YaNing He

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Name: 和亚宁; YaNing He
Organization: Tsinghua University
Department: Department of Chemical Engineering
Title: Associate Professor

TOPICS

Co-reporter:Jilei Wang, Bing Wu, Shang Li, Garry Sinawang, Xiaogong Wang, and Yaning He
ACS Sustainable Chemistry & Engineering 2016 Volume 4(Issue 7) pp:4036
Publication Date(Web):June 8, 2016
DOI:10.1021/acssuschemeng.6b00975
Lignin-based azo polymer-bearing pseudo-stilbene-type azo chromophores have been synthesized by a post-azo coupling reaction between the modified alkali lignin and diazonium salts of 4-aminobenzoic acid in DMF with high yield. The polymer synthesized was characterized by using spectroscopic methods. Significant dichroism and surface relief patterns could be photoinscribed on the prepared azo polymer films by using appropriate laser beams. Self-assembly of the lignin-based polymer in selective solvents (THF/H2O) can give uniform colloidal spheres, which can be elongated along the polarization direction of the irradiation light. This novel synthesized lignin-based azo polymer could potentially be used for applications such as reversible optical data storage, photoswitching, sensors, and other photo-driven devices, which provide a simple strategy for value-added utilization of lignin biomass resources.Keywords: Azo polymer; Lignin based; Photoinduced deformation; Self-assembly; Surface relief patterns
Co-reporter:Jilei Wang, Shang Li, Bing Wu, Yaning He
European Polymer Journal 2016 Volume 84() pp:236-244
Publication Date(Web):November 2016
DOI:10.1016/j.eurpolymj.2016.09.030
•Amphiphilic diblock copolymer with an azobenzene linkage has been synthesized.•Treated with azoreductase, the copolymer chain will be broken by the cleavage of the azobenzene linkage.•Time dependent enzyme responsive process of the self-assembly aggregates was studied.Amphiphilic diblock copolymer with an azobenzene linkage has been synthesized by the combination of macromolecular azo coupling reaction and nitroxide-mediated radical polymerization (NMP). In this strategy, an azobenzene linkage would naturally establish at the copolymer junction of the amphiphilic diblock copolymer after the macromolecular azo coupling reaction. Self-assembly of this azobenzene linked copolymer in selected solvents can result uniform self-assembly aggregates. In the presence of enzyme azoreductase and coenzyme NADPH, the amphiphilic diblock copolymer chain will be broken by the cleavage of the azobenzene linkage, which will lead to the disruption of the self-assembly aggregates. UV–vis absorption spectra measurements indicated the release of Nile red, a hydrophobic dye, encapsulated by the self-assembly aggregates. Thus, the amphiphilic diblock copolymer with azobenzene linkage can potentially be applied for the fabrication of nanocarriers for colon-specific delivery purposes applications.
Co-reporter:Jilei Wang, Yiyun Ouyang, Shang Li, Xiaogong Wang and Yaning He  
RSC Advances 2016 vol. 6(Issue 62) pp:57227-57231
Publication Date(Web):08 Jun 2016
DOI:10.1039/C6RA12129B
Amphiphilic diblock copolymers with an azobenzene linkage were synthesized by a macromolecular azo coupling reaction between a PEG based macromolecular diazonium salt and a PS based polymeric block with a functional terminus. Colloidal aggregates could be directly prepared by self-assembly of the prepared amphiphilic copolymer in selective solvents (THF/H2O). By irradiation with UV light, the azobenzene linkage in the block copolymer can be efficiently photocleaved. Thus, the colloidal aggregates of the amphiphilic diblock copolymer will be disrupted due to the cleavage of the azobenzene junction.
Co-reporter:Garry Sinawang, Jilei Wang, Bing Wu, Xiaogong Wang and Yaning He  
RSC Advances 2016 vol. 6(Issue 15) pp:12647-12651
Publication Date(Web):25 Jan 2016
DOI:10.1039/C5RA27014F
A photochromic aggregation-induced emission (AIE) active polymer containing dithienylethene (DTE) and tetraphenylethene (TPE) moieties was synthesized through a nucleophilic substitution reaction between 1,2-bis[5′-(4′′-hydroxyphenyl)-2′-ethylthien-3′-yl]perfluorocyclopentene and 1,2-bis[4-(bromomethyl)phenyl]-1,2-diphenylethene. The prepared polymer is soluble in various organic solvents and can be easily processed into thin film. The DTE chromophores in the polymer can undergo reversible photoisomerization between their open and closed forms upon irradiation with UV and visible light. Thus, the fluorescence of the prepared AIE polymer can be photoswitched.
Co-reporter:Renbo Wei;Jinyi Ma;Hongxing Zhang
Journal of Applied Polymer Science 2016 Volume 133( Issue 29) pp:
Publication Date(Web):
DOI:10.1002/app.43695

