle-to-unimer disassembly. The resultant nano-objects exhibit superior structural stability and excellent performances for drug delivery, including high drug loadings, pH-stimuli release, and high-efficient endosomal escape.
研究领域:
材料科学
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药学
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生物医学工程
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产品关联
DOI
PubMed
高影响因子
TALANTA
·
2016
·
IF 4.035
Yonghua Xiao,Rong Xiao,Jian Tang,Qiankun Zhu,Xiaoming Li,Yan Xiong,Xuewen Wu
The molecularly imprinted polymers (MIP) were prepared via aqueous RAFT precipitation polymerization, with aristolochic acid I (AAI) as the template molecule, AA as the functional monomer , EGDMA as the cross-linker, AIBN as the chain initiator, CTP as the chain transfer agent and 80% (g/g) DMF-aqueous solution as the porogen . The differential UV–vis spectra revealed that a cooperative hydrogen-bonding complex between AAI and AA might be formed at the molar ratio of 1:3 in prepolymerized system. The synthesized MIPs were characterized by FTIR spectra, solid UV–visible absorption spectra, nitrogen adsorption-desorption isotherms and scanning electron microscope, which proved that the MIPs and NIPs have the similar chemical structures and the adding of AAI could affect the size and morphology of the microspheres . UV–visible absorption spectra and High-performance liquid chromatography (HPLC) was used to investigate the adsorption and recognition properties of the MIPs. The Scatchard isotherm model described that the binding sites independently acted. The Langmuir isotherm model suggested an excellent imprinting effect owing to the presence of a large number of specific binding sites on the MIP. The Freundlich model indicated that the AAI could be readily absorbed by MIP. Selective absorption of the template molecule was demonstrated in presence of its analogous compounds, benzoic acid and nitrobenzene . The recycling experiments implied that the MIP could be reused to further selective recognition and separation to AAI for six times at least. MIP was developed for removal of AAI from the Aristolochia manshuriensis extraction. The results indicated that 25 mg of MIP could remove the AAI below the HPLC detection limits (6.47 ng mL -1 ) from 5.0 mL of the extraction (CAAI=0.0018 mg mL -1 ) with the recovery of AAI to 91.50% (n=3, SD=4.24%). Therefore, it is clearly revealed that the MIP can be a useful tool to remove toxic compounds from natural products .
研究领域:
分析化学
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药物化学
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环境科学
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DOI
高影响因子
Polymer Chemistry
·
2015
·Vol. 6
·期 21
·4020-4029
·
IF 5.52
Jianbing Huang,Lvhuan Lin,Hui Liang,Jiang Lu
A facile synthetic route to branched graft copolymers has been developed by combination of self-condensing vinyl polymerization (SCVP), reversible addition–fragmentation chain transfer (RAFT) polymerization and aldehyde–aminooxy reaction. RAFT polymerization of 2-(dimethylamino)ethyl methacrylate (DEM) in the presence of a newly designed aldehyde-containing chain-transfer monomer, 6-(2-formyl-4-vinylphenoxy)hexyl-2-(dodecylthiocarbonothioylthio)-2-methylpropanate (FHDM), led to branched polyDEM (BPDEM) bearing aldehyde functionalities on its branching points. The degree of branching and the average branch length of the resulting BPDEM can be readily tuned by manipulation of the DEM/FHDM feed ratio. The aldehyde groups on the branching points of BPDEM were then reacted with aminooxy-terminated poly(ethylene oxide)s (PEO-ONH2), affording the structurally well-defined branched graft copolymer BPDEM-g-PEO with a branched polyDEM backbone and PEO grafted chains. The thermo-induced micellization behavior of BPDEM-g-PEO in water was investigated. Opportunities are open for BPDEM-g-PEO to form either multimolecular micelles or unimolecular micelles via simply adjusting the chain length of grafted PEO. Further modification of BPDEM-g-PEO by quaternization resulted in branched cationic polyelectrolytes which are capable of capturing negatively charged guest molecules via electrostatic complexation to form in situ self-assembled nanoparticles with simultaneous encapsulation of the guests.
