15 results on '"Zhang, Zhengbiao"'
Search Results
2. Unraveling Dynamic Helicity Inversion and Chirality Transfer through the Synthesis of Discrete Azobenzene Oligomers by an Iterative Exponential Growth Strategy.
- Author
-
Wang, Xiao, Yu, Zhihong, Huang, Zhihao, Zhou, Nianchen, Cheng, Xiaoxiao, Zhang, Zhengbiao, Zhang, Wei, and Zhu, Xiulin
- Subjects
- *
POLYDISPERSE polymers , *THERMODYNAMICS , *CHIRALITY , *AZOBENZENE , *OLIGOMERS , *SMART materials - Abstract
Unraveling the chirality transfer mechanism of polymer assemblies and controlling their handedness is beneficial for exploring the origin of hierarchical chirality and developing smart materials with desired chiroptical activities. However, polydisperse polymers often lead to an ambiguous or statistical evaluation of the structure–property relationship, and it remains unclear how the iterative number of repeating units function in the helicity inversion of polymer assemblies. Herein, we report the macroscopic helicity and dynamic manipulation of the chiroptical activity of supramolecular assemblies from discrete azobenzene‐containing oligomers (azooligomers), together with the helicity inversion and morphological transition achieved solely by changing the iterative chain lengths. The corresponding assemblies also differ from their polydisperse counterparts in terms of thermodynamic properties, chiroptical activities, and morphological control. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
3. Novel Near‐Infrared Fluorescent Nanoprobe Synthesized by the RAFT‐Mediated PISA Strategy for Hypoxia‐Triggered Tumor Imaging and Azoreductase‐Responsive Drug Release.
- Author
-
Wang, Shuyuan, Wang, Yuqing, Lei, Huali, Li, Lishan, Cheng, Liang, Zhou, Nianchen, Zhang, Wei, Zhang, Zhengbiao, and Zhu, Xiulin
- Subjects
- *
TARGETED drug delivery , *DRUG delivery systems , *DRUG carriers , *CELL imaging , *DRUG therapy , *COLON cancer , *DIBLOCK copolymers - Abstract
Drug carriers and visual tracking play an important role in accurate and efficient drug delivery systems for targeted drug therapy. Polymerization‐induced self‐assembly (PISA), a powerful strategy for the fabrication of stimuli‐responsive polymeric nanoparticles has been a focus over the past decade due to its promising applications in biomedical fields such as targeted drug delivery and fluorescent nanoprobes used for tumor imaging. Herein, hypoxia‐responsive near‐infrared (NIR) fluorescent nanoprobes of amphiphilic block copolymers (PPEGMA14‐ADP‐Azo‐PBzMAx) are reported, the first example synthesized by RAFT‐mediated PISA strategy in situ to realize synchronous drug release and cell imaging. First, a series of nanoparticles with different morphologies and sizes, including spheres and vesicles, are synthesized by the PISA strategy using PPEGMA14‐ADP‐Azo‐CDPA as macro‐RAFT agents link with near‐infrared Aza‐BODIPY fluorogen and azobenzene groups. Hypoxia‐triggered dissociation of the nanoprobes and NIR fluorescence emission is then observed because of the cleavage of azo bonds. Meanwhile, the in situ DOX‐loaded nanoprobes by the PISA demonstrate synchronous drug release and NIR fluorescence enhancement against mouse colon cancer cells (CT26) under hypoxia (1% O2) compared with under normoxia (16% O2). [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
4. A Consequence of Dispersity on the Self‐Assembly of Amphiphilic Homopolymers Containing Main‐Chain Azobenzene.
- Author
-
Hu, An, Shi, Xianheng, Li, Lishan, Zhang, Wei, Zhang, Zhengbiao, Zhou, Nianchen, and Zhu, Xiulin
- Subjects
- *
AZOBENZENE , *OLIGOMERS , *MICELLES , *PHOTOISOMERIZATION , *NANOSTRUCTURED materials - Abstract
The self‐assembly of amphiphilic oligomers/polymers is a versatile and promising approach for creating nonspherical polymeric nanoparticles. