Polymer Chemistry
·
2018
·Vol. 9
·期 30
·4150-4160
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IF 4.927
Qian Li,Xiao Li,Zhongying Wu,Yuhao Sun,Jianglin Fang,Dongzhong Chen
Tetraphenylethylene (TPE) is one of the well-known typical aggregation-induced emission (AIE) luminogens (AIEgens) and TPE-containing polymers possess excellent processing properties which facilitates the fabrication of various AIE systems and devices. For AIE active side-chain polymers, increasing the fluorescence quantum yield through suitable molecular design is very appealing. In this work, we present the well-controlled synthesis of a series of TPE polyacrylate side-chain polymers of Pm with short spacers with methylene number m = 0–5 via RAFT polymerization. All the obtained polymers exhibit typical and strong AIE characteristics in THF/H2O solution mixtures and in solid state films. In particular, greatly enhanced fluorescence emission is achieved with reduced spacer lengths, and further significant improvement achieved through annealing, which is ascribed to the restriction of intramolecular motions (RIM) and the blocking of the non-radiative channels due to overcrowding and confinement thanks to the strong positive coupling effect and the jacketing effect of side-chain polymers with very short spacers. The quantum yields of 34.4%, 32.0% and 31.4%, respectively, for the polymer films P0, P1 and P2 are several times higher than those of homologous polymers with longer spacers reported in the literature. Based on these TPE side-chain polymers of very short spacers, a simple, economic and visual method for detection of the explosive 2,4,6-trinitrotoluene (TNT) is demonstrated. Therefore, a facile approach and feasible strategy of simply adopting very short spacers for side-chain AIE active polymer preparation to significantly enhance the luminescence efficiency has been properly established and proposed, which may provide guidance and have a wealth of implications for the rational design and preparation of highly efficient luminescent AIE polymer materials.
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JOURNAL OF MOLECULAR LIQUIDS
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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.
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APPLIED SURFACE SCIENCE
·
2022
·
IF 7.392
Hong Li,Jianhua Zhou,Jiaojiao Zhao
Polymeric coatings are easy to be damaged by harsh environment condition, which causes cracks and loss of function. Inspired by the natural self-healing phenomenon, we successfully synthesized dual-functional cellulose nanocrystals/fluorinated polyacrylate containing coumarin derivatives by RAFT-assisted Pickering emulsion polymerization . The amphiphilic and photo-responsive copolymer , PDMAEMA- b -PGMA- b -P(HFBA- co -VBMC) was synthesized by RAFT process, followed by characterization using FT-IR, SEC , 1 H NMR and UV–vis. The cellulose nanocrystals were modified by the copolymer, which were confirmed via XPS, UV–vis and so on. Besides, the droplet size of Pickering emulsion gradually increased and the creaming layer gradually decreased as the pH value increased. The TEM result showed that the modified cellulose nanocrystals were effectively anchored on the outside of latex particles. The size of the spherical-like latex particles increased and the stability of latex particles was worse with increasing pH value. Finally, the finished fabric had excellent water resistance due to the combination of micro- or nanoscale hierarchical structure and low surface energy. Moreover, the latex film exhibited excellent repeatability of self-healing ability. The fabric coating achieved the intrinsic and superficial dual-functional self-healing performance by the reversible [2 + 2] cycloaddition of coumarin groups. This strategy provides a powerful guide for preparing the high-performance waterborne fluorinated polyacrylate coating.
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Journal of Materials Chemistry A
·
2021
·Vol. 9
·期 46
·26010-26018
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IF 12.732
Junhao Jiang,Jinpeng Li,Jun Qian,Xiaoyun Liu,Peiyuan Zuo,You Yuan,Qixin Zhuang
Polymer nanocomposites with high energy density have become a research hotspot in the field of dielectric materials. However, the huge compatibility contrast between nanofillers and polymers always hinders the further improvement of dielectric properties. Meanwhile, next-generation dielectrics should possess excellent thermal stability to cope with the development of high-temperature applications. Herein, a novel polymer nanocomposite based on heat-resistant poly(p-phenylene benzobisoxazole) (PBO) and high-permittivity CaCu3Ti4O12 (CCTO) nanoparticles was prepared by the solution method. In this process, electroactive polymer poly(2-isopropenylbenzoxazole) (P(2-IBO)), which has a chemical structure similar to PBO and contains numerous permanent dipoles, is selected as the modifier to optimize the electric field behavior at the interface, and it is coated on the surface of CCTO nanoparticles via surface-initiated reversible addition–fragmentation chain transfer (RAFT) polymerization for achieving controllable dielectric properties. The results demonstrate that the dielectric properties can be adjusted by changing the thickness of the P(2-IBO) shell. The breakdown strength and energy density of the modified CCTO/PBO nanocomposites are much higher than those of the unmodified CCTO/PBO nanocomposites. Under an electric field of 200 kV mm−1, the maximum discharge energy density reaches 3 J cm−3, which is about 500% that of pure PBO (0.6 J cm−3). Moreover, the dielectric properties are nearly independent of the testing temperature (25 to 200 °C), indicating that this nanocomposite is an ideal candidate for high-temperature dielectric materials.
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BIOMACROMOLECULES
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2017
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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.
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PubMed
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2016
·
IF 3.349
Yan Liu,Jian Qiu,Yinhua Jiang,Zhanchao Liu,Minjia Meng,Liang Ni,Changchun Qin,Jianbo Peng
Ce(III) ion-imprinted polymer (Ce(III)-IIP) grafted on Fe 3 O 4 nanoparticles supported by SBA-15 mesopores microreactor was successfully synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization for selective removal of Ce(III) from aqueous solution. The characterization results suggest that the surface ion-imprinted polymer (IIP) synthesized by RAFT is a thin layer. Adsorption isotherm experiments indicated that Redlich-Peterson isotherm model best fitted the experimental data and the adsorption capacity of IIP was obviously higher than that of non-imprinted polymers (NIP) at the same conditions. The kinetics of adsorption followed the Thomas model. Moreover, competitive adsorption studies illustrated that Ce(III)-IIP offers the advantages of selectivity towards Ce(III) compared with NIP even in the presence of other metal ions. All above results indicated the potential application of Ce(III)-IIP for selective removal of Ce(III) from aqueous solution.
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RSC Advances
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2015
·Vol. 5
·期 92
·75766-75772
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IF 3.84
Lei Li,Guohua Jiang,Xiangxiang Du,Hua Chen,Yongkun Liu,Qin Huang,Xiangdong Kong,Juming Yao
A glucose-responsive and fluorescent copolymer was prepared via a one-pot method that combines RAFT polymerization and enzymatic transesterification. The as-prepared copolymer tended to self-assemble into spherical micelles that were confirmed using 1H NMR, FT-IR and GPC, and transmission electron microscopy (TEM) and dynamic light scattering (DLS) analysis. Due to the attachment of fluorescent side groups, the optical properties of the micelles were analyzed using a UV-Vis spectrometer, fluorescence spectrophotometer and confocal laser scanning microscopy (CLSM). Owing to the amphiphilic and glucose-responsive properties, the micelles could be used as carriers for loaded insulin. The insulin release behaviour was evaluated when triggered by glucose in vitro. In addition, the resultant micelles exhibited relatively lower cytotoxicity and excellent stability against a protein solution. The insulin retained its structure stability after release, investigated through circular dichroism (CD) spectra analysis. These results showed that the obtained glucose-responsive and fluorescent polymer micelles with a good biological imaging performance and biocompatibility could be one of the effective candidate carriers for controllable release of insulin.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2014
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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.
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高影响因子
RSC Advances
·
2014
·Vol. 5
·期 14
·10611-10618
·
IF 3.708
Jinhua Li,Ruichen Dong,Xiaoyan Wang,Hua Xiong,Shoufang Xu,Dazhong Shen,Xingliang Song,Lingxin Chen
A facile strategy was developed to prepare magnetic molecularly imprinted microspheres (MMIMs) for the selective recognition and effective removal of 17-beta-estradiol (17β-E2) by reversible addition-fragmentation chain transfer precipitation polymerization. One-pot synthesis was employed, which could simplify the imprinting process and shorten the experimental period. The resultant MMIMs displayed fast kinetics and high binding capacity, and the adsorption processes followed Langmuir–Freundlich isotherm and pseudo-second-order kinetic models. Excellent recognition selectivity toward 17β-E2 was attained over other phenolic estrogens such as 17-alpha-E2, estriol and estrone. The magnetic property of MMIMs provided fast and simple separation, and the recycling process for magnetic solid phase extraction (MSPE) was sustainable at least five times without obvious efficiency decrease. Furthermore, the MMIMs-MSPE presented satisfactory recoveries within 71.7–108.3% with the precisions of 1.1–6.0% for spiked 17β-E2 in water, soil and food samples. The developed MMIMs-based method proved to be a convenient and practical way in sample pretreatment and targeted pollutants removal.
