LANGMUIR
·
2024
·
IF 3.7
Weidong Fang,Zhi Tao,Haiwang Li,Yuqian Ma,Shuai Yin,Tiantong Xu,Teckneng Wong,Yi Huang
Emulsions have been applied in a number of industries such as pharmaceutics, cosmetics, and food, which are also of great scientific interest. Although aqueous emulsions are commonly used in our daily life, oil-in-oil (o/o) emulsions also play an irreplaceable role in view of their unique physics and complementary applications. In this paper, we investigate typical behaviors of organic droplets surrounded by organic medium (o/o emulsions) with different functional groups controlled by the AC electric field. Droplet behaviors can be catalogued into five types: namely, “no effect”, “movement”, “deformation”, “interface rupture”, and “disorder”. We identify the key dimensionless number Wee·Ca, combined with the channel geometry, for characterizing the typical behaviors in silicon oil/1,6-hexanediol diacrylate and mineral oil/1,6-hexanediol diacrylate emulsions. Unlike aqueous emulsion, the Maxwell–Wagner relaxation inhibits the electric effect and leads to an effective frequency, ranging from 0.5 to 3 kHz. The increasing viscosity of the droplet facilitates the escalation by promoting the shearing effect under the same flow conditions. Ethylene glycol droplets primarily show the efficient coalescence even at a low Wee·Ca, which is attributed to the attraction of free charges induced by the increasing conductivity. In 1,6-hexanediol diacrylate/silicon oil emulsion, the droplet tends to form a liquid film that expands into the entire channel due to the affinity of the droplet to the channel wall. A variety of elongated columns are observed to oscillate between the electrodes at high voltages. These findings can contribute to understanding the electrohydrodynamic physics in o/o emulsion and controlling droplet behaviors in a fast response, programmable, and high-throughput way. We expect that this droplet manipulation technology can be widely adopted in a broad range of chemical synthesis and biological and material science.
研究领域:
物理学
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化学工程
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MACROMOLECULES
·
2015
·
IF 5.8
Shuang Chen,Dongxue Chen,Min Lu,Xin Zhang,He Li,Xiaoyan Zhang,Xiaoming Yang,Xiaohong Li,Yingfeng Tu,Christopher Y. Li
To achieve high refractive index polymers (HRIPs), we report here the design and synthesis of four fullerene polyesters (P1–P4), based on the conjunction effect from the high refractive index polyester backbones and pendent fullerene side chains. At sodium D line (589 nm), the refractive indices of the fullerene polyesters are all higher than 1.80, the used believed upper limitation of intrinsic organic polymers. To achieve precise pendent fullerene structure, these polyesters were synthesized via condensation polymerization by a fullerene diol with different aromatic diacyl chlorides, where the diacyl chlorides with high molar refraction increment value moiety were selected by molecular tailoring according to Lorentz–Lorenz equation. The fullerene polyesters are characterized by gel permeation chromatography (GPC), ultraviolet–visible (UV–vis) spectroscopy, and the molecular weights are obtained by a quantitative NMR technique with end-group estimation. The formation of fullerene polyesters is also proved by the 1H DOSY NMR results. These fullerene polyesters have good solubility in some common organic solvents, good thermal stability up to 320 °C, and film forming ability. All these films have good adhesion to glass sheets with relatively good hardness. Among them, the thiophene-containing fullerene polyesters (P1) has the best optical properties, with the highest refractive index value (1.86 at 589 nm), one of the highest value for intrinsic organic polymers, and the highest Abbe number (27.9).
研究领域:
材料科学
·
有机化学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2023
·
IF 6.7
Yihan Wang,Xiang Chu,Hongrui Zhang,Cheng Yan,Guo Tian,Weiqing Yang,Xiangrong Chen,Haitao Zhang
Conjugated polymers promise extremely-high theoretical supercapacitance to develop large capacitive storage devices. Existing conjugated polymers commonly realize their < 20% supercapacitance due to inferior electronic and electrochemical activities. Here we report hyper-conjugated effect to minimize energy level difference and carrier migration barrier in copolymerized polyaniline (PANI), a typical supercapacitive material. The hyper-conjugated effect efficiently promotes the elongation of conjugation system and the delocalization of π electrons. The largely increased number of free carriers in combination with the expanded range of carrier mobility guarantee 800% increments in electrical conductivity. Tests of symmetric supercapacitors with hyper-conjugated PANI show a high specific capacitance of 512 F g −1 , excellent rate-capability and long-term cyclability. This work paves the way for designing conjugated polymers with remarkable electronic and electrochemical properties.
