43 results on '"Yaochen Zheng"'
Search Results
2. Metal-coordination-driven self-assembly synthesis of porous iron/carbon composite for high-efficiency electromagnetic wave absorption
- Author
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Yan Li, Yusheng Qin, Guanglei Wu, Yaochen Zheng, and Qingfu Ban
- Subjects
Biomaterials ,Colloid and Surface Chemistry ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials - Published
- 2022
3. Hierarchical engineering of Large-caliber carbon Nanotube/Mesoporous Carbon/Fe3C nanoparticle hybrid nanocomposite towards Ultra-lightweight electromagnetic microwave absorber
- Author
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Qingfu Ban, Yan Li, Yusheng Qin, Yaochen Zheng, Xiubo Xie, Zhen Yu, and Jie Kong
- Subjects
Biomaterials ,Colloid and Surface Chemistry ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials - Published
- 2022
4. Diagnosis and analysis of twin-tube shock absorber rattling noise in electric vehicle
- Author
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Tingting Zheng, Yaochen Zheng, Xiaoping Gong, Peiran Li, and Yangjia She
- Subjects
Materials Science (miscellaneous) ,Business and International Management ,Industrial and Manufacturing Engineering - Abstract
To address the rattling noise issue of a Twin-tube hydraulic shock absorber for a electric vehicle, a road test and subjective evaluation were performed. The diagnostic method of the rattling noise source of the shock absorber is studied, and three methods are used to process the test date: the fast Fourier transform can only obtain the main frequency band of the rattling noise; and the short-time Fourier transform can roughly diagnose the frequency band and the occurrence time; using wavelet transform technology combined with displacement signal can accurately lock the source of rattling noise in the rebound stroke. Furthermore, combined with the internal valve configuration of the shock absorber, the rattling noise source is diagnosed in the rebound valve and the compensation valve. The time of rattling noise and the corresponding working stroke of shock absorber can be quickly locked by using the wavelet transform, which is of great significance to solve the problem of shock absorber rattling noise caused by deficiency design of the internal valve architecture of the shock absorber.
- Published
- 2022
5. Squeak and Rattle recognition based on speaker recognition
- Author
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Yaochen Zheng, Ruijiao Cai, Zhaoxiang Deng, and Peiran Li
- Subjects
Materials Science (miscellaneous) ,Business and International Management ,Industrial and Manufacturing Engineering - Abstract
Squeak and Rattle problems seriously affect the quality of the vehicles. In the adjustment stage of the automobile development process, engineers mainly rely on subjective evaluation to diagnose squeak and rattle noises, which is prone to misjudgment, missed judgment and time-consuming problems. There are gaps in relevant objective evaluation methods. This article proposed that speaker identification is used to identify squeak and rattle noises from the audio recorded in the test, to achieve objective and accurate results. In this paper, four kinds of squeak and rattle noise audios are used as samples, Mel Frequency Cepstrum Coefficient is extracted as feature vector to construct target Gaussian mixture models (GMM). The expectation, variance and correlation coefficient of the Gaussian mixture model can be calculated to describe the difference of multiple squeak and rattle noises. Using samples to judge accuracy rate, the results indicated that the acceptance accuracy rate reaches 100 %, and the rejection accuracy rate reaches more than 95 %.
- Published
- 2022
6. High‐performance epoxy composites improved by uniformly dispersed and partly thermal reduced graphene oxide sheets
- Author
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Hui Xu, Zhiqing Liu, Chenghui Qiao, Xintao Zhang, Qi Zhang, Yuerong Zhang, and Yaochen Zheng
- Subjects
Polymers and Plastics ,Materials Chemistry ,General Chemistry ,Surfaces, Coatings and Films - Published
- 2022
7. Transparent and toughening epoxy thermosets modified by linear telechelic polymer containing rigid spiroacetal moieties: Uncovering the relationship between the heterogeneous crosslinked network and thermoset performances
- Author
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Liu Shaoxiang, Jian Liu, Chenghui Qiao, Peng Song, Ban Qingfu, Yaochen Zheng, Mengqing Wu, Zhengguo Gao, and Xu Hui
- Subjects
Telechelic polymer ,Materials science ,Polymers and Plastics ,visual_art ,Materials Chemistry ,Click chemistry ,visual_art.visual_art_medium ,Thermosetting polymer ,Epoxy ,Physical and Theoretical Chemistry ,Composite material ,Transparency (behavior) ,Toughening - Published
- 2021
8. Effect of the topology on the antibacterial activity of cationic polythioether synthesized by all‐click chemistry
- Author
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Gao Xuan, Ban Qingfu, Tao He, Yaochen Zheng, Jian Liu, Yan Guo, Qian Zhang, and Zhengguo Gao
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Polymers and Plastics ,Chemistry ,Materials Chemistry ,Cationic polymerization ,Click chemistry ,Physical and Theoretical Chemistry ,Antibacterial activity ,Combinatorial chemistry ,Topology (chemistry) - Published
- 2020
9. Spherical covalent organic frameworks supported black phosphorus@Au nanocatalysts for nitrophenol hydrogenation in a high efficiently flow-through process
- Author
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Yaochen Zheng, Xiaole Qi, Fenyan Xiao, Fushuai Wang, and Ning Wang
- Subjects
General Physics and Astronomy ,Surfaces and Interfaces ,General Chemistry ,Condensed Matter Physics ,Surfaces, Coatings and Films - Published
- 2023
10. Hierarchically nanostructured carbon nanotube/polyimide/mesoporous Fe2O3 nanocomposite for organic-inorganic lithium-ion battery anode
- Author
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Qingfu Ban, Yuanyuan Liu, Peiyan Liu, Yan Li, Yusheng Qin, and Yaochen Zheng
- Subjects
Mechanics of Materials ,General Materials Science ,General Chemistry ,Condensed Matter Physics - Published
- 2022
11. Graphene dispersed by pyrene‐terminated polyethylene glycol for reinforced epoxy composites
- Author
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Yaochen Zheng, Hui Xu, Heshun Jing, Qingxin Ren, Zhiqing Liu, Zhengguo Gao, and Qingfu Ban
- Subjects
Polymers and Plastics ,Materials Chemistry ,General Chemistry ,Surfaces, Coatings and Films - Published
- 2022
12. Variable-stiffness composite cylinder design under combined loadings by using the improved Kriging model
- Author
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Yaochen Zheng, Jifan Zhong, Zhao Jing, and Jianqiao Chen
- Subjects
business.industry ,Mechanical Engineering ,Computational Mechanics ,Internal pressure ,02 engineering and technology ,Structural engineering ,01 natural sciences ,010305 fluids & plasmas ,020401 chemical engineering ,Buckling ,Kriging ,Ovality ,0103 physical sciences ,Genetic algorithm ,Bending moment ,Torque ,Cylinder ,0204 chemical engineering ,business ,Mathematics - Abstract
The large design freedom of variable-stiffness (VS) composite material presupposes its potential for wide engineering application. Previous research indicates that the design of VS cylindrical structures helps to increase the buckling load as compared to quasi-isotropic (QI) cylindrical structures. This paper focuses on the anti-buckling performance of VS cylindrical structures under combined loads and the efficient optimization design method. Two kinds of conditions, bending moment and internal pressure, and bending moment and torque are considered. Influences of the geometrical defects, ovality, on the cylinder’s performances are also investigated. To increase the computational efficiency, an adaptive Kriging meta-model is proposed to approximate the structural response of the cylinders. In this improved Kriging model, a mixed updating rule is used in constructing the meta-model. A genetic algorithm (GA) is implemented in the optimization design. The optimal results show that the buckling load of VS cylinders in all cases is greatly increased as compared with a QI cylinder.
