MACROMOLECULES
·
2020
·
IF 5.918
Lei Cao,Qingqing Zhao,Qizhou Liu,Lei Ma,Chao Li,Xiyu Wang,Yuanli Cai
Electrostatic manipulation of triblock terpolymer nanofilm compartmentalization has been achieved via visible light-initiated reversible addition–fragmentation chain transfer aqueous dispersion polymerization of diacetone acrylamide monomer using cationic–neutral diblock copolymer macro-chain transfer agent (macro-CTA) at 25 °C. This photoinitiated polymerization-induced self-assembly (photo-PISA) evolves into two modes depending on solution pH. At pH 2.5, this macro-CTA dissolves in water with a fully cationic block; electrostatic repulsion leads to conventional aqueous photo-PISA and the formation of monolayer colloidal nanofilms. At pH 7.3, the cationic block transforms to a hydrophobic ionomer block with 10% cationic repeat units, and the copolymer chains self-assemble into weakly cationic micelles, which leads to seeded photo-PISA via self-assembly into discrete nanoclusters within the hydrophobic lamellar framework to form multicompartmentalized monolayer nanofilms. The nanoscale phase-separated 2D-confined nanoclusters and the lamellar structure can be tuned by the ABC/BAC block sequence, the degree of polymerization of the growing block, and the copolymer concentration. This electrostatic manipulation sheds new light on the rational design and preparation of multicompartmentalized block copolymer 2D nanoobjects.
研究领域:
高分子化学
·
纳米材料科学
·
物理化学
✓ 已验证
DOI
高影响因子
REACTIVE & FUNCTIONAL POLYMERS
·
2016
·
IF 2.725
Guiyou Wang,Lingmei Zhang
In this study, well-defined double-hydrophilic triblock copolymers , consisting of hydrophilic poly(ethylene glycol) (PEG) and hydrophobic poly( N , N -diethylamino-2-ethylmethacrylate) (PDEAEMA), were synthesized and characterized. The molecular weights of the copolymers were controllable. In the basic environments, the copolymers can self-assemble into the PDEAEMA core and PEG corona micelles in aqueous solution with an average size of 40–180 nm. The low critical micelle concentration (CMC, about 10 − 3 mg mL − 1 ) of copolymers investigated in pH 7.4 aqueous solution confirmed the adequate thermodynamic stability of their self-assembly. As shown in the cytotoxicity assay, the copolymers have good biocompatibility. Doxorubicin (DOX) was encapsulated into the triblock copolymer micelles . The drug loading efficiency and entrapment efficiency values of DOX-loaded micelles reached 8.14% and 88.6%, respectively. The DOX release of the drug-loaded micelles depends on the pH values. These phenomena indicated that the double-hydrophilic PDEAEMA – PEG – PDEAEMA triblock copolymers have a potential application in the drug delivery.
研究领域:
材料科学
·
药学
·
生物医学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2016
·
IF 5.557
Fen Ran,Kuiwen Shen,Yongtao Tan,Bowu Peng,Shaohua Chen,Weijie Zhang,Xiaoqin Niu,Lingbin Kong,Long Kang
Homopolymer PAN and triblock copolymer PAN- b -PMMA- b -PAN synthesized by RAFT polymerization were used to fabricate activated hierarchical porous carbon membranes by combining phase inversion , carbonization , and HNO 3 activation method; during the preparation process, a lot of micro- and meso-pores generated because of phase separation of PAN and microphase separation of PAN- b -PMMA- b -PAN. The hierarchical porous structure shortened ions transport paths and facilitated the rapid migration of electrolyte ions . When the polymer membrane was prepared by the casting solution with 5 wt% of PAN- b -PMMA- b -PAN and the electrochemical performance was tested at the current densities from 0.5 to 5 A g −1 , a high-end specific capacitance of 297.0 F g −1 and a capacitance retention of 75% were obtained in three-electrode configuration; this specific capacitance remained above 90% of initial value after 2000 cycles at 2 A g −1 in 6 M KOH aqueous solution. Moreover, symmetric supercapacitors assembled with the prepared materials achieved high energy density (15.8 Wh Kg −1 ) and power density (4000 W Kg −1 ) in 1 M Na 2 SO 4 solution. The unique features and structures endowed the electrode membrane with good capacitive performance in both three-electrode and two-electrode configuration, which can be used as electrode membranes for high-performance energy storage devices and other applications.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
MICROELECTRONIC ENGINEERING
·
2021
·
IF 2.523
Fuliang Wang,Yuhang Tian,Kang Zhou,Rui Yang,Tian Tan,Yan Wang,Wenhao Yao
Through silicon via (TSV) is a promising interconnect technology in three-dimensional (3D) integration which has large packing density, improves efficiency and consumes less energy. Since the optimization process of multi-additives system is complicated to achieve void-free TSV copper filling, the use of a single additive become a new trend. In this paper, the using of a triblock copolymer ethylene oxide (EO) - propylene oxide (PO) - ethylene oxide (EO) as a single additive in TSV copper electrodeposition was investigated. High and low concentration of EPE (0.02 g/L and 0.002 g/L) were used for the filling experiment at different current densities. It was found that low concentration EPE had stronger inhibition ability, and achieved “V shape” filling at 0.3 ASD (A/dm 2 ). However, EPE of high concentration would form micelles in electrolyte, resulting in the decrease of inhibition ability. We proposed a mechanism for the different EPE concentrations to explan the phenomenon. In addition, the effect of ultrasonic agitation on EPE filling performance was investigated. With the ultrasonic agitation , bottom-up filling can be achieved at 0.02 g/L, and filling rates can be increased at 0.002 g/L. This can be attributed to the cavitation of the ultrasound which can promote the mass transfer and clean the activated electrode.
