COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2024
·
IF 4.9
Hui Jiang,Xiaoyan Liu,Ying Xu,Yongying Jia
As a complex component of crude oil, asphaltenes determine the stability of emulsion . However, the mechanism of asphaltenes stabilize emulsion is still insufficient recognition due to the complexity of the molecular structure of asphaltenes. In this paper, the experiments and dissipative particle dynamics simulations were used to study the interfacial properties of asphaltenes. The adsorption of asphaltenes at the oil–water interface was studied by interfacial tension (IFT) experiments. A realistic molecular structure of asphaltene was constructed on the results of the characterization of the asphaltenes. The effects of asphaltenes concentration, temperature, and shear on the formation and stability of emulsion based on this molecular structure were investigated by simulations. The results show that the IFT decreases as asphaltenes concentration increases, while the droplet size of the emulsion decreases and becomes more uniformly distributed. Increasing the temperature enhances the interfacial activity of the asphaltenes, but also promotes its dissolution in the oil phase, which has a negative effect on reducing the IFT value and the stability of the emulsion. As the shear rate increases , the configuration of the emulsion changes from droplets to ellipsoids and rods, and the structure of the interfacial film is disrupted. This work provides useful insights into the mechanisms of asphaltenes concentration, temperature, and shear on the stability of the emulsion.
研究领域:
石油化学
·
胶体与界面科学
·
流体力学
·
分子模拟
·
能源工程
✓ 已验证
DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2019
·
IF 4.561
Xiao-Qian Wei,Wan-Ju Zhang,Lu Lai,Ping Mei,Li-Mei Wu,Yan-Qun Wang
The effects of cationic surfactants on the properties of Pickering emulsions stabilized by silica nanoparticles (nano-SiO 2 ) were investigated. The zeta potential , three-phase contact angle ( θ ), and dynamic interfacial tension (DIT) were measured to analyze the interaction between hydrophilic nano-SiO 2 and four different cationic surfactants (i.e., dodecyltrimethylammonium bromide [DTAB], bis-quaternary ammonium salts [BQAS-12], multiple quaternary ammonium salts [MQAS-12], and dimethyldioctadecylammonium bromide [DDAB-18]). All these surfactants can naturally improve the stability of Pickering emulsions induced by hydrophilic nano-SiO 2 . The nano-SiO 2 /MQAS-12 mixtures exhibited the best ability to stabilize the O/W emulsions, followed by nano-SiO 2 /BQAS-12 mixtures. The nano-SiO 2 /DDAB-18 mixtures can induce emulsion inversion from O/W to W/O. All emulsions exhibited excellent salt tolerance and acid-base resistance properties. Determining the zeta potential showed that nano-SiO 2 had the highest negative charge at the pH of 9.5. Thus, the surfactant molecules can be adsorbed remarkably on the nano-SiO 2 surface. Modification with different cationic surfactants can significantly increase the θ value of nano-SiO 2 , but the bilayers for DTAB-12, BQAS-12, and MQAS-12, except for DDAB-18, were adsorbed. DIT curves indicated that competitive adsorption of the surfactants occurred between the oil/water interface and nano-SiO 2 surface. The competitive adsorption of MQAS-12 was stronger than those of BQAS-12 and DTAB-12. The nano-SiO 2 /DDAB-18 mixture had an apparent induction region and required a considerable amount of time to reach equilibrium. The modified nano-SiO 2 was also not adsorbed in the oil/water interface spontaneously, which may be due to the large size of particles compared with small surfactant molecules.
研究领域:
胶体与界面化学
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纳米材料科学
·
乳液工程
·
物理化学
·
表面科学
✓ 已验证
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2018
·
IF 4.439
Haihua Wang,Bei Li,Guiqiang Fei,Yiding Shen,Ke Zhu
We reported herein the synthesis of block copolymers and their application in the in-situ emulsion polymerization of waterborne poly (urethane-acrylate) (WPUA) nanoemulsions based on phase inversion process. The polymerizable surfmers containing terminal unsaturated double bonds (MSA-r) were successfully synthesized via catalytic chain transfer polymerization (CCTP). Random copolymer (MSA-t) prepared through radical polymerization was utilized as control. The structure, surface tension and aggregation behavior of surfmers were characterized. The phase inversion, formation and stability of WPUA nanoemulsions were systematically investigated. Effects of MSA-r surfmer content and BMA/MMA ratio on the water resistance and thermal stability of the corresponding films were also discussed. It was found that the phase inversion mechanism of PUA prepolymer in the presence of MSA-r surfmers is different from conventional polyurethane prepolymer. The addition of MSA-r and MSA-t surfmers alters the rheological behaviors of PUA prepolymer via PUA-surfmer interactions, as well as the phase inversion process. Compared with WPUA/MSA-t emulsion, WPUA/MSA-r nanoemulsion displayed improved stability at higher solid content. The minimum particle size of WPUA/MSA-r nanoemulsion was 88.7 nm and kept almost constant after 12-month storage, while the particle size of WPUA/MSA-t emulsion was 131.3 nm and increased to 178.9 nm. Moreover, the WPUA/MSA-r film possessed improved water resistance and thermal stability.