- Published
- 2018
13. Catalyst-free and thermal-induced S→O acetyl migration reaction to generate the polyacrylate polythiols for anticorrosion use
- Author
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Jin Han, Cheng Chen, Zhong Mingqiang, Jieze Shen, Shu Tian, Zhixiong Liu, Yaochen Zheng, and Qingquan Xue
- Subjects
chemistry.chemical_classification ,Tafel equation ,Polymers and Plastics ,Organic Chemistry ,chemistry.chemical_element ,Salt (chemistry) ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Copper ,0104 chemical sciences ,Corrosion ,Catalysis ,Corrosion inhibitor ,chemistry.chemical_compound ,chemistry ,Intramolecular force ,Polymer chemistry ,Materials Chemistry ,Thiol ,0210 nano-technology - Abstract
A catalyst-free and thermal-induced S→O acetyl migration (SOAM) reaction was occasionally found and used to fabricate the polythiol corrosion inhibitor. The route to prepare the polythiols was free of catalyst and side products. Only intramolecular migration process existed, while intermolecular migration was not found. Temperature-dependent 1H NMR experiment showed the conversion rate of the SOAM reaction was 83% at 160 °C. Further heating at higher temperature or for longer reaction time, the conversion rate did not increase. It was speculated that there was equilibrium between two reversible migrations. The prepared polythiol inhibitor contains a large amount of latent thiol groups after the SOAM reaction process. The strong Cu S bonds immediately formed and made the polythiol chains firmly anchored on the copper surface when the copper metal was coated with the polythiols. Also S S bond formation reaction leads to dense crosslinking and film formation. Raman spectrum and SEM were used to characterized the protective film. A smooth and defect-free film with thickness of 1.9 μm was achieved when the copper sample was immersed in the polythiol solution for 60 min. The corrosion performance of the film is obtained by potential and impedance measurements and Tafel curves by immersing in a 3.5 wt% NaCl solution. All of the coated samples exhibited significantly lower corrosion rates than the bare copper sample, and the corrosion rate decreased as the immersion time increased. The inhibtion efficiency of the polythiol inhibitor was up to 99.3%. Neutral salt spray experiments indicated that the polythiol films provided excellent protection for over one week. The polythiols were also very stable in storage and have application in designing various polyacrylate polythiols resins.
- Published
- 2018
14. Co-assembly-driven nanocomposite formation techniques toward mesoporous nanosphere engineering: A review
- Author
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Yusheng Qin, Jie Kong, Yaochen Zheng, and Qingfu Ban
- Subjects
chemistry.chemical_classification ,Aqueous solution ,Nanocomposite ,Materials science ,Nanotechnology ,General Chemistry ,Polymer ,Condensed Matter Physics ,Nanomaterials ,Template ,chemistry ,Mechanics of Materials ,Amphiphile ,Copolymer ,General Materials Science ,Mesoporous material - Abstract
Mesoporous nanospheres are of great importance in the cutting-edge fields of energy, catalysis and sensor technology, mainly because of their multilevel architectures, tunable meso-structures, specific compositions and soft-templated synthesis approaches. In this review, the control mechanisms of aqueous polymer self-assembly are first elaborated based on the correlated driving forces, methods, and initial conditions. Then, recent advances of co-assembly-driven nanocomposite formation techniques toward mesoporous nanosphere engineering using amphiphilic block copolymers and low-molecular-weight surfactants as soft templates are systematically reviewed. Here, soft templates and organic or inorganic precursor species as well as their co-assembly processes and formation mechanisms are elaborated to thoroughly understand co-assembly-driven nanocomposite formation techniques. After soft template removal through high-temperature pyrolysis or solvent extraction, mesoporous nanospheres can be obtained. Generally, this review presents insights and a guideline to co-assembly-driven engineering of mesoporous nanospheres and promotes the development of this emerging interdisciplinary research field at the frontier between organic polymer co-assembly and inorganic nanomaterial fabrication.
- Published
- 2021
15. Intramolecular cyclization in hyperbranched star copolymers via one-pot Am+Bn+C1 step-growth polymerization resulting in decreased cyclic defect
- Author
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Yusheng Qin, Jie Kong, Yaochen Zheng, Qingfu Ban, and Yan Li
- Subjects
Aqueous solution ,Polymers and Plastics ,Organic Chemistry ,General Physics and Astronomy ,02 engineering and technology ,Vinyl ether ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Step-growth polymerization ,chemistry.chemical_compound ,Monomer ,chemistry ,Polymerization ,Polymer chemistry ,Materials Chemistry ,Copolymer ,medicine ,Molar mass distribution ,0210 nano-technology ,Macromolecule ,medicine.drug - Abstract
Hyperbranched star copolymers are important soft materials that have been employed for aqueous self-assembly and bioapplication, but their one-pot one-batch synthesis strategy and relevant topology are rarely discussed. In this contribution, we produce hyperbranched star poly(vinyl ether ester)s (mPEG-hb-PVEEs) amphiphiles with multimodal molecular weight distribution via one-pot one-batch Am+Bn+C1 (m ≥ 2, n ≥ 3) step-growth polymerization. Based on the topological analysis of these hyperbranched star copolymers, a convenient expression of the number ratio of monomeric structural units (NA/NB) is deduced to describe the cyclic defect of intramolecular cyclization only by using proton nuclear magnetic resonance spectroscopy. The introduction of long-chain terminators and the change in the molar feed ratio of A2:B3:C1 considerably affect the NA/NB so as to give rise to increased influence of number of macromolecules and decreased influence of intramolecular cyclization, which are then responsible for an aqueous self-assembly behavior of mPEG-hb-PVEEs amphiphiles. Overall, this study opens new possibilities for the precise description of intramolecular cyclization and controllable synthesis of hyperbranched star copolymers via one-pot Am+Bn+C1 step-growth polymerization.