研究领域:
材料科学
·
电子工程
✓ 已验证
DOI
高影响因子
MACROMOLECULAR CHEMISTRY AND PHYSICS
·
2019
·Vol. 220
·期 15
·1900187
·
IF 2.622
Haipeng Luo,Yonghui Lin,Qiuju Tang,Wei Hu,Yaping Wang,Zhentao Lei,Zaizai Tong
Regulation of crystalline micelles is difficult to achieve because of the strong solidification of crystallization. In this present work, an amphiphilic triblock copolymer poly(ethylene oxide)- b -poly(ε-caprolactone)- b -poly(4-vinylpyridine) (PEO- b -PCL- b -P4VP) is prepared, in which the P4VP block serves as an H-bonding acceptor. It is originally self-assembled into crystalline lamellar micelles in aqueous solution. Subsequently, the effect of varying pH and organic diacids on morphological transition is investigated in detail. Lamellae-to-cylinder-to-sphere transitions are observed after decreasing the pH or with the addition of organic diacids with different chain spacers. The decreasing pH causes increasing hydrophilicity of the P4VP block, while adding organic diacids results in an increasing corona swelling of the P4VP segment, both of which lead to a decreasing crystallinity of the poly(ε-caprolactone) core. Consequently, morphological variety changing from lamellar to worm-like to spherical micelles can be achieved.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
MACROMOLECULES
·
2022
·
IF 6.057
Guokang He,Peng Wang,Ning Gao,Xianpeng Yin,Fuwei Sun,Wenyun Li,Hongwei Zhao,Chen Wang,Guangtao Li
We report a new type of ABA-type brush-like triblock copolymer (PEGMA-b-PPHMA-b-PEGMA), which is characterized by two hydrophilic end segments (A) and a hydrophobic midblock (B) bearing polymerizable pyrrole moieties. This kind of symmetric triblock copolymers can not only serve as a structure-directing agent for the formation of mesoporous silicates but also function as a polymerizable monomer or carbon source for further chemical conversion to deliver mesostructured polymer or carbon materials within the preformed silicate framework. By utilizing such dual functional macromolecules, rich morphologies of mesostructures are accessible through microphase separation, and the order–order transition among cubic, lamellar, 2D hexagonal, and bicontinuous mesostructures is sensitively achievable by varying the hydrophilic volume fraction of copolymers and TEOS dosage. These features enable facile access to diverse mesostructured silica, polymer, and carbon materials. Remarkably, due to the brush-like polymer architecture and the formation of loop configuration, a widely tunable pore size from mesoscale to macroscale is realizable through using a relatively lower molecular weight copolymer. Importantly, it is found that the brush-like hydrophilic segments of our triblock copolymers can firmly anchor into the silica walls without appreciable escape of copolymer template in commonly used solvents even under reflux extraction, providing a prerequisite for reliable confined chemical transformation into mesostructured polymer and carbon materials. Our work demonstrates that the design and synthesis of functional amphiphilic block copolymers will bring great opportunity for the development of novel mesostructured materials.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2017
·
IF 6.035
Chen Xiao Lin,Xiu Qin Wang,En Ning Hu,Qian Yang,Qiu Gen Zhang,Ai Mei Zhu,Qing Lin Liu
Alkaline stability is the critical issue for the practical application of anion exchange membranes (AEMs) in fuel cells. The benzyltrimethyl ammonium and backbone with C-O linkages of the traditional AEMs are susceptible to attack by hydroxide ions resulting in poor alkaline stability of the AEMs. Herein, we present the preparation of polystyrene-b-poly(ethylene-co-butylene)-b-polystyrene (SEBS) triblock copolymer via grafting, ketone reduction and quaternization for AEM fuel cell applications . The quaternary ammonium (QA) groups are attached to the SEBS backbone free of C-O linkages via long flexible alkyl spacers, which are responsible for the robust alkaline stability of the AEMs. Thus, the hydroxide conductivity of SEBS-CH 2 -QA-1.5 was only decreased by 7.7% and 13.7% after immersing the membranes into a 1 M aqueous KOH solution at 60 and 90 °C for 360 h, respectively. Furthermore, SEBS-CH 2 -QA-1.5 with IEC of 1.23 meq g −1 exhibits a maximum hydroxide conductivity of 56.4 mS cm −1 at 80 °C and a maximum power density of 94.6 mW cm −2 under a current density of 300 mA cm −2 .
