LANGMUIR
·
2010
·
IF 3.898
Jinqiang Jiang,Qiaozhen Shu,Xin Chen,Yiqun Yang,Chenglin Yi,Xiaoqing Song,Xiaoya Liu,Mingqing Chen
A novel photosensitive C-PNIPAAm comprising hydrophilic PNIPAAm conjugated with a relatively short but very hydrophobic coumarin part was designed and prepared using a coumarin-containing disulfide derivative (C-S-S-C) as transfer agent in the presence of Bu3P and water. It was found that C-PNIPAAm can form polymer micelles in aqueous solution. And the micellar morphology in aqueous solution can be photoswitched into hollow spheres according to the photodimerization of coumarin end groups upon 365 nm irradiation and reform the micellar morphology after the subsequent photoscission of dimers upon 254 nm. This instant morphology changing phenomenon was successfully monitored by dynamic light scattering (DLS) and transmission electron microscopy (TEM) measurements. TEM observations showed the small spherical shape of micelles with diameter at 30−50 nm before photo-cross-linking, the big vesicles with diameter at 200−350 nm after photo-cross-linking, and the small micelles with diameter at 30−50 nm after the subsequent photo-de-cross-linking in the first irradiation cycle. The reason for this significant morphology switching can be attributed to the reversible photoinduced amphiphilic structure transformation between the telechelic “hydrophobic end−hydrophilic chain” structure and the ABA type of “hydrophilic chain−hydrophobic center−hydrophilic chain” one upon alternating irradiation.
研究领域:
高分子化学
·
材料科学
·
纳米技术
✓ 已验证
DOI
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 53
·47498-47508
·
IF 3.289
Yan Yuan,Yulin Zhang,Ren Liu,Jingcheng Liu,Zhiquan Li,Xiaoya Liu
In this study, 7-(4-vinylbenzyloxyl)-4-methylcoumarin (VM) and maleic anhydride (MA) were polymerized through free radical copolymerization to form a photosensitive alternating copolymer P(VM-alt-MA) (PVMA). PVMA was used as a soft template to achieve the oxidative polymerization of poly(3,4-ethylenedioxythiophene) (PEDOT). We obtained a stable PEDOT:PVMA photosensitive aqueous dispersion with an average diameter in the range of 140 to 210 nm. We then used this aqueous dispersion as the ink for fabricating humidity sensors through inkjet-printing on a paper substrate. The printed photosensitive conductive film PEDOT:PVMA could be cross-linked after photo-dimerisation of coumarin groups, leading to a small decrease of electrical conductivity, but also appreciable improvements in water resistance and sensor robustness. The humidity sensing ability of these PEDOT:PVMA/paper sensors was investigated by exposing them to a wide range of relative humidity, namely 11–97% at room temperature. These paper sensors could selectively and reversibly detect water vapor with a significant linear relationship. The response strength and the response/recovery time of the sensors show a substantial improvement compared with those of previous reports. The photo-dimerisation of PEDOT:PVMA improves the stability of humidity response and the response/recovery time of the sensors.