研究领域:
高分子化学
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胶体与界面科学
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材料化学
·
纳米材料
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功能高分子
·
水性涂料
·
聚合物乳液
✓ 已验证
DOI
高影响因子
MACROMOLECULAR CHEMISTRY AND PHYSICS
·
2019
·Vol. 220
·期 4
·1800395
·
IF 2.622
Xue Wang,Linlin Chen,Guanqing Sun,Ren Liu
Hollow microcapsules with controlled mechanical strength are obtained from Pickering emulsion templates. The shell of the hollow microcapsules comprising UV-curable resin and reactive silica nanoparticles enables tuning of the mechanical properties in a controlled manner. The results show that the particle stabilizer can be packed regularly on the oil–water interface and the shell thickness of microcapsules can be increased to 1–2 µm compared with traditional preparation methods. Hollow particles with thicker walls can prevent collapse and breakage. In this work, a nanoindentation device is used to measure the mechanical properties of hollow particles, and the results show a clear trend of reduced modulus and hardness decreases with increasing ratio of prepolymers in the reaction mixture. When the mass of PUA varies from 10% to 30%, the hardness decreases from 0.09 to 0.04 GPa, while the reduced modulus decreases from 0.17 to 0.06 GPa. The control of mechanical properties of the microcapsule can enhance its uses in conventional areas as well as in new fields such as precise micro force sensors etc.
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 APPLIED POLYMER SCIENCE
·
2018
·Vol. 136
·期 17
·47419
·
IF 1.901
Xiao Wang,Xiufeng Hao,Dan Chang,Chongyi Zhu,Lili Chen,Alideertu Dong,Ge Gao
N -halamine-based antibacterial agents have high efficiency and rechargeable antibacterial properties. However, their applications are limited due to their complex synthetic process and fuzzy antibacterial mechanism. In this study, a novel N -halamine antibacterial polymer was synthesized by inverse emulsion polymerization and characterized by Fourier transform infrared, nuclear magnetic resonance, scanning electron microscopy, thermogravimetric analysis, and X-ray photoelectron spectroscopy. Due to the difficulty of purification, most of the subjects studied previously were hydrophobic polymers, while little research on hydrophilic polymers. In this experiment, this difficulty was overcome by controlling the dosage of sodium hypochlorite and methods of dialysis. Because of the complex cell structure of Gram-negative bacteria, it is difficult for N -halamines to release the oxidizing chlorine into the cell. However, the hydrophilic N -halamines can solve this problem, which showed a stronger antibacterial effect on Gram-negative Escherichia coli synthesized in this study. In addition, the particle size and hydrophilic property of the polymer were changed by changing the amount of initiator, and the differences in their antibacterial properties were studied. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 47419.
研究领域:
材料科学
·
微生物学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2012
·Vol. 2
·期 12
·5403-5410
·
IF 0
Qinghua Liang,Yao Shi,Wangjing Ma,Zhi Li,Xinmin Yang
Uniform square-like BaFBr:Eu2+ microplates were successfully fabricated via a simple water/oil emulsion method. Various characterization techniques such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, Scanning electron microscopy (SEM) and Transition electron microscopy (TEM) were employed to examine the phase, size, morphology, and structure of the products. It was found that the morphology and size of products were strongly dependent on the reaction parameters, such as the ratio of reactants, the reaction time and the reaction temperature. The length and thickness of these square-like BaFBr:Eu2+ microplates can be tuned by adjusting the reaction time and temperature. Well-dispersed cuboctahedron and corner cut cuboid-like BaFBr:Eu2+ particles were produced when the reaction temperature was increased above 60 °C. A possible formation mechanism of the products was discussed based on the time and temperature-dependent experimental results. The optical properties were characterized by photoluminescence (PL) spectroscopy as well as kinetic decay. Eu2+-doped dependent luminescent intensity was investigated in detail. The prepared BaFBr:Eu2+ phosphors are considered promising materials for fluorescent applications.
研究领域:
材料科学
·
无机化学
·
纳米技术
·
光学材料
·
功能材料
✓ 已验证
DOI
FOOD HYDROCOLLOIDS
·
2017
·
IF 4.747
Enmin Chen,Lianqi Cao,David Julian McClements,Shilin Liu,Bin Li,Yan Li
The impact of incorporating different levels of cinnamaldehyde (CA) into the oil phase used to prepare whey protein isolate (WPI)-stabilized nanoemulsions was investigated. Stable nanoemulsions could not be formed by pure CA, which was attributed to gravitational separation, but they could be formed from mixtures of CA and triglycerides. The mean particle diameter produced by homogenization decreased with increasing CA, which was attributed to the reduction of oil phase interfacial tension and viscosity. CA enhanced the physical stability of the nanoemulsions to salt addition (0–500 mM) and thermal processing (30–90 °C), but could not prevent droplet flocculation near the protein's isoelectric point (around pH 5). SDS-PAGE and surface load measurements indicated that more protein accumulated at the droplet surfaces in the presence of CA, which was attributed to interfacial crosslinking. CA may therefore be a useful means of modulating the physicochemical properties of protein-stabilized nanoemulsions.
研究领域:
食品科学
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胶体与界面化学
·
蛋白质功能特性
·
递送系统
·
食品纳米技术
✓ 已验证
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2018
·
IF 2.829
Rongli Zhang,Jingjing Lv,Cuige Zhang,Renchun Yang,Xingchen Sun,Bo Song,Ching-Ping Wong
A new kind of dopamine modified alginate colloid particles (DA-ALG CPs) was prepared via the direct chemical self-assembly triggered by the amidation reaction between dopamine and alginate in aqueous solution. The structure and morphology of the DA-ALG CPs were characterized by infrared spectroscopy , Zeta PALS and scanning electron microscope . The prepared DA-ALG CPs were then used as particulate emulsifier to prepare Pickering emulsions . The properties of the emulsion were characterized by optical microscope . The results revealed that the prepared DA-ALG CPs exhibited good emulsifying property at a wide pH value range, which will endow the potential application of the Pickering emulsions stabilized by DA-ALG CPs in food and biological medicine fields.
研究领域:
高分子材料学
·
胶体与界面化学
·
食品科学
·
生物医学工程
·
药物递送
·
纳米医学
✓ 已验证
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2023
·
IF 5.2
Hao Wu,Tianyi Jiang,Wenlong Wu,Shanguo Zhang,Ming Li,Jingzhuo Zhou,Mengya Zhu,Juzheng Chen,Ziyong Li,Yang Lu,Hongyuan Jiang
Water-in-oil-in-water (W/O/W) double emulsion droplets are a typical colloidal system applied in various practical fields. However, certain high-specification applications necessitate exact geometric homogeneity in terms of both shell diameter and thickness. Despite achieving uniformity in shell diameter, on-chip microfluidic emulsification always leads to an eccentric phenomenon due to innate density differences of the droplet solution. At the same time, the current regulation methods have multiple limitations, including their applicability, regulatory scope, and objective restrictions. Herein, we propose an off-chip osmosis-induced hydrodynamic method to accurately regulate the eccentricity of W/O/W double emulsion droplets. The rational selection of hypertonic osmosis can energize the droplets and induce inward transmembrane water flux. This flow helps to reposition the droplet core to align concentrically with the shell, regardless of the initial dimension and eccentricity of the droplets. As the osmotic induction reduces due to the dilution of the inner solute molar concentration , the optimal droplet configuration can be achieved when osmosis-induced hydrodynamic regulation sufficiently counteracts the adverse effects of droplet solution density difference. The microcapsules can thus be produced by instant UV polymerization of the regulated double emulsion droplets, and the silica microspheres with fine geometric homogeneity can be prepared through further heat treatment, which is expected to meet the stringent morphological requirements in practical applications.