研究领域:
材料科学
·
电化学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY
·
2021
·
IF 4.291
Miao Yao,Shaohui Liu,Chen Huang,Jun Nie,Yong He
Five ester derivatives from hydroxyalkyl of 2-hydroxy-2-methyl-1-phenyl propanone, one of the most successfully applied α-hydroxyalkyl acetophenone photoinitiators, are synthesized. From the spectroscopy results and theory calculation, it is proved that the much lower photocleavage rates of the directly linked unsaturated ester derivatives are due to that the strong electron withdrawing effect of carbonyl increase the bond strength between the benzoyl and quaternary carbon and the effective energy transfer from benzoyl to double bond because of the existence of p-σ-π hyperconjugation, which consequently decreased their initiating ability. Excitingly, simple introduction of two-methylene spacer between the carbonyl and alkoxyl can effectively block the hyperconjugation and significantly increase the photocleavage rate up to the same level of their mother commercial photoinitiator, which can open a gate for design of new high efficiency and polymerizable type I photoinitiators.
研究领域:
有机化学
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材料科学
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光化学
✓ 已验证
产品关联
DOI
高影响因子
Materials Research Express
·
2021
·Vol. 8
·期 6
·065304
·
IF 1.62
Nianxin Jiang,Zhengfa Zhou,Weibing Xu,Haihong Ma,Fengmei Ren
Boron-containing phenyl silicone oil (BCPSO) with terminal boronic hydroxyl groups was synthesized by acid-catalyzed balance condensation polymerization using phenylboric acid, dimethyldichlorosilane and diphenyldichlorosilane as raw materials. The structure of BCPSO was characterized by 1H, 13C and 29Si nuclear magnetic resonance (NMR) and Fourier transform infrared spectrometry (FTIR). The thermal degradation behavior of BCPSO was tested by thermogravimetry-Fourier transform infrared spectrometry (TG-FTIR) analysis. The TG-FTIR results indicated that thermal decomposition of BCPSO had significant hysteresis over that of phenyl silicone oil. The empty electron orbital of boron atom could accept electron of peroxide free radical to generate conjugation effect at initial degradation stage of BCPSO, and this phenomenon was confirmed by 11B NMR, FTIR and Raman spectroscopies. As a result, temporarily stable intermediate was formed which increased the heat resistant of BCPSO.
研究领域:
材料科学
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化学工程
✓ 已验证
DOI
高影响因子
MATERIALS CHEMISTRY AND PHYSICS
·
2012
·
IF 2.234
Huan Liu,Zi-en Fu,Kai Xu,Hua-lun Cai,Xin Liu,Ming-Cai Chen
A novel Schiff-base liquid crystal diepoxide polymer was prepared via a thermal copolymerization of a Schiff-base epoxy monomer ( PBMBA ) with a diamine co-monomer (MDA). We first proposed that specific effects of highly conjugated Schiff-base moiety on thermal properties of the Schiff-base epoxy polymer ( PBMBA /MDA). Thermal degradation behavior of the polymer was characterized using thermogravimetric analysis (TGA) under nitrogen and under air, respectively. Thermogravimetric data obtained from TGA under nitrogen and under air reveal that PBMBA /MDA exhibits higher thermal stability compared with bisphenol-A type epoxy polymer (DGEBA/MDA) and other mesogene-containing epoxy polymer. It is worth pointing out that the outstanding residual char value for the Schiff-base epoxy polymers had been rarely reported. For thermal degradation mechanism of PBMBA /MDA under nitrogen, thermogravimetric analysis/infrared spectrometry (TG-IR) were used to investigate volatile components, and scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) was used to explore morphologies and chemical components of the residual char. The effects of calcination temperature and calcination time on evolution of morphologies and chemical components of the residual char have been studied. It is proposed that the highly π-conjugated Schiff-base moiety is not only involved in a formation of intramolecular hydrogen bonding increasing the onset thermal degradation temperature ( T d ), but also possesses an effective charring ability retarding a further degradation of polymers. Due to the presence of the specific effects, the thermal stability of the Schiff-base epoxy is improved.
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Haipeng Jiang,Xin Qu,Li He,Zheng Lv,Dan Li,Fengyou Wang,Lin Fan,Jinghai Yang,Lili Yang,Yongsheng Yan
Additive engineering is an effective defect passivation strategy for perovskite solar cells since the functional groups of additives can form coordination with defects. With the diversification of additive molecule structure and their functional groups, the interaction among groups within molecules has become more and more remarkable. However, its corresponding influence mechanism on defects passivation of perovskite is still an open question. Herein, we pay attention to the long-range conjugation effect (LRCE) within additive molecules, since it can greatly influence the electron cloud density in the aromatic system and changes the inherent characteristics of functional groups to weaken their coordination ability. The electrostatic potential (ESP) and bond dissociation energy (BDE) calculation were used to prove that the relative position of –OH and –COOH groups within additives plays a great role in adjusting LRCE. And meta -structure of –OH and –COOH exhibits effective suppression on LRCE to make the groups maintain their inherent characteristics to the great extent. Based on this novel meta -structure additive design strategy, we selected 3-hydroxybenzoic acid (M2), 2-hydroxypyridine-4-carboxylic acid (M3) and 2-hydroxyquinoline-4-carboxylic acid (M4) as additives. These meta -position additives indeed effectively passivate the defects of perovskite films and gradually improve the device performance due to the introduction of heteroatom and more fused ring step by step. The MAPbI 3 -based device with M4 as additive achieved high V oc of 1.17 V and maximum power conversion efficiency (PCE) of 20.40%, and the hygroscopicity was further suppressed so that the unencapsulated PSCs stored for 1000 h in the atmospheric environment still maintain 80% of initial PCE. These results will open a new concept for the design of additive molecules for further development of PSCs.