- Published
- 2021
16. A modified multi-objective particle swarm optimization approach and its application to the design of a deepwater composite riser
- Author
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Junwei Chen and Yaochen Zheng
- Subjects
Mathematical optimization ,021103 operations research ,Optimization problem ,Computer science ,Mechanical Engineering ,Numerical analysis ,0211 other engineering and technologies ,Computational Mechanics ,Particle swarm optimization ,Computational intelligence ,02 engineering and technology ,Multi-objective optimization ,Kriging ,Genetic algorithm ,0202 electrical engineering, electronic engineering, information engineering ,020201 artificial intelligence & image processing ,Multi-swarm optimization - Abstract
A modified multi-objective particle swarm optimization method is proposed for obtaining Pareto-optimal solutions effectively. Different from traditional multi-objective particle swarm optimization methods, Kriging meta-models and the trapezoid index are introduced and integrated with the traditional one. Kriging meta-models are built to match expensive or black-box functions. By applying Kriging meta-models, function evaluation numbers are decreased and the boundary Pareto-optimal solutions are identified rapidly. For bi-objective optimization problems, the trapezoid index is calculated as the sum of the trapezoid’s area formed by the Pareto-optimal solutions and one objective axis. It can serve as a measure whether the Pareto-optimal solutions converge to the Pareto front. Illustrative examples indicate that to obtain Pareto-optimal solutions, the method proposed needs fewer function evaluations than the traditional multi-objective particle swarm optimization method and the non-dominated sorting genetic algorithm II method, and both the accuracy and the computational efficiency are improved. The proposed method is also applied to the design of a deepwater composite riser example in which the structural performances are calculated by numerical analysis. The design aim was to enhance the tension strength and minimize the cost. Under the buckling constraint, the optimal trade-off of tensile strength and material volume is obtained. The results demonstrated that the proposed method can effectively deal with multi-objective optimizations with black-box functions.
- Published
- 2017
17. Scalable Synthesis of Positively Charged Sequence-Defined Functional Polymers
- Author
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Bo Zhao, Chao Gao, Yaochen Zheng, and Zhengguo Gao
- Subjects
chemistry.chemical_classification ,Chemistry ,Cationic polymerization ,General Chemistry ,Polymer ,010402 general chemistry ,01 natural sciences ,Biochemistry ,Combinatorial chemistry ,Catalysis ,Cycloaddition ,0104 chemical sciences ,Colloid and Surface Chemistry ,Yield (chemistry) ,Molecule ,Polar ,Reactivity (chemistry) ,Functional polymers - Abstract
Synthesizing and characterizing sequence-defined polymers with positively charged backbone are great challenges. By alternately processing Menschutkin reaction and Cu-catalyzed azide-alkyne cycloaddition reaction, we successfully synthesized series of scalable cationic sequence-defined polymers with quaternary ammonium backbone up to 12 repeating units and characterized their precise structures. Due to the dramatic polarity difference between weak polar feed molecules and strong polar target molecules, simple precipitation in weak polar solvents is enough to obtain pure sequence-defined polymers. Such a polar-inverse strategy (PIS), without protecting groups and solid support, offers extremely high yields up to 68% after 12 reaction steps (i.e., average yield95% for each step), favoring cost-effective large-scale production. Because of the independent reactivity of selected functional groups, the cationic sequence-defined polymers are highly programmable, including backbone composition, sequence order, functional side groups, terminal groups and topological structure. Sequence information decoding is easily achieved according to Maldi-Tof mass spectrum without retrospecting its synthetic history, resulting in a great superiority in the field of information transmitting and reading. The resulting multifunctional sequence-defined polymers are water-soluble and positively charged, opening the avenue to bioapplications such as condensing DNA, gene transfection and drug delivery.
- Published
- 2019
18. Maximizing the Load Carrying Capacity of a Variable Stiffness Composite Cylinder Based on the Multi-Objective Optimization Method
- Author
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Jifan Zhong, Jianqiao Chen, Junxiang Li, Ben Han, and Yaochen Zheng
- Subjects
Composite cylinder ,Variable stiffness ,Computer science ,business.industry ,Composite number ,02 engineering and technology ,Structural engineering ,Maximization ,021001 nanoscience & nanotechnology ,Multi-objective optimization ,Load carrying ,Computational Mathematics ,020303 mechanical engineering & transports ,0203 mechanical engineering ,Computer Science (miscellaneous) ,0210 nano-technology ,business - Abstract
Variable stiffness (VS) composite structures can greatly increase the composite designability and thus have attracted much attention in recent years. This paper focuses on the maximization of load carrying capacity of VS composite cylinders under different loading cases, and the multi-objective optimization method is used to get the optimal results. First, the VS composite cylinder is optimized under four single loading cases. The results show that the anti-buckling capacity of the VS cylinder is better than the constant stiffness (CS) counterpart. The active learning Kriging surrogate model (AK) is applied to the cylinder optimization and the accuracy and efficiency of AK are verified. Under combined loading cases, the multi-objective particle swarm optimization is used to obtain the final Pareto-optimal solutions. The results indicate that the loading capacity of the VS cylinder is much greater than CS cylinder in the cases studied.
- Published
- 2021
19. Dome shape optimization of filament-wound composite pressure vessels based on hyperelliptic functions considering both geodesic and non-geodesic winding patterns
- Author
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Jianqiao Chen, Qunli An, Yaochen Zheng, Ji Zhou, and Zhu Wang
- Subjects
Filament winding ,Specific modulus ,Materials science ,Geodesic ,Mechanical Engineering ,Composite number ,Astrophysics::Instrumentation and Methods for Astrophysics ,Geometry ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Pressure vessel ,Specific strength ,Protein filament ,020303 mechanical engineering & transports ,0203 mechanical engineering ,Mechanics of Materials ,Materials Chemistry ,Ceramics and Composites ,0210 nano-technology ,Hyperelliptic curve - Abstract
Filament-wound composite pressure vessels, owing to the advantages of their high specific strength, specific modulus and fatigue resistance, as well as excellent design performance, have been widely used in energy engineering, chemical industry and other fields. A filament-wound composite pressure vessel generally consists of two parts, a cylindrical drum part and the dome parts. In the cylindrical drum part, the filament winding angle and the winding layer thickness can be easily determined due to the regular shape. In the dome parts, however, both the winding angle and the thickness vary along the meridian line. Performance of the dome parts, which strongly depends on the effect of end-opening and the winding mode, dominates the performance of a pressure vessel. In this paper, optimum design of the dome parts is studied by considering both geodesic winding and non-geodesic winding patterns. A hyperelliptic function is adopted as the basis function for describing the meridian of the dome shape. The dome contour is optimized by taking the shape factor (S.F.) as the objective and parameters in the basis function as the design variables. A specific composite pressure vessel is taken as the numerical analysis example with varying dome shape which is to be optimized. The optimum design solution is obtained through the particle swarm optimization algorithm. It shows that an optimized dome with non-geodesic winding has better S.F. as compared with geodesic winding. Influences of the slippage coefficient and the polar opening on the S.F. are also discussed.