研究领域:
材料科学
·
传感器技术
·
化学工程
✓ 已验证
DOI
高影响因子
POLYMER
·
2024
·
IF 4.1
Bin Pu,Gaolang Xiao,Juying Xiao,Hua-Bing Yin,Jin Wang
Self-healing materials based on photodimerization have advantages such as being fast, efficient, environmentally friendly and controllable. However, most of photoresponsive self-healing materials suffer from a problem that there is a compromise between the strength and the self-healing efficiency. Therefore, most of the research focuses on using flexible materials to reach high self-healing efficiency. The absorption wavelengths of some photosensitive groups are narrow, which limits the application fields of self-healing properties of self-repairing materials. Here, we use photodimerizable thymine as the photoresponsive group and exploit the sensitivity of a methoxyacetophenone photosensitizer to increase the self-healing efficiency of a rigid membrane material from beyond repairing to 85% recovery under the same conditions. The tensile strength of the self-healing material is 33.88 MPa, and the elastic modulus reaches 3 GPa after 80 min of photo-irradiation at 308 nm. The maximum thermogravimetric decomposition rate temperature exceeds 400 °C, exhibiting their excellent thermal stability. This strategy provides a novel and effective approach to endow rigid materials with high self-healing efficiency at benign conditions, and opens a new avenue to functionalise a wide range of rigid engineering materials.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
COLLOID AND POLYMER SCIENCE
·
2014
·Vol. 293
·期 3
·823-831
·
IF 2.41
Chang Huan,Liu Yan,Shi Mei,Liu Zhaotie,Liu Zhongwen,Jiang Jinqiang
The water-soluble amphiphilic random copolymer of P(DMA- co -VBC) with coumarin pendants has been designed to investigate the photo-induced dynamic association of coumarin pendants within polymer micelles in aqueous solution. Methods of absorption and emission spectra, solution transmittance, dynamic light scattering (DLS), and atomic force microscope (AFM) were applied. It was found that P(DMA- co -VBC) can form polymer micelles in aqueous solution. The time-dependent photo-dimerization degree (PD) of polymer micelles upon different intensity irradiations of 320 nm light showed saturating behaviors with an intensity-independent value of the maximum photo-dimerization extent, while the maximum photo-cleavage extent of coumarin dimers declined with the increasing intensity of 254 nm irradiation at used conditions. Furthermore, a significant emission band at 445 nm ( I
2
) evidently emerged as against the disappearance of emission band at 385 nm ( I
1 ) during the photo-dimerization, and the time-dependent I
2
/I
1 ratios of polymer aqueous solution upon alternative irradiations of 320 and 254 nm light showed a wave-like increase as a function of irradiation cycles, indicating a wavy closeness of coumarin pendants within polymer micelles during the reversible photo-dimerization cycles.
研究领域:
高分子化学
·
光化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY
·
2018
·
IF 2.891
Xueqin Wei,Xingke Yu,Yuxue Zhang,Wenting Liang,Jiecheng Ji,Jiabin Yao,Ming Rao,Wanhua Wu,Cheng Yang
A series of primary-face- or secondary-face-modified β-cyclodextrins (CDs) 7 - 11 were prepared for mediating the enantiodifferentiating [4 + 4] photocyclodimerization reactions of 2-anthracenecarboxylic acid (AC). The complexation behavior of these hosts with AC was studied by 1 H NMR, UV–vis, circular dichroism spectroscopy and ITC titration. The product distribution and product’s ee turned out to be a critical function of the skeleton and periphery modifications of β-CD. The combined yields of slipped cyclodimers 5 and 6 were greatly enhanced in the presence of modified β-CDs. In contrast to native β-CD and other β-CD derivatives, host 9, in which a phenyltriazolyl group was introduced on the primary face of β-CD, afforded antipodal cyclodimer 6 in a much higher enantioselectivity of 46% ee. The influence of temperature and salt additives were investigated in depth. Intriguingly, product chirality was switched by temperature in the presence of 6 M CsCl. Under an optimized condition, host 8 gave slipped cyclodimer 6 in 70% ee, which is the highest enantioselectivity ever reported for the slipped cyclodimer.
研究领域:
有机化学
·
超分子化学
✓ 已验证
DOI
高影响因子
EUROPEAN POLYMER JOURNAL
·
2019
·
IF 3.621
Yiyang Gu,Chunyu Ru,Zhen Zhao,Danming Chao,Xincai Liu
Shape memory polymers have attracted much attention due to their promising applications in biomedicine, textiles, aerospace et al. Here, novel poly(aryl ether ketone)s bearing flexible alkyl segments and pendant anthracene groups were synthesized via nucleophilic copolycondensation coupled with post-polymerization functionalization. Their chemical structure, thermostability and mechanical properties were characterized through Fourier Transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, thermal gravimetric analysis and dynamic mechanical analysis. The soft-rigid alternative segment structure endows these poly(aryl ether ketone)s with promising shape memory properties. After the photodimerization of pendant anthracene units, the resultant polymers exhibit enhanced shape memory performance in terms of satisfying shape fixity ratio and high shape recovery ratio, attributed to their photocrosslinked polymeric network architecture. This shape memory polymer with reversible photodimerization holds great promise for a deep understanding of the mechanism and future applications.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry C
·
2023
·Vol. 11
·期 41
·14217-14225
·
IF 6.4
Potao Sun,Zeyan Shi,Wenxia Sima,Xinyu Tang,Tao Yuan,Ming Yang,Hang Xu,Zhaoping Li
Microscale damage, including cracks and electrical trees, is inevitably generated in the polymer insulation materials used in the packaging of power equipment and power electronic devices during long-term operation, which leads to premature insulation failure or even widespread power outages. Self-healing insulation materials are the most promising way to solve this problem. However, the mechanical/electrical strength or the dimensional stability of the materials could be sacrificed during the repair process, which has limited their application as insulation materials. In this study, we report an intrinsic self-healing epoxy resin based on reversible anthracene photodimerization (ISEP-RAP) that remains mechanically robust while ensuring efficient healing via a reversible reaction. The damaged area is decrosslinked by 254 nm UV and thermal excitation, which accelerates the molecular chain diffusion to the damaged area to fill and repair the damaged channels. The ISEP-RAP is recrosslinked by 365 nm UV to restore the mechanical and electrical properties after self-healing. Due to the combined action of the epoxy-amine permanent crosslinking sites and the anthracene reversible crosslinking sites, high crosslinked ISEP-RAP possesses excellent tensile and dielectric strength similar to that of standard epoxy resin and a lower permittivity constant. Importantly, the decrosslinked ISEP-RAP still possesses sufficiently high strength to keep the macrostructure unchanged. ISEP-RAP achieves high-efficiency, repeatable, non-contact intrinsic self-healing of scratches and electrical trees with whole-process dimensional stability. This work provides a new method for intrinsic self-healing in mechanically robust insulation materials to eliminate microdamage with repeatability, high reliability, and high efficiency.
研究领域:
材料科学
·
电气工程
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2018
·
IF 3.141
Wenhua Xu,Yuanhai Su,Yang Song,Minjing Shang,Li Zha,Qinghua Lu
Cyclobutanetetracarboxylic dianhydride (CBDA) was prepared by photodimerization of maleic anhydride in capillary microreactors within Taylor flow under UV irradiation. Both inert gas and ultrasound were introduced into this photochemical process to avoid the potential channel clogging resulting from the CBDA deposition. Higher input power of the Hg lamp, lower reactant concentration, longer residence time, and smaller inner diameter of the capillary were found to result in higher CBDA yield. The yield of CBDA could reach as high as 66.3% at an actual residence time of 30 min in the capillary microreactor with 0.5 mm inner diameter. According to the analysis of energy conversion, only low effective photoelectric transformation efficiencies could be achieved in this photochemical process. However, the photonic efficiency for this photodimerization carried out in capillary photomicroreactors was much higher compared to batch photoreactors and was comparable with that for other photochemical transformations using similar photomicroreactors and light sources.
研究领域:
化学工程
·
光化学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2021
·
IF 9.229
Qiwen Yan,Lina Mao,Bang Feng,Lidong Zhang,Yiqian Wu,Wei Huang
A series of novel humidity-responsive and photosensitive polymer films (PCA–PAA–PEG) are prepared. These films can be patterning cross-linked by the photodimerization of coumarin pendant groups. The humidity-induced deformation can be well controlled by the pattern because of the different modulus and hydrophilicity between cross-linked and un-cross-linked segments. In addition, the pattern can be erased and the deformation direction can be changed programmatically by the de-cross-linking–re-cross-linking approach due to the reversible photodimerization of coumarin groups. The cross-linking degree also affects the humidity responsiveness of the film. The deformation of the gradient patterning cross-linked film can be more accurately controlled. Moreover, the length and width ratio (L/Ws/Wh) of the un-cross-linked segment to the cross-linked segment affects the deformation of the films as well. When L/Ws/Wh is 5/2/1 or 5/3/1, the deformation is controllable, and when L/Ws/Wh is 5/1/1 or 5/4/1, the deformation is random at the initial stage, but the whole film will bend along the short axis in the end.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Flow Chemistry
·
2022
·Vol. 12
·期 1
·91-100
·
IF 3.264
Xu Wenhua,Pan Yizhe,Chen Liuyang,Su Yuanhai,Shang Minjing,Lu Xuemin,Lu Qinghua
The combination of continuous-flow microreactors and photoreaction is one of the important researches in flow chemistry. Dimethyl-substituted cyclobutanetetracarboxylic dianhydride (DM-CBDA) was prepared through photodimerization in photomicroreactors and applied in the preparation of polyimide films. It was found that ethyl acetate as the solvent and an appropriate concentration of substrate could benefit this photodimerization process in the capillary photomicroreactor. Higher photonic efficiency and higher DM-CBDA yield were obtained in the photomicroreactor as compared to batch photoreactors. DM-CBDA was applied to prepare the colorless transparent polyimide films, which showed a high polymerization activity for the preparation of poly(amic acid) with high molecular weight. A PI film of DM-CBDA/ODA with the UV cutoff wavelength of 295 nm, the glass transition temperature of 376 °C, and the elongation at break of 11.3% was prepared. This work broadens the application of photomicroreactors for the preparation of polyimide monomers in flow chemistry and its films with good transparent, thermal and mechanical properties.
研究领域:
材料化学
·
高分子科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL RESEARCH IN CHINESE UNIVERSITIES
·
2020
·Vol. 36
·期 5
·816-820
·
IF 1.063
Chu Ning,Xu Shuping,Xu Weiqing
Two different kinds of configurations of 1,4-bis[2-(4-pyridyl)ethenyl]-benzene( trans -bpeb and cis -bpeb) were achieved, and a bpeb dimer was synthesized in dimethyl sulfoxide(DMSO). Compared with the previous work that synthesized the bpeb dimer or polymer in crystal with a template agent needed, the reaction occurred in a solution phase in the present method. A hand-held ultraviolet lamp(365 nm) with the power of 12 W and the Watt density of 0.35 mW/cm 2 can realize the photodimerization of bpeb, instead of the high-power mercury lamp in most previous studies. Unlike other 2+2 cycloaddition in liquid state using catalysts even noble metals, no catalysts were required here, which is cost-saving. Only the trans -pbeb can start the cycloaddition and the formation of the close J-aggregations of trans -pbeb in DMSO is a precondition for explaining the 2+2 photodimerization. The productivity for the 2+2 cycloaddition product was achieved as 55.6%.
研究领域:
有机化学
·
光化学
·
超分子化学
·
材料化学
·
合成方法学
✓ 已验证
DOI
高影响因子
MACROMOLECULES
·
2024
·
IF 5.1
Zichao Deng,Aihua Chen
Stimulus-responsive nanowires are attractive and expected to be used in diversified fields, but their application is usually affected by an inefficient synthetic process, impure morphologies, and unsteadiness in organic solvents. Meanwhile, the reversibility of the response is also challenging. Here, we present a new method incorporating polymerization-induced hierarchical self-assembly (PIHSA) and photodimerization to prepare cross-linked triblock copolymer nanowires, which were synthesized by the successive polymerization of methacrylate monomers containing azobenzene (MAAz) and stilbene (MAStb). The formation of nanowires was related to the highly ordered stacking of stilbene, and their heterostructures could be clearly identified by the distinct regions comprising azobenzene and stilbene at the periphery and center of the cores, respectively. Upon UV irradiation, the dimerization of stilbene cross-linked the structure and made the nanowires tolerant to good solvents. The cross-linked nanowires with appropriate block ratios were photoresponsive, which could reversibly expand and slim upon alternative UV/visible light irradiation due to the well-defined distribution of azobenzene and stilbene. This work will open a new door for the development and application of stimulus-responsive nanowires owing to their fascinating reversible deformation and distinguished stability.
研究领域:
材料科学
·
纳米技术
·
高分子化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）