ABSTRACT

In this study, we report the synthesis, characterization, and photo-responsive properties of a new Y-shaped amphiphilic azo triblock copolymer composed of two isotropic polyethylene glycol (PEG) blocks and an azobenzene liquid crystalline block. The azo block, with two ending groups suitable for the azo coupling reaction, is polymerized by atom transfer radical polymerization with a synthesized initiator containing two functional terminal groups. The macromolecular diazonium salts are prepared by the diazotization of PEG terminated with an amino group. The triblock copolymer is obtained by the azo coupling reaction between the azo block and macromolecular diazonium salts in DMF under mild condition. The intermediates and the obtained triblock copolymer are characterized by 1H NMR, FT-IR, GPC, POM, DSC, TEM, and UV-vis. The photoinduced isomerization behavior of the azo copolymer is investigated by UV-vis. With the addition of water into the solution of the triblock copolymer, spherical aggregates with an average diameter of about 400 nm can be easily obtained. The aggregates are elongated when irradiated with polarized 365 nm UV light. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43695.

Co-reporter:Jilei Wang;Xiaogong Wang
Journal of Polymer Science Part B: Polymer Physics 2016 Volume 54( Issue 18) pp:1838-1845
Publication Date(Web):
DOI:10.1002/polb.24086

ABSTRACT

A new aggregation-induced emission (AIE) active polymer (PS-TPE) with high tetraphenylethene (TPE) loading density was synthesized. The synthesized polymer showed significant AIE properties, good solubility and high thermal stability. Soft-lithographic contact printing process by using photoinduced surface relief structures on azo polymer film as masters and duplicated PDMS elastomer as stamps was used to fabricate fluorescent PS-TPE patterns. Various fluorescent structures with high contrast including surface relief gratings, periodically dotted patterns, and quasi-crystal structures can be easily fabricated through this approach. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016, 54, 1838–1845