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RSC Advances
·
2015
·Vol. 5
·期 17
·12517-12529
·
IF 3.84
Xiangguo Meng,Yan Liu,Minjia Meng,Zheyu Gu,Liang Ni,Guoxing Zhong,Fangfang Liu,Zhaoyong Hu,Rui Chen,Yongsheng Yan
In this work, two novel Cs(I) ion-imprinted polymers (Cs(I)-IIP1 and Cs(I)-IIP2) have been prepared by surface imprinting technique based on support matrix of SBA-15. The strategy was carried out by introducing two different reversible addition–fragmentation chain transfer (RAFT) polymerization including using the free RAFT agent in solution and surface-anchored RAFT agent with appropriate initiation method, which is expected to generate a well-defined surface ion-imprinted polymer with excellent adsorption capacity. The materials were verified by FT-IR, SEM, TEM, nitrogen adsorption–desorption and TGA. Owing to the intrinsic advantages of surface-anchored RAFT polymerization, the resultant surface ion-imprinted polymer (Cs(I)-IIP2) exhibited more homogeneous and thinner polymer layer (15 nm) with excellent macrostructure in comparison to Cs(I)-IIP1 (75 nm) prepared by using the free RAFT agent in solution. Furthermore, the adsorption capacity of both polymers are compared, indicating that Cs(I)-IIP2 displays higher adsorption property and excellent selectivity for Cs(I).
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Polymer Chemistry
·
2024
·Vol. 15
·期 29
·2992-3002
·
IF 4.1
Wen Li,Guoyu Chen,Youfang Zhang,Jianyun Ding,Jie Liu,Runguo Wang,Dean Shi,Weiwei Lei,Liqun Zhang
In recent years, myrcene has emerged as a biobased alternative to isoprene for the manufacture of thermoplastic elastomers due to its similarity to isoprene, a building block for natural rubber. Through the use of highly reactive tert-butyl acrylate as a hard segment monomer, a structurally well-defined poly(tert-butyl acrylate)-b-poly(β-myrcene)-b-poly(tert-butyl acrylate) (BMB) thermoplastic triblock copolymer elastomer was synthesized by a mild reversible addition–fragmentation chain transfer (RAFT) emulsion polymerization method utilizing a precisely devised amphiphilic macro-RAFT agent. The block copolymer BMB was confirmed by NMR, FTIR, and GPC analyses. BMB thus exhibits typical thermoplastic elastomeric properties, as indicated by its mechanical properties with an ultimate tensile strength of 3.0 MPa and an elongation at break of 195% with tert-butyl acrylate added at 50% mass ratio. The properties of BMB can be easily tuned by adjusting the hydrolysis degree, facilitating cooperative interactions in the hard phase and enhancing tensile properties. This carboxyl interaction is an effective strategy for controlling medium strength thermoplastic elastomers.
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MACROMOLECULAR CHEMISTRY AND PHYSICS
·
2020
·Vol. 221
·期 18
·2000148
·
IF 2.335
Mengyuan Zhang,Yang Xue,Shixian Zhang,Jianhua Zhang,Ruiwei Guo
Regioselective addition of nonsymmetrical monomers in radical polymerization is a basic issue for control of the reaction kinetics and structure of the resulting products. In reversible addition-fragmentation chain transfer (RAFT) polymerization, head addition generates primary alkyl adducts when trapped by RAFT agents. Due to the low leaving ability of primary alkyl radicals, this kind of adduct in RAFT polymerization will become nonactive macro-RAFT agents, that is, dead dormant species (DDS). Based on the previously-developed equation for the correlation of DDS content (α) with head-addition incidence (ρ 1 ) in RAFT polymerization and the quantitative determination method of DDS content by coupling a block-polymerization derivatization with gradient polymer elution chromatography analysis, the ρ 1 values of methyl acrylate (MA) at different temperatures are determined with benzyl N -carbazolecarbodithioate (BCBD) as RAFT agent and 2-methyloxyethyl acrylate as the second monomer for block-polymerization derivatization. The results show that the ρ 1 values of MA at 60, 70, 80, and 90 °C are 2.04 × 10 −3 , 2.37 × 10 −3 , 2.72 × 10 −3 , and 3.28 × 10 −3 , respectively, and the activation energy for ρ 1 is 15.8 kJ mol −1 . The DDS in BCBD-mediated RAFT polymerization of MA is separated by column chromatography and characterized by 1 H-NMR and MALDI-TOF MS.
研究领域:
高分子化学
·
材料科学
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