研究领域:
高分子化学
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材料科学
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DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2019
·Vol. 43
·期 22
·8517-8526
·
IF 3.069
Zhiwu Chen,Hui Cao,Tianwei Tan
A well-defined functional star polymer nanoparticle was prepared using an “arm first” approach via RAFT polymerization. In this work, N-adamantylacrylamide and N-succinimidyl acrylate were copolymerized with N-isopropylacrylamide sucessfully. The obtained diblock copolymer regarded as an “arm” endowed the star polymer with multiple conjugate functions. By adjusting the amount of crosslinking agent, the size and polydispersity of the star polymer were controlled. With the star polymer as the scaffold, a sequential multi-enzyme system was constructed, where HRP was placed in the inner layer through covalent conjugation, and β-cyclodextrin-modified GOx was assembled in the outer layer through host–guest recognition. More interestingly, the activity of the enzyme modified by β-cyclodextrin was improved. In addition to the enhanced thermal stability, this multienzyme system also exhibited a reduced Km value (from 2.18 mM to 0.39 mM) and an excellent substrate affinity. The specificity constant (Kcat/Km) for GOx in the star polymer@HRP@GOx system was 1.7-fold higher than that of the free HRP with free GOx system. This strategy will promote the development of biocatalysis reactions and biosensors as a promising method.
研究领域:
生物化学
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材料科学
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生物催化
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产品关联
DOI
高影响因子
MACROMOLECULAR CHEMISTRY AND PHYSICS
·
2022
·Vol. 224
·期 4
·2200369
·
IF 2.996
Weiwei Liu,Shuangkun Zhang,Zhi Luo,Tao Zou,Pingye Deng,Zhanpeng Wu,Haiqiao Wang
Novel thermoplastic fluorinated polyacrylate films possessing excellent mechanical performance are prepared by emulsion polymerization latex using adjustable amphiphilic star macro-reversible addition-fragmentation chain-transfer (macro-RAFT) agent as surfactants in this work. First, star macro-RAFT agent equipped with six amphiphilic arms is synthesized via two-step RAFT polymerization of acrylic acid (AA) and 2,2,2-trifluoroethyl acrylate (TFEA) in the presence of hexa-functional RAFT agents. The surface activities of the as-synthesized amphiphilic star macro-RAFT agents in aqueous solutions are studied. Subsequently, various fluorinated polyacrylate latexes are obtained by conducting emulsion polymerization of 2,2,3,4,4,4-hexafluorobutyl acrylate (HFBA) and butyl acrylate (BA) using the amphiphilic star macro-RAFT agents as both RAFT agents and surfactants. The latex particle morphologies are studied by transmission electron microscope (TEM) and particle size is measured by dynamic light scattering (DLS). The effects of PAA segment length, HFBA/BA mole ratio, and TFEA segment length on the surface morphologies of the fluorinated polyacrylate films are illustrated by investigating the surface properties using water contact angle test and atomic force microscopy (AFM). Finally, the elastomeric films obtained by directly casting the prepared fluorinated polyacrylate latexes show excellent comprehensive properties such as tensile strength over 4 MPa, elongation at break ≈700%, permanent deformation below 25%. Water absorption test is also provided as a reference.
研究领域:
材料科学
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高分子化学
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产品关联
DOI
高影响因子
COLLOID AND POLYMER SCIENCE
·
2020
·Vol. 299
·期 4
·663-674
·
IF 1.536
Xia Yunfei,Xu Xiuhang,Yu Haihua,Zhou Chuan,Nie Zhenzhou,Yang Jianfeng,Qian Jiajia,Ni Henmei
Zwitterionic microspheres of poly2-(dimethylamino) ethyl methacrylate (PDMAEMA) block polymethacrylic acid (MAA) were prepared by RAFT dispersion polymerization in alcohols. 4-Cyano-4-(phenylcarbonothioylthio) pentanoic acid (CPDB) was used as the RAFT agent. 2,2′-Azobis(2,4-dimethyl) valeronitrile (V65) was used as the initiator, and PDMAEMA-CPDB was used as the macro-chain transfer agent (CTA). 1 HNMR was applied to determine the polymerization degrees of both PDMAEMA-CTA and PDMAEMA-b-PMAA. SEM, dynamic light scattering (DLS), and small-angle X-ray diffraction (SAX) were employed to characterize the microspheres. It was observed that the polarity of alcohols impacted the partition of MAA and V65 between the mini-droplets of PDMAEMA-CTA/MAA complexes and the continuous phase, thereby affected on the diameters of microspheres, the total conversion of MAA, and the polymerization degree of PMAA in the copolymers. For example, in methanol, the smallest diameter and polymerization degree of PMAA in the block copolymers were obtained, whereas the total conversion of MAA of the RAFT polymerization system was the highest. Most of RAFT polymerization of MAA occurred nearby PDMAEMA-CTA chains; thus, PDMAEMA-CTA acted as a template to regulate the length of PMAA in the copolymers. pH-sensitive characteristics of microspheres were dependent to the extra length of PDMAEMA-CTA, i.e., the difference of lengths between two blocks. When the length of PMAA was too short, e.g., PDMAEMA 600 -b-PMAA 87 , or the length of PMAA was closed to that of PDMAEMA, e.g., PDMAEMA 79 -b-PMAA 93 and PDMAEMA 102 -b-PMAA 131 , the amphoteric characteristics of microspheres disappeared. The self-assembly behavior of diblock copolymers in KCl alcohol-water solution was also determined by the extra length of PDMAEMA. Microspheres turned into nanofibers or nano-ribbons, but for PDMAEMA 600 -b-PMAA 87 , the microspheres maintained their original spheric morphology. These results indicated that the charge-screening effects of salts played the key roles in the self-assembly.