- Published
- 2016
20. Group interval-controlled polymers: an example of epoxy functional polymers via step-growth thiol–yne polymerization
- Author
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Li Peng, Chao Gao, Yaochen Zheng, Zhulin Weng, Bo Zhao, Han Xu, Zhengguo Gao, Yu Jin, and Shengying Cai
- Subjects
chemistry.chemical_classification ,Polymers and Plastics ,010405 organic chemistry ,Organic Chemistry ,Bioengineering ,Polymer ,Epoxy ,010402 general chemistry ,Thioester ,01 natural sciences ,Biochemistry ,0104 chemical sciences ,Gel permeation chromatography ,chemistry.chemical_compound ,chemistry ,Polymerization ,visual_art ,Polymer chemistry ,visual_art.visual_art_medium ,Click chemistry ,Azide ,Functional polymers - Abstract
We have coined a new term, group interval-controlled polymers (GICPs), to describe the unique structure of macromolecules with a tunable functional group interval. The precise control of a polymer main chain structure itself is still a big challenge, let alone the purposeful control of group interval simultaneously. Here, we successfully synthesized a series of epoxy GICPs via one-step UV-triggered thiol–yne polymerization of commercial glycidyl propargyl ether and dithiols at 0 °C. Subsequently, α,ω-thiols of each epoxy GICP were capped by two allyl glycidyl ethers via a thiol–ene click reaction, affording a stable product. Their unique group interval-controlled chemical structures were confirmed by a combination of nuclear magnetic resonance (NMR), gel permeation chromatography (GPC) and pyrene-fluorescent probe tests. Moreover, the epoxy groups within the GICPs were highly reactive and could be further functionalized and turned into a diverse range of customized groups such as azide, tertiary amino, thioester, and hydroxyl, etc. Therefore, a series of GICPs with designed functional groups are readily achieved on a large scale. Our work presents a reliable synthetic methodology for GICPs, paving a new way for the precise structure control of artificial macromolecules.
- Published
- 2016
21. High porosity microspheres with functional groups synthesized by thiol–yne click suspension polymerization
- Author
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Zhulin Weng, Yaochen Zheng, Bo Zhao, Chao Gao, Zhengguo Gao, and Shengying Cai
- Subjects
chemistry.chemical_classification ,Polymers and Plastics ,Metal ions in aqueous solution ,Organic Chemistry ,technology, industry, and agriculture ,Bioengineering ,02 engineering and technology ,Polymer ,Polyethylene glycol ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Biochemistry ,0104 chemical sciences ,chemistry.chemical_compound ,Adsorption ,Chemical engineering ,chemistry ,PEG ratio ,Monolayer ,Polymer chemistry ,Surface modification ,Suspension polymerization ,0210 nano-technology - Abstract
Porous polymer microspheres have been widely used in various fields, such as in ion-adsorption and drug release, and as catalyst carriers and so on. However, the facile synthesis of polymer microspheres with various available functional groups is still a challenge. Here, we firstly synthesized epoxy-functionalized porous microspheres via thiol–yne suspension polymerization of glycidyl propargyl ether and 1,3-propanedithiol, using 1,7-octadiyne as a crosslinker and polyethylene glycol (PEG) as a porogen. The epoxy groups on the microsphere surfaces were further modified to tert-amine, thioacetate, and carboxyl groups via thiol–epoxy click reactions. The morphologies of the porous microspheres were investigated using a scanning electron microscope (SEM). When the content of PEG was 35 wt%, porous polymer microspheres with average diameters of ∼70 μm and highest porosities of 62.45% were obtained. Subsequently, diverse modified porous microspheres were used to adsorb copper ions that were dissolved in DMF. Among these as-prepared microspheres, the thioacetate-functionalized one exhibited the highest Cu2+ adsorption capacity (158 mg g−1) at room temperature. Exploration of its adsorption behaviors illustrated that the thioacetate-functionalized microspheres followed a chemically controlled monolayer adsorption mechanism. Our work presents a brand new reliable strategy for the synthesis and functionalization of non-degradable epoxy-containing porous microspheres, which can be used for the adsorption or removal of toxic metal ions (such as copper ions).
- Published
- 2016
22. Amphiphilic Hyperbranched Polymers: Synthesis and Host-Guest Supermolecular Coloring Application
- Author
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Zhulin Weng, Zhengguo Gao, Chao Gao, Yaochen Zheng, Yu Jin, Aijin Tang, and Shengying Cai
- Subjects
Materials science ,Polymers and Plastics ,Polymer science ,Organic Chemistry ,Hyperbranched polymers ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,Amphiphile ,Materials Chemistry ,Self-assembly ,Physical and Theoretical Chemistry ,0210 nano-technology ,Host (network) - Published
- 2015
23. Thiol-yne Click Polymerization
- Author
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Chao Gao and Yaochen Zheng
- Subjects
chemistry.chemical_classification ,chemistry.chemical_compound ,Monomer ,Nucleophilic addition ,chemistry ,Thioether ,Polymerization ,Click chemistry ,Polymer ,Hybrid material ,Branching (polymer chemistry) ,Combinatorial chemistry - Abstract
Thiol-yne click polymerization (TYCP) is one of the most significant synthetic techniques for artificial polymers, due to its simplicity, efficiency, and functionality tolerance. In nature, it is a classic nucleophilic addition reaction and a step-growth polymerization, which can be initiated or accelerated in the presence of free-radicals, amines, and transition metals, respectively. Its rate is greatly influenced by the structures (i.e., their electrophilicity and steric hindrance) of the used thiols and/or alkynes. With aliphatic monomers being used as feeding materials, the topological architectures (such as linear, branching, and cross-linked network, etc.) and available functional groups (such as hydroxyl, carboxyl, amino, and epoxy groups, and so on) can be facilely tailored via altering the chemical structure and feeding order. In contrast, for aromatic monomers, mono-addition occurs only during the process of thiol-yne click reaction, leading exclusively to linear poly(vinyl thioether)s. These sulfur-containing polymers synthesized by TYCP are promising to be widely utilized as high refractive index materials, photovoltaic materials, drug-delivery vehicles, biomaterials, and hybrid materials, etc.