Co-reporter:Jilei Wang, Shihang Wang, Yuqi Zhou, Xiaogong Wang, and Yaning He
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 30) pp:16889
Publication Date(Web):July 13, 2015
DOI:10.1021/acsami.5b05651
A novel 4-arm shaped amphiphilic azobenzene compound was synthesized. The tetraphenylethylene (TPE) core precursor was prepared and further modified by azo coupling reaction at the four peripheral groups. Colloidal spheres could be directly prepared by self-assembly of the prepared amphiphilic azobenzene compound in selective solvents (THF/H2O), which were characterized by using transmission electron microscopy. The colloid diameters could be controlled by adjusting the initial compound concentration and water-adding rate in the preparation processes. By irradiation with visible linearly polarized LED light (450 nm), fast photoinduced deformation of the colloidal spheres along the polarization direction was observed. A very large deformation degree (l/d > 4) could be easily obtained.Keywords: azobenzene; colloidal spheres; deformation; linearly polarized light; self-assembly
Co-reporter:Jilei Wang, Yuqi Zhou, Xiaogong Wang and Yaning He  
RSC Advances 2015 vol. 5(Issue 13) pp:9476-9481
Publication Date(Web):23 Dec 2014
DOI:10.1039/C4RA14926B
The synthesis of AB2 Y-shaped amphiphilic block copolymers by macromolecular azo coupling reaction is reported. The hydrophobic block with the functional group at the end of the polymeric chain was prepared by controlled radical polymerization methods such as RAFT and ATRP. The hydrophilic block with diazonium salt group was obtained by the diazotization of V-shaped aniline-functionalized PEG. Then Y-shaped block copolymers were easily prepared through macromolecular azo coupling reactions between the abovementioned two polymeric blocks. The results of experiments showed that the position of the functional group suitable for azo coupling reaction in the polymeric chain has considerable effect on the efficiency of macromolecular azo coupling reaction. It was easier for the macromolecular diazonium salts to attack the functional groups when they were at the end of the macromolecular chains instead of in the middle. The self-assembly properties of the obtained Y-shaped amphiphilic block copolymers were also studied. Colloidal spheres were prepared by gradual hydrophobic aggregation of the polymeric chains in a THF–H2O dispersion medium.
Co-reporter:Yaning He, Yan Zhu, Zhen Chen, Wei He and Xiaogong Wang  
Chemical Communications 2013 vol. 49(Issue 49) pp:5556-5558
Publication Date(Web):30 Apr 2013
DOI:10.1039/C3CC41538D
In this communication, a novel photochromic molecular switch DTE-2(Azo-CN) containing both dithienylethene and push–pull azo chromophores was synthesized. The push–pull azo chromophores can significantly accelerate the ring opening of the C–C bond of DTE closed isomer when irradiated with light far away from the maximum absorption band of the DTE closed isomer.
Co-reporter:Yaning He, Wei He, Dan Liu, Tonghan Gu, Renbo Wei and Xiaogong Wang  
Polymer Chemistry 2013 vol. 4(Issue 2) pp:402-406
Publication Date(Web):29 Aug 2012
DOI:10.1039/C2PY20653F
We report a novel modular strategy for the synthesis of block copolymers via the combination of a macromolecular azo coupling reaction and a reversible addition fragmentation chain transfer (RAFT) polymerization method. One block, with a terminus suitable for an azo coupling reaction, was obtained by RAFT polymerization using a synthesized chain transfer agent (CTA) with the designed functional group. The other block, with a diazonium salt terminus, was obtained by the diazotization of aniline-functionalized PEG, which was prepared by a nucleophilic substitution reaction between the synthesized tosylate ended mPEG and p-aminobenzoic acid. The macromolecular azo coupling reaction between the above two polymer blocks was carried out in a polar organic solvent such as DMF under extremely mild conditions. Block copolymers with well-defined structures can be efficiently prepared through this approach.
Co-reporter:Yaning He, Wei He, Renbo Wei, Zhen Chen and Xiaogong Wang  
Chemical Communications 2012 vol. 48(Issue 7) pp:1036-1038
Publication Date(Web):15 Nov 2011
DOI:10.1039/C1CC16362K
This communication reports a new approach to synthesize amphiphilic block copolymers. The copolymers with well-defined structures were synthesized by macromolecular azo-coupling reaction between the diazonium salt of aniline-functionalized PEG and the polymeric blocks with a terminal suitable for the azo-coupling reaction.
Co-reporter:Zhen Chen;Yang Wang ;Xiaogong Wang
Macromolecular Rapid Communications 2011 Volume 32( Issue 13) pp:977-982
Publication Date(Web):
DOI:10.1002/marc.201100142
Co-reporter:Yaning He, Wei He, Renbo Wei, Zhen Chen and Xiaogong Wang
Chemical Communications 2012 - vol. 48(Issue 7) pp:NaN1038-1038
Publication Date(Web):2011/11/15
DOI:10.1039/C1CC16362K
This communication reports a new approach to synthesize amphiphilic block copolymers. The copolymers with well-defined structures were synthesized by macromolecular azo-coupling reaction between the diazonium salt of aniline-functionalized PEG and the polymeric blocks with a terminal suitable for the azo-coupling reaction.
Co-reporter:Yaning He, Yan Zhu, Zhen Chen, Wei He and Xiaogong Wang
Chemical Communications 2013 - vol. 49(Issue 49) pp:NaN5558-5558
Publication Date(Web):2013/04/30
DOI:10.1039/C3CC41538D
In this communication, a novel photochromic molecular switch DTE-2(Azo-CN) containing both dithienylethene and push–pull azo chromophores was synthesized. The push–pull azo chromophores can significantly accelerate the ring opening of the C–C bond of DTE closed isomer when irradiated with light far away from the maximum absorption band of the DTE closed isomer.
Benzene, 1,1'-(1,2-diphenyl-1,2-ethenediyl)bis[4-methyl-
BENZONITRILE, 4-[[4-[(6-HYDROXYHEXYL)OXY]PHENYL]AZO]-
1-METHOXY-4-(1,2,2-TRIPHENYLETHENYL)BENZENE
Benzenamine,N-ethoxy-N-ethyl-
4-CARBOXY-2,2,6,6-TETRAMETHYLPIPERIDINE 1-OXYL
Benzonitrile, 4-[2-(4-hydroxyphenyl)diazenyl]-
Benzenediazonium, 4-cyano-