Graphical abstract
研究领域:
高分子化学
·
材料科学
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产品关联
DOI
高影响因子
Polymer Chemistry
·
2016
·Vol. 8
·期 7
·1163-1176
·
IF 5.687
Xue Jiang,Feng Chun,Guolin Lu,Huang Xiaoyu
The monomer, 2,2,2-trifluoroethyl 3-(N-(2-(diethylamino)ethyl)acrylamido)propanoate (TF-DEAE-AM), which contains both O2 and CO2-responsive functionalities, was first synthesized from commercially available N,N-diethylethylenediamine, 2,2,2-trifluoroethyl acrylate, and acryloyl chloride. Subsequently, a series of dual-gas responsive polymers, poly(2,2,2-trifluoroethyl 3-(N-(2-(diethylamino)ethyl)acrylamido)propanoate) (poly(TF-DEAE-AM)) and poly(ethylene glycol)-b-poly(2,2,2-trifluoroethyl 3-(N-(2-(diethylamino)ethyl)acrylamido)propanoate) (PEG-b-poly(TF-DEAE-AM)), were synthesized by employing reversible addition–fragmentation chain transfer (RAFT) polymerization. Due to the protonation between CO2 and DEAE groups, and the specific van der Waals interactions between O2 and C–F bonds, micelles consisting of poly(TF-DEAE-AM) or PEG-b-poly(TF-DEAE-AM) display distinct CO2 and O2 responsiveness in aqueous media. Pyrene, which is a model hydrophobic drug, is able to be effectively encapsulated in the micelles based on PEG-b-poly(TF-DEAE-AM). It is found that the release of pyrene sharply increases after bubbling CO2 or O2 compared to N2, and the release rate of the solution bubbling with CO2 is the fastest. Since both CO2 and O2 are key gases for the human body, the CO2- and O2-induced release property of poly(TF-DEAE-AM) may open opportunities for the preparation of functional materials with special CO2 and O2 responsiveness for potential applications in biomedicine.
研究领域:
高分子化学
·
生物材料
·
药物递送
·
刺激响应材料
·
生物医学工程
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DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2014
·
IF 2.235
Xiaohui Li,Wen-Jun Wang,Feiyin Weng,Bo-Geng Li,Shiping Zhu
Copolymer composition distribution (CCD) is an important parameter of chain microstructure that has significant impact on the material properties of polymer products. Controlled/living radical polymerization (CLRP) has provided a great opportunity in producing polymers with predesigned CCDs through a model-based monomer feeding policy (MMFP) in homogeneous systems. In this work, the MMFP has been expanded to heterogeneous systems. Reversible addition–fragmentation transfer (RAFT) mini-emulsion polymerizations of styrene (St) and butyl acrylate (BA) were carried out with 3-benzyltrithiocarbonyl propionic acid (BCPA) used as a RAFT agent. A kinetic model was developed and correlated to the batch St/BA RAFT mini-emulsion experimental data for parameter estimation. The MMFP was then developed by combining the kinetic model with a semibatch reactor model and applied to the semibatch St/BA RAFT mini-emulsion copolymerization for the synthesis of targeted CCDs. The model agreed well with the polymerization kinetics. A series of St/BA copolymers with predesigned CCDs were successfully synthesized.
研究领域:
高分子化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）