- Published
- 2018
24. Current Chemistry of Cyclic Oligomeric Silsesquioxanes
- Author
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Jin Han, Yaochen Zheng, and Zhengguo Gao
- Subjects
010405 organic chemistry ,Chemistry ,Organic Chemistry ,Nanotechnology ,Current (fluid) ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences - Published
- 2018
25. POSS-based Amphiphiles: Synthesis and Use in Self-assembling Nanosystems and Nanomaterials
- Author
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Yuan Gao, Yan Sheng, Yaochen Zheng, Jin Han, and Zhengguo Gao
- Subjects
Chemistry ,Organic Chemistry ,Self assembling ,Amphiphile ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,0210 nano-technology ,01 natural sciences ,0104 chemical sciences ,Nanomaterials - Published
- 2018
26. Monolithic Neat Graphene Oxide Aerogel for Efficient Catalysis of S → O Acetyl Migration
- Author
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Chao Gao, Li Jiachen, Li Peng, Yu Jin, and Yaochen Zheng
- Subjects
geography ,geography.geographical_feature_category ,Materials science ,Graphene ,Inorganic chemistry ,Oxide ,Aerogel ,General Chemistry ,Photochemistry ,Catalysis ,law.invention ,chemistry.chemical_compound ,Unpaired electron ,chemistry ,law ,Specific surface area ,Cage effect ,Monolith - Abstract
Graphene oxide (GO) is highly attractive for catalysis because of its large specific surface area and rich chemical structures. However, it has generally been used as a catalyst carrier. Here, we designed a three-dimensional monolith of neat GO aerogel as a fixed-bed carbocatalyst used in the reaction of S → O acetyl migration for the synthesis of thiol compounds, showing the merits of ultrafast catalytic speed (5–8 h), high selectivity (100%), high yields (near 100%), easy isolation of products, and long-life recyclability (>18 times). Particularly, we achieved for the first time thiol compounds containing functional groups of halogen and hydroxyl, which cannot be synthesized using other currently reported catalysts. Control experiments demonstrated that the efficient catalysis mechanism is mainly attributed to the protonic functional groups, ultralarge size, and unpaired electrons of GO, as well as the “cage effect” at nanoscale confined spaces of aerogel cells.
- Published
- 2015
27. Hyperbranched polymers: advances from synthesis to applications
- Author
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Sipei Li, Yaochen Zheng, Chao Gao, and Zhulin Weng
- Subjects
chemistry.chemical_compound ,Monomer ,Materials science ,chemistry ,Polymerization ,Supramolecular chemistry ,Surface modification ,Nanotechnology ,General Chemistry ,Hybrid material ,Cycloaddition ,Ene reaction ,Macromolecule - Abstract
Hyperbranched polymers (HPs) are highly branched three-dimensional (3D) macromolecules. Their globular and dendritic architectures endow them with unique structures and properties such as abundant functional groups, intramolecular cavities, low viscosity, and high solubility. HPs can be facilely synthesized via a one-pot polymerization of traditional small molecular monomers or emerging macromonomers. The great development in synthetic strategies, from click polymerization (i.e., copper-catalyzed azide-alkyne cycloaddition, metal-free azide-alkyne cycloaddition, strain-promoted azide-alkyne cycloaddition, thiol-ene/yne addition, Diels-Alder cycloaddition, Menschutkin reaction, and aza-Michael addition) to recently reported multicomponent reactions, gives rise to diverse HPs with desirable functional/hetero-functional groups and topologies such as segmented or sequential ones. Benefiting from tailorable structures and correspondingly special properties, the achieved HPs have been widely applied in various fields such as light-emitting materials, nanoscience and technology, supramolecular chemistry, biomaterials, hybrid materials and composites, coatings, adhesives, and modifiers. In this review, we mainly focus on the progress in the structural control, synthesis, functionalization, and potential applications of both conventional and segmented HPs reported over the last decade.
- Published
- 2015
28. Novel triethylamine catalyzed S → O acetyl migration reaction to generate candidate thiols for construction of topological and functional sulfur-containing polymers
- Author
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Tianhui Ren, Gang Wang, Yanqin Gao, Xuedong Wu, Yaochen Zheng, Jin Han, Li Peng, and Chao Gao
- Subjects
chemistry.chemical_classification ,General Chemical Engineering ,Disulfide bond ,General Chemistry ,Polymer ,Epoxy ,Ring (chemistry) ,Topology ,Sulfur containing ,Catalysis ,chemistry.chemical_compound ,chemistry ,visual_art ,Thiol ,visual_art.visual_art_medium ,Triethylamine - Abstract
We describe a novel triethylamine catalyzed S → O acetyl migration reaction for yielding thiol compounds under mild conditions through the formation of a transitional 5-membered ring. A series of epoxy compounds have been transformed into their thiol counterparts which could be used for construction of topological and functional sulfur-containing polymers. The one-pot two-step processes including the S → O acetyl migration and the following thiol-click reactions avoided separation of thiol intermediates. Applying these processes on a new-type latent polythiols overcomes crosslinking problem usually met in preparation of multithiol compounds due to the formation of disulfide bonds.
- Published
- 2015
29. The electrophilic effect of thiol groups on thiol–yne thermal click polymerization for hyperbranched polythioether
- Author
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Bo Zhao, Chao Gao, Zhulin Weng, Yaochen Zheng, and Shengying Cai
- Subjects
chemistry.chemical_classification ,Polymers and Plastics ,Organic Chemistry ,Bioengineering ,Branching (polymer chemistry) ,Biochemistry ,Gel permeation chromatography ,Reaction rate constant ,chemistry ,Polymerization ,Electrophile ,Polymer chemistry ,Thiol ,Spectroscopy - Abstract
This paper firstly revealed the electrophilic effect of thiol groups on thiol–yne polymerization. For this, we designed and synthesized five kinds of α-thiol-ω-alkynyl AB2 type intermediates with thiols with different electrophilicities. The thiol electrophilic effect can be assessed by chemical shift (δ) and measured directly by nuclear magnetic resonance (NMR) spectroscopy. As the evidence from gel permeation chromatography (GPC) and NMR tracking measurements shows, the polymerization rate and molecular weight (MW) were significantly enhanced as the thiol electrophilic effect reduced. On the contrary, with increasing electrophilicity of the thiol, the resultant degrees of branching (DBs) increased. The semiquantitative relation between reactive rate constant (k) and δ (or electrophilicity of thiol) can be expressed by k = 2.41–1.34δ. Therefore, important features of thiol–yne polymerization and HPTEs, such as rate constant (k), MW, DB, etc., can be roughly estimated in advance by the NMR measurement of the thiol's electrophilic effect.