研究领域:
材料科学
·
能源科学
✓ 已验证
产品关联
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2016
·
IF 2.76
Yanyun Bai,Xiaoyuan Ma,Wanxu Wang,Qiwen Yin,Zhiping Du,Guoyong Wang
Three polycarboxylate-based comb-like random terpolymers (PAE-Na) were designed and synthesized by emulsion polymerization. Their structures were confirmed by FT-IR, 1 H NMR and GPC. Their surface activities, aggregation behaviors and dispersity properties in aqueous solution were investigated by surface tension measurements, dynamic light scattering (DLS) and transmission electron microscopy (TEM). Investigation of the surface tension indicates that polycarboxylate-based copolymers have good surfactivity due to the introduction of 2-ethylhexyl acrylate (2-EHA). And it is noteworthy that γ continuously decreases after critical aggregation concentration (CAC). TEM and DLS results indicate that they can form the aggregates of primary aggregates. The dispersibility of terpolymers as dispersant for CaCO 3 suspensions was evaluated. The results show that the target polymers have good dispersive capacity. The thermogravimetric analysis indicates that terpolymers have excellent thermal stability, which could be used to disperse solid particles in many different fields.
研究领域:
高分子化学
·
胶体与界面科学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2018
·
IF 8.097
Chen Xiao Lin,Hong Yue Wu,Ling Li,Xiu Qin Wang,Qiu Gen Zhang,Ai Mei Zhu,Qing Lin Liu
To achieve highly conductive and stable anion exchange membranes (AEMs) for fuel cells, novel triblock copolymer AEMs bearing flexible side chain were synthesized. The triblock structure and flexible side chain are responsible for the developed hydrophilic/hydrophobic phase separated morphology and well-connected ion conducting channels, as confirmed by transmission electron microscopy. As a result, the triblock copolymer AEMs with flexible side chain (ABA–TQA-x) demonstrated considerably higher conductivities, up to 130.5 mS cm–1 at 80 °C, than the AEMs with monocation side chain (ABA–MQA). Furthermore, the long alkyl spacer between the backbone and quaternary ammonium groups, as well as long intercation spacer limits the water swelling of the membranes to some degree, resulting in good alkaline stability. The ABA–TQA-44 membrane retained 84.7% and 83.1% of its original conductivity and ionic exchange capacity, respectively, after immersed in a 1 M aqueous KOH solution at 80 °C for 480 h. Furthermore, the peak power density of a H2/O2 single cell using ABA–TQA-44 is 204.6 mW cm–2 at a current density of 500 mA cm–2 at 80 °C.
研究领域:
材料科学
·
能源化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Polymer Chemistry
·
2017
·Vol. 8
·期 45
·6964-6971
·
IF 5.375
Yanxin Qi,Bin Li,Yupeng Wang,Yubin Huang
Given the increasing prosperity of multifunctional poly(ethylene glycol) (mf-PEG), an amphiphilic triblock copolymer, poly(ethylene glycol)-block-poly(ε-caprolactone)-block-poly(allyl glycidyl ether) (mPEG-PCL-PAGE), was synthesized by a combination of living ring-opening polymerization (ROP) and click chemistry. A post-modification of the allyl groups can be achieved via a radical mediated thiol–ene reaction to prepare copolymers bearing side-chain carboxylic or amino groups [mPEG-PCL-PAGE(R)]. The chemical structures and compositions of these polymers were systematically characterized using Fourier transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance spectroscopy (1H NMR) and gel permeation chromatography (GPC). The copolymers could readily assemble into micelles in aqueous solution as confirmed by fluorescence spectroscopy, dynamic light scattering (DLS), transmission electron microscopy (TEM) and zeta potential measurements. MTT and hemocompatibility assays indicated that the micelles showed no associated cytotoxicity and could be potentially used for nanomedicine. Intriguingly, the specific sequence of [mPEG-PCL-PAGE(R)] showed pH-induced morphology transformation, while the corresponding polymer with a middle PAGE segment [mPEG-PAGE(R)-PCL] did not, which, we propose, was attributed to the tunable hydrophilicity and distinctive folding of the molecular chain at varied pH values. This finding offers a route to regulate the self-assembly behaviors in polymer systems by controlling the block sequence.