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
APPLIED SURFACE SCIENCE
·
2018
·
IF 4.439
Xingchen He,Yixu Gu,Shichao Ai,Manman Xie,Qian Lu,Yiqing Wang,Jianquan Wang
A novel graphitic carbon nitride based quantum dots with controllable fluorescence emission wavelength were prepared by changing the primary framework of tri-s-triazine structure. Electron-rich heterocycle embedding of carbon nitride quantum dots with pyrimidine donors effectively increased the conjugation effect of electrons on triazine ring. More importantly, with the increase of asymmetrical heterocycle structures, the fluorescence emission peaks of the quantum dots gradually shifted from 425 nm to 575 nm, and the maximum fluorescence wavelength red shifted 700 nm. The maximum fluorescence quantum yield of this modified quantum dots is up to 22.39%. Those quantum dots have the advantages of improved water solubility and biocompatibility.
研究领域:
材料科学
·
光学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
iScience
·
2022
·
IF 6.107
Zheng Qian,Lingzhen Wang,Mawuli Dzakpasu,Yujia Tian,Dahu Ding,Rongzhi Chen,Gen Wang,Shengjiong Yang
The mechanism of spontaneous Fe III /Fe II redox cycling in iron-centered single-atom catalysts (I-SACs) is often overlooked. Consequently, pathways for continuous SO 4 ·- /HO⋅ generation during peroxymonosulfate (PMS) activation by I-SACs remain unclear. Herein, the evolution of the iron center and ligand in I-SACs was comprehensively investigated. I-SACs could be considered as a coordination complex created by iron and a heteroatom N-doped carbonaceous ligand. The ligand-field theory could well explain the electronic behavior of the complex, whereby electrons delocalized by the conjugation effect of the ligand were confirmed to be responsible for the Fe III /Fe II redox cycle. The possible pyridinic ligand in I-SACs was demonstrably weaker than the pyrrolic ligand in Fe III reduction due to its shielding effect on delocalized π orbitals by local lone-pair electrons. The results of this study significantly advance our understanding of the mechanism of spontaneous Fe III /Fe II redox cycling and radical generation pathways in the I-SACs/PMS process.
研究领域:
催化
·
环境化学
·
材料科学
✓ 已验证
DOI
PubMed
高影响因子
FUEL
·
2018
·
IF 4.908
Yang Zhou,Lu Li,Lijun Jin,Jian Zhou,Zhiwei Shi,Yang Li,Haoquan Hu
Coal pyrolysis is generally considered to initiate by cleavage of weak covalent bonds bridged between aromatic rings. The C–C covalent bonds are predominant bridged linkages among the framework of coal, which have a critical influence on coal pyrolysis reaction but lack of direct online observation. Five representative coal-related model compounds containing C–C bridged bonds, polypropylene (PP), polyvinylpyrrolidone (PVP), poly-4-vinylpyridine (P4VP), polystyrene (PS) and poly-4-vinylphenol, were selected to pyrolyze in an in-situ pyrolysis vacuum ultraviolet photoionization mass spectrometry (Py-VUV-PIMS). The soft ionized mass spectral detection can provide product distribution and evolved information of original products and intermediates, which are the key evidence to understand the initiation, recombination and reaction routes during pyrolysis process. Online analysis of pyrolysis reaction was found to be priority with cracking of C–C bond in the five polymer samples, and homologous free radicals and original products, which mainly include monomers, dimers and their alkyl and alkenyl radicals, were detected. The results reveal the cleavage temperature of C–C covalent bond is deeply related to its chemical environment, and obvious conjugation effect and steric effect for the bridged linkage were observed. In addition, the effect of hydrogen bond was also observed during the pyrolysis of model compounds containing hydroxyl groups, and intramolecular or intermolecular hydrogen bonding reduced the temperature at which C–C bridged bonds break. The analogous fracture mode and pyrolysis behavior of coal-related model compounds, which are beneficial to understand the reaction route and mechanism of coal pyrolysis, were discussed based on the experimental observations and theoretical calculation.
研究领域:
化学工程
·
分析化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）