- Published
- 2015
30. Copolymer architecture effects on the morphology and surface performance of epoxy thermosets containing fluorinated block copolymers
- Author
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Yan Sheng, Yaochen Zheng, Qingquan Xue, Lemin Zhu, Ren Wanzhong, and Zhirong Xin
- Subjects
Nanocomposite ,Materials science ,Polymers and Plastics ,Scanning electron microscope ,Thermosetting polymer ,Epoxy ,Condensed Matter Physics ,Methacrylate ,Surface energy ,Contact angle ,Chemical engineering ,visual_art ,Polymer chemistry ,Materials Chemistry ,Copolymer ,visual_art.visual_art_medium ,Physical and Theoretical Chemistry - Abstract
The architecture effects on phases and surface enrichment behaviors of epoxy nanocomposites containing fluorinated block copolymers are investigated by the incorporation of two novel copolymers composed of poly (2, 2, 2-trifluoroethyl methacrylate) (PTFEMA) and poly (e-caprolactone) (PCL), PCL-b-PTFEMA and PTFEMA-b-PCL-b-PTFEMA, with identical molecular weight and composition. These fluorinated copolymers in epoxy display distinguished self-assembled structures, as evidenced by dynamic laser scattering and scanning electron microscopy measurements. Static contact angle detection suggests that the nanocomposites display an obvious improvement in surface water repellency and a reduction in surface free energy. The enhancement in surface hydrophobicity is attributed to the enrichment of PTFEMA blocks at the nanocomposite surface and to the formation of the specific surface morphology, as confirmed by atomic force microscopy. The different architectures of the two block copolymers give rise to differences in phase-structures, and the ultimate surface performances of composites. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014, 52, 1037–1045
- Published
- 2014
31. Modeling of pedestrian evacuation based on the particle swarm optimization algorithm
- Author
-
Xiwei Guo, Junhong Wei, Jianqiao Chen, and Yaochen Zheng
- Subjects
Computer Science::Multiagent Systems ,Statistics and Probability ,Computer science ,Evolutionary algorithm ,Particle swarm optimization ,Contrast (statistics) ,Particle ,Pedestrian ,Nonlinear Sciences::Cellular Automata and Lattice Gases ,Condensed Matter Physics ,Constant (mathematics) ,Algorithm - Abstract
By applying the evolutionary algorithm of Particle Swarm Optimization (PSO), we have developed a new pedestrian evacuation model. In the new model, we first introduce the local pedestrian’s density concept which is defined as the number of pedestrians distributed in a certain area divided by the area. Both the maximum velocity and the size of a particle (pedestrian) are supposed to be functions of the local density. An attempt to account for the impact consequence between pedestrians is also made by introducing a threshold of injury into the model. The updating rule of the model possesses heterogeneous spatial and temporal characteristics. Numerical examples demonstrate that the model is capable of simulating the typical features of evacuation captured by CA (Cellular Automata) based models. As contrast to CA-based simulations, in which the velocity (via step size) of a pedestrian in each time step is a constant value and limited in several directions, the new model is more flexible in describing pedestrians’ velocities since they are not limited in discrete values and directions according to the new updating rule.
- Published
- 2012
32. Synthesis and characterization of heptaphenyl polyhedral oligomeric silsesquioxane-capped poly(N-isopropylacrylamide)s
- Author
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Sixun Zheng, Lei Wang, and Yaochen Zheng
- Subjects
Materials science ,Aqueous solution ,Polymers and Plastics ,Organic Chemistry ,Radical polymerization ,General Physics and Astronomy ,Nuclear magnetic resonance spectroscopy ,Lower critical solution temperature ,Silsesquioxane ,chemistry.chemical_compound ,Dynamic light scattering ,chemistry ,Polymer chemistry ,Materials Chemistry ,Click chemistry ,Poly(N-isopropylacrylamide) - Abstract
In this work, a novel initiator bearing heptaphenyl polyhedral oligomeric silsesquioxane (POSS) was synthesized via the copper-catalyzed Huisgen 1,3-cycloaddition (i.e., click chemistry). With this initiator, the atom transfer radical polymerization (ATRP) of N -isopropylacrylamide (NIPAAm) was carried out to afford the POSS-capped PNIPAAm. The organic–inorganic amphiphiles were characterized by means of nuclear magnetic resonance spectroscopy (NMR) and gel permeation chromatography (GPC). Atomic force microscopy (AFM) showed that the POSS-capped PNIPAAm amphiphiles in bulk displayed microphase-separated morphologies. In aqueous solutions, the POSS-capped PNIPAAm amphiphiles were self-assembled into micelle-like aggregates as evidenced by dynamic light scattering (DLS) and transmission election microscopy (TEM). It was found that the sizes of the self-organized nanoobjects decreased with increasing the lengths of PNIPAAm chains. By means of UV–vis spectroscopy, the lower critical solution temperature (LCST) behavior of the organic–inorganic amphiphiles in aqueous solution was investigated and the LCSTs of the organic–inorganic amphiphiles decreased with increasing the percentage of POSS termini. It is noted that the self-assembly behavior of the POSS-capped PNIPAAm in aqueous solutions exerted the significant restriction on the macromolecular conformation alteration of PNIPAAm chains while the coil-to-globule collapse occurred.
- Published
- 2012
33. Poly(ethylene oxide)-grafted poly(N-isopropylacrylamide) networks: Preparation, characterization and rapid deswelling and reswelling behavior of hydrogels
- Author
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Sixun Zheng and Yaochen Zheng
- Subjects
Polymers and Plastics ,Ethylene oxide ,General Chemical Engineering ,Oxide ,Chain transfer ,General Chemistry ,Raft ,Biochemistry ,chemistry.chemical_compound ,chemistry ,Polymerization ,Polymer chemistry ,Self-healing hydrogels ,Materials Chemistry ,Poly(N-isopropylacrylamide) ,Copolymer ,Environmental Chemistry - Abstract
Poly(ethylene oxide)-grafted poly(N-isopropylacrylamide) networks (PNIPAAm-g-PEO) were prepared via the reversible addition–fragmentation chain transfer polymerization (RAFT) of N-isopropylacrylamide with trithiocarbonate-terminated poly(ethylene oxide) and N,N′-methylenebisacrylamide as the chain transfer agent and the crosslinking agent, respectively. It was found that the PNIPAAm-g-PEO copolymer networks were microphase-separated and that PEO microdomains were dispersed in the PNIPAAm matrix. The hydrogel behavior of the PNIPAAm-g-PEO networks was investigated using swelling, deswelling and reswelling tests. The PNIPAAm-g-PEO hydrogels displayed faster responses to external temperature changes than did the control PNIPAAm hydrogel.