研究领域:
材料科学
·
生物医学工程
·
纳米医学
✓ 已验证
产品关联
DOI
高影响因子
MACROMOLECULES
·
2010
·
IF 4.539
Keping Chen,Neil Grant,Liyun Liang,Haifei Zhang,Bien Tan
Amphiphilic block copolymers poly(ethylene glycol)-block-oligo(vinyl acetate) (PEG-b-OVAc) and OVAc-b-PEG-b-OVAc have been demonstrated to be effective surfactants for CO2-in-water (C/W) emulsions. However, the high cost and difficulty of synthesis process can render the economics of CO2 process unfavorable. In this work, by reversible addition−fragmentation chain transfer (RAFT) polymerization, a series of well-defined CO2-philic triblock copolymers X−OVAc-b-PEG-b-OVAc−X (where X stands for xanthate group) were synthesized. The structures and molecular weights of these copolymers were characterized by 1H NMR and GPC. The results of GPC analysis exhibited relatively narrow polydispersity (PDI < 1.35). The process of preparation of X−OVAc-based surfactants was much more simple, inexpensive and also easy to control, which could promote industrial-scale applications. The X−OVAc-based surfactants were found effectively to produce highly concentrated stable C/W emulsions. Porous emulsion-templated materials were prepared by the polymerization of the continuous phase of C/W emulsions. The open-cell morphology of the emulsion-templated materials was evidenced by scanning electron microscope. To tune the morphology of the porous structures, the influence of the surfactant concentration and molecular weight of OVAc block were also investigated. It was shown that X−OVAc-based surfactants can outperform perfluorinated surfactants and approach OVAc-based surfactants for such applications.
研究领域:
高分子化学
·
材料科学
·
表面活性剂化学
✓ 已验证
DOI
高影响因子
MACROMOLECULES
·
2022
·
IF 6.057
Huagao Fang,Xingchen Gao,Fan Zhang,Wenjuan Zhou,Guobin Qi,Kai Song,Sheng Cheng,Yunsheng Ding,H. Henning Winter
Vitrimer chemistry of boronic transesterification was introduced into a triblock thermoplastic elastomer to allow associative bond exchange in its highly ordered nanoscale domains. The purpose of this localized dynamic cross-linking is to enable reprocessing while also improving creep resistance. Triblock poly(styrene-b-butadiene-b-styrene) (SBS) was used as an elastomeric vitrimer precursor to gain understanding of fundamental structure–property effects of localized dynamical cross-linking. The occurrence of the UV-induced thiol–ene reaction was corroborated by Fourier transform infrared (FTIR) spectroscopy and swelling experiments. Transmission electron microscopy (TEM) images and small-angle X-ray scattering (SAXS) profiles demonstrate a prominently lamellar morphology with domain spacings that decline with the increase of cross-linking degree. Short and long relaxation modes of triblock SBS vitrimers (vSBSs) were found to have opposite temperature dependence, which caused thermorheological complexity in linear viscoelasticity. As compared to its random analog, vSBS shows much slower stress relaxation and higher activation energy, as well as superior resistance to creep under a steady load. The enhanced rheological properties are attributed to the high concentration of localized cross-links in the soft phase and to additional constraints that hinder network strand diffusion in the microphase-separated structure. The mechanical properties of vSBSs at low strain were substantially enhanced by the associative dynamic cross-links between the soft segments, increasing the maximum stress to 7.5 MPa at 100% strain. Its Young’s modulus of 88.1 MPa is about 2.8 times that of neat SBS. Applications of vSBSs as hot-melt adhesives were explored, showing excellent lap shear strength on iron plates. Due to the dynamic exchange of boronic ester bonds, adhesive joints can efficiently rebind at least three times and the lap shear strength remains almost unchanged.
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）