研究领域:
胶体与界面化学
·
微流控技术
·
生物材料
·
药物递送系统
·
高分子科学
✓ 已验证
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2017
·Vol. 134
·期 35
·45258
·
IF 1.86
Jie Shen,Jian-wu Sun,Yang Hu,Cheng-you Kan
Polysiloxane/polyacrylate (PSi/PA) core/shell latexes are fabricated, and the particle morphology, the film structure, as well as the properties of the latex films are investigated by comparing with blend latexes, and the relationship between structure and property is proposed. Results indicate that the structure and property of the latex films heavily depend on the particle morphology. The sea–island latex films with uniform distribution of PSi phases can be formed from the PSi/PA core/shell latexes, and with the mass ratio from 1:1 to 1:4, their tensile strength and elongation at break are close to the pure PA latex film, while the elastic recovery and water vapor permeability improve notably. It is found that the phase segregation occurs in the blend latex films, and although the blend latex films provide better water vapor breathability, their mechanical properties sacrifice obviously. Therefore, the various properties must be balanced for practical applications and the core/shell latexes are competitive for meeting the balanced requirements. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45258.
研究领域:
高分子科学
·
材料化学
·
功能材料
·
胶体与界面化学
·
薄膜材料
✓ 已验证
DOI
高影响因子
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
·
2021
·
IF 3.995
Jianhua Zhou,Hong Li,Yannan Li,Xiang Li
Cellulose nanocrystals (CNCs) were modified using an amphiphilic triblock copolymer [poly(2-(dimethylamino) ethyl methacrylate)- b -poly(glycidyl methacrylate)- b -poly(2,2,3,4,4,4-hexafluorobutyl acrylate) (PDMAEMA- b -PGMA- b -PHFBA)] bearing epoxy functionalities located in middle segment of PGMA, which were used to react with the hydroxyl groups on the surface of the CNCs. The triblock copolymer was synthesized via a reversible addition fragmentation chain transfer (RAFT) polymerization reaction between 2-(dimethylamino) ethyl methacrylate, glycidyl methacrylate and 2,2,3,4,4,4-hexafluorobutyl acrylate, and characterized using 1 H-NMR spectroscopy and size exclusion chromatography (SEC). The successful modification of the CNCs was demonstrated by means of FT-IR, TGA , TEM , XRD and XPS . In addition, the surface properties of the modified CNCs were studied using water contact angle and surface tension studies. When compared with the pristine CNCs, the modified CNCs exhibited a higher contact angle and lower surface tension. Good dispersion of the modified CNCs was observed in different polar solvents, such as water, THF, DMF , CHCl 3 and toluene. The modified CNCs exhibited pH responsive properties, which were measured using dynamic light scattering (DLS). In addition, the stability of Pickering emulsions stabilized by PDMAEMA- g -CNC- g -PHFBA decreased with time or increasing pH. The droplet size increased gradually upon increasing the pH. This work provides a method to design sophisticated CNC-based materials, which benefit from both the intrinsic properties of the CNCs and the new characteristics conferred by the multifunctional grafted chains.
研究领域:
高分子化学
·
纳米材料科学
·
胶体与界面化学
·
生物基功能材料
·
智能响应材料
✓ 已验证
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2018
·
IF 5.091
Zanru Guo,Hongjian Gu,Qiang Chen,Zhanfeng He,Wenyuan Xu,Jiali Zhang,Yongxin Liu,Leyan Xiong,Longzhen Zheng,Yujun Feng
Hypothesis The effective separation and recovery of oils from water is important for the protections of ecosystems and the environment. Polymeric porous monoliths have been demonstrated as attractive absorbents for oil/water separation. However, the recyclability was mainly realized by squeezing, combustion, or centrifugation, which may restrict in elastic materials, destroy the adsorbates or need special apparatus. Thus it is desirable to developing monoliths with controllable oil absorption and desorption. Experiments A series of “smart” monoliths with pH-induced switchable wettability were fabricated by high internal phase emulsion (HIPE) polymerization and epoxide ring-opening for the incorporation of amine groups. The resultant monoliths and their wettabilities were examined using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), nitrogen adsorption/desorption and contact angle analysis, respectively. The oil separation efficiency and recyclability were evaluated. Findings The monoliths with macroporous structure can undergo switchable wettability under reversible pH stimulation. As an absorbent, the monoliths not only separated and recovered organic solvents and oils (including crude oil) from aqueous mixtures through a reversible and recyclable absorption and desorption process upon alternating the pH between 7.0 and 1.0, but also continuously expulsed oils from water surfaces in a continuous manner with the aid of external driving pressures. Moreover, the monoliths also allowed the effective separation of surfactant-free and surfactant-stabilized oil-in-water emulsions with high separation efficiency.
研究领域:
环境科学
·
高分子材料
·
分离科学
·
界面化学
·
功能材料
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）