- Published
- 2012
34. Synthesis and Self-Assembly Behavior of Organic-Inorganic Poly(ethylene oxide)-block -Poly(MA POSS)-block -Poly(N -isopropylacrylamide) Triblock Copolymers
- Author
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Sixun Zheng, Lei Wang, Rentong Yu, and Yaochen Zheng
- Subjects
Cloud point ,Materials science ,Polymers and Plastics ,Atom-transfer radical-polymerization ,Organic Chemistry ,Condensed Matter Physics ,chemistry.chemical_compound ,Differential scanning calorimetry ,chemistry ,Dynamic light scattering ,Amphiphile ,Polymer chemistry ,Materials Chemistry ,Poly(N-isopropylacrylamide) ,Copolymer ,Self-assembly ,Physical and Theoretical Chemistry - Abstract
In this work, the synthesis of 3-methacryloxypropylheptaphenyl POSS, a new POSS macromer (denoted MA-POSS) is reported. The POSS macromer is used to synthesize PEO-b-P(MA-POSS)-b-PNIPAAm triblock copolymers via sequential atom transfer radical polymerization (ATRP). The organic-inorganic, amphiphilic and thermoresponsive ABC triblock copolymers are characterized by means of nuclear magnetic resonance spectroscopy (NMR) and gel permeation chromatography (GPC). Differential scanning calorimetry (DSC) and atomic force microscopy (AFM) show that the hybrid ABC triblock copolymers are microphase-separated in bulk. Cloud point measurements show that the effect of the hydrophiphilic block (i.e. PEO) on the LCSTs is more pronounced than the hydrophobic block (i.e. P(MA-POSS)). Both transmission electron microscopy (TEM) and dynamic light scattering (DLS) show that all the triblock copolymers can be self-organized into micellar aggregates in aqueous solutions. The sizes of the micellar aggregates can be modulated by changing the temperature. The temperature-tunable self-assembly behavior is interpreted using a combination of the highly hydrophobicity of P(MA-POSS), the water-solubility of PEO and the thermoresponsive property of PNIPAAm in the triblock copolymers.
- Published
- 2012
35. A heterogeneous lattice gas model for simulating pedestrian evacuation
- Author
-
Xiwei Guo, Junhong Wei, Yaochen Zheng, and Jianqiao Chen
- Subjects
Computer Science::Multiagent Systems ,Statistics and Probability ,Nonlinear system ,Computer science ,Lattice (order) ,Local population ,Statistical physics ,Pedestrian ,Nonlinear Sciences::Cellular Automata and Lattice Gases ,Condensed Matter Physics ,Cellular automaton - Abstract
a b s t r a c t Based on the cellular automata method (CA model) and the mobile lattice gas model (MLG model), we have developed a heterogeneous lattice gas model for simulating pedestrian evacuation processes in an emergency. A local population density concept is introduced first. The update rule in the new model depends on the local population density and the exit crowded degree factor. The drift D, which is one of the key parameters influencing the evacuation process, is allowed to change according to the local population density of the pedestrians. Interactions including attraction, repulsion, and friction between every two pedestrians and those between a pedestrian and the building wall are described by a nonlinear function of the corresponding distance, and the repulsion forces increase sharply as the distances get small. A critical force of injury is introduced into the model, and its effects on the evacuation process are investigated. The model proposed has heterogeneous features as compared to the MLG model or the basic CA model. Numerical examples show that the model proposed can capture the basic features of pedestrian evacuation, such as clogging and arching phenomena.
- Published
- 2012
36. Hetero-Functional Polymers with Alternating Hydroxyl and Epoxy Groups Synthesized by Thiol-yne Click (co)Polymerization
- Author
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Zhengguo Gao, Wenzuo Li, Bingfei Yan, Yaochen Zheng, Qian Zhang, and Fucun Li
- Subjects
chemistry.chemical_classification ,Polymers and Plastics ,Chemistry ,Organic Chemistry ,02 engineering and technology ,Epoxy ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,Polymerization ,visual_art ,Polymer chemistry ,Materials Chemistry ,Thiol ,visual_art.visual_art_medium ,Physical and Theoretical Chemistry ,Functional polymers ,0210 nano-technology - Published
- 2018
37. ChemInform Abstract: Hyperbranched Polymers: Advances from Synthesis to Applications
- Author
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Chao Gao, Zhulin Weng, Yaochen Zheng, and Sipei Li
- Subjects
chemistry.chemical_compound ,Monomer ,Polymerization ,chemistry ,Supramolecular chemistry ,Surface modification ,Nanotechnology ,General Medicine ,Hybrid material ,Cycloaddition ,Ene reaction ,Macromolecule - Abstract
Hyperbranched polymers (HPs) are highly branched three-dimensional (3D) macromolecules. Their globular and dendritic architectures endow them with unique structures and properties such as abundant functional groups, intramolecular cavities, low viscosity, and high solubility. HPs can be facilely synthesized via a one-pot polymerization of traditional small molecular monomers or emerging macromonomers. The great development in synthetic strategies, from click polymerization (i.e., copper-catalyzed azide–alkyne cycloaddition, metal-free azide–alkyne cycloaddition, strain-promoted azide–alkyne cycloaddition, thiol–ene/yne addition, Diels–Alder cycloaddition, Menschutkin reaction, and aza-Michael addition) to recently reported multicomponent reactions, gives rise to diverse HPs with desirable functional/hetero-functional groups and topologies such as segmented or sequential ones. Benefiting from tailorable structures and correspondingly special properties, the achieved HPs have been widely applied in various fields such as light-emitting materials, nanoscience and technology, supramolecular chemistry, biomaterials, hybrid materials and composites, coatings, adhesives, and modifiers. In this review, we mainly focus on the progress in the structural control, synthesis, functionalization, and potential applications of both conventional and segmented HPs reported over the last decade.
- Published
- 2015
38. Water soluble octa-functionalized POSS: all-click chemistry synthesis and efficient host-guest encapsulation
- Author
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Jin Han, Shuai Zheng, Tiannan Hu, Yaochen Zheng, Aijin Tang, Chao Gao, and Sipei Li
- Subjects
chemistry.chemical_classification ,Metals and Alloys ,General Chemistry ,Catalysis ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Encapsulation (networking) ,Water soluble ,chemistry ,Amphiphile ,Materials Chemistry ,Ceramics and Composites ,Click chemistry ,Organic chemistry ,Alkyl - Abstract
A series of water soluble octa-functionalized POSSs were facilely synthesized via thiol-ene and Menschutkin click chemistry. Among them, octa-alkynyl POSS further reacted with azide-terminal alkyl long chains, resulting in a well-defined, amphiphilic octopus-like POSS. For the first time it was used for host-guest encapsulation and it exhibited an ultrahigh loading capability.
- Published
- 2014
39. Sequentially Hetero-functional, Topological Polymers by Step-growth Thiol-yne Approach
- Author
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Yaochen Zheng, Sipei Li, Bo Zhao, Jin Han, Chao Gao, and Yuanchao Zhang
- Subjects
Biomimetic materials ,Free Radicals ,Computer science ,Polymers ,Bioinformatics ,Article ,Catalysis ,Polymerization ,chemistry.chemical_compound ,Biomimetic Materials ,Sulfhydryl Compounds ,chemistry.chemical_classification ,Multidisciplinary ,Polymer ,DNA ,Combinatorial chemistry ,Solvent ,Monomer ,chemistry ,Yield (chemistry) ,Alkynes ,Thiol ,Solvents ,Functional polymers - Abstract
Sequence-controlled polymers (SCPs) such as DNA and proteins play an important role in biology. Many efforts have been devoted to synthesize SCPs in the past half a century. However, to our knowledge, the artificial sequences containing independently functional groups have never been reported. Here, we present a facile and scalable approach based on radical-initiated step-growth polymerization to synthesize sequence-controlled functional polymers (SCFPs) with various topologies, covering from linear to random and hyperbranched polymers. The functional groups, such as OH/NH2, OH/COOH, and NH2/N3, alternately arranged along the chain, which were further selectively functionalized to achieve DNA-mimic and hetero-multifunctional SCPs. This user-friendly strategy exhibits advantages of commercially available monomers, catalyst-free process, fast reaction, high yield and water solvent, opening a general approach to facile and scalable synthesis of SCFPs.
- Published
- 2014
40. Synthesis, Dye Encapsulation, and Highly Efficient Colouring Application of Amphiphilic Hyperbranched Polymers
- Author
-
Zhulin Weng, B Yaochen Zheng, C Aijin Tang, and Chao Gao
- Subjects
chemistry.chemical_classification ,chemistry.chemical_compound ,Membrane ,chemistry ,Polymerization ,Propargyl ,Polymer chemistry ,Amphiphile ,Methyl orange ,Click chemistry ,General Chemistry ,Polymer ,Methacrylate - Abstract
A novel kind of amphiphilic hyperbranched polymer (AHP), poly(2-(dimethylamino)ethyl methacrylate)-co-polystyrene (HPTAM-co-PS), was synthesized via the combination of reversible addition–fragmentation chain-transfer polymerization and self-condensing vinyl polymerization (RAFT-SCVP). HPTAM-co-PS was functionalized via the highly efficient Menschutkin click reaction, resulting in hyperbranched poly(propargyl quaternary ammonium methacrylate)-co-polystyrene (HPPrAM-co-PS) with a hydrophilic quaternary ammonium salt core and hydrophobic PS shell. The average numbers of dye molecules trapped by each molecule of HPPrAM-co-PS (24.2 kDa) were 24.1 for methyl orange (MO), 22.0 for fluorescein sodium (FS), 24.2 for rose bengal (RB), and 238.4 for Congo red (CR). The polymer–dye complexes show excellent colouring effects for both PS and poly(styrene-b-butadiene-b-styrene) (SBS) membranes; the colour of the membrane containing AHP is very stable and uniform. Our work opens an avenue for the design of efficient dye-colouring additives and for the application of hyperbranched polymers in the field of polymer colouring.
- Published
- 2014
41. Sequentially Hetero-functional, Topological Polymers by Step-growth Thiol-yne Approach.
- Author
-
Jin Han, Yaochen Zheng, Bo Zhao, Sipei Li, Yuanchao Zhang, and Chao Gao
- Subjects
- *
LIVING polymerization , *POLYCONDENSATION , *MONOMERS , *THIOLS , *POLYMERS , *DNA - Abstract
Sequence-controlled polymers (SCPs) such as DNA and proteins play an important role in biology. Many efforts have been devoted to synthesize SCPs in the past half a century. However, to our knowledge, the artificial sequences containing independently functional groups have never been reported. Here, we present a facile and scalable approach based on radical-initiated step-growth polymerization to synthesize sequence-controlled functional polymers (SCFPs) with various topologies, covering from linear to random and hyperbranched polymers. The functional groups, such as OH/NH2, OH/COOH, and NH2/N3, alternately arranged along the chain, which were further selectively functionalized to achieve DNA-mimic and hetero-multifunctional SCPs. This user-friendly strategy exhibits advantages of commercially available monomers, catalyst-free process, fast reaction, high yield and water solvent, opening a general approach to facile and scalable synthesis of SCFPs. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
42. A facile strategy for the functionalization of poly[cyclotriphosphazene-co-(4,4′-sulfonyldiphenol)] materials.
- Author
-
Wei Liu, Jing Jin, Xiaobin Huang, Yaochen Zheng, Jiawei Zhang, Jianwei Fu, Yawen Huang, and Xiaozhen Tang
- Subjects
NANOTUBES ,NANOFIBERS ,MICROSPHERES ,THERMAL properties ,POLYMERIZATION ,PHYSICAL & theoretical chemistry - Abstract
Recently, a new type of phosphazenecontaining material, polycyclotriphosphazeneco4,4′sulfonyldiphenol PZS, was successfully prepared. PZS materials including PZS nanotubes, PZS nanofibers and PZS microspheres show excellent thermal stability, biocompatibility and biodegradability. Moreover, PZScontaining materials such as silver nanowirePZS, carbon nanotubePZS and Fe3O4PZS nanotubes have also been prepared. Therefore, we explored a specific method for the functionalization of these PZS and PZScontaining materials to expand their scope of application. As a model of various PZS and PZScontaining materials, PZS microspheres PZSMs were functionalized via surfaceinitiated atom transfer radical polymerization ATRP. Polymerization of styrene occurred at surface sites covalently derivatized with ATRP initiators to form PZSM–polystyrene. The numberaverage molecular weight Mn of grafted polymer chains could be well controlled. Furthermore, PZSM–polystyrene was still active for further block copolymerization of methyl methacrylate. Both styrene and acrylatetype monomers could be directly polymerized or block copolymerized from the surface of PZS and PZScontaining materials using surfaceinitiated ATRP. Mnof grafted polymer chains could be well controlled. This facile strategy could pave the way for a wider range of applications of these materials. Copyright © 2010 Society of Chemical Industry [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
43. Water soluble octa-functionalized POSS: all-click chemistry synthesis and efficient host--guest encapsulation.
- Author
-
Shuai Zheng, Sipei Li, Tiannan Hu, Aijin Tang, Chao Gao, Jin Han, and Yaochen Zheng
- Subjects
THIOLS ,AZIDES ,ALKYNES ,NUCLEAR magnetic resonance ,ORGANIC light emitting diodes ,SUPRAMOLECULAR chemistry - Abstract
A series of water soluble octa-functionalized POSSs were facilely synthesized via thiol--ene and Menschutkin click chemistry. Among them, octa-alkynyl POSS further reacted with azide-terminal alkyl long chains, resulting in a well-defined, amphiphilic octopus-like POSS. For the first time it was used for host--guest encapsulation and it exhibited an ultrahigh loading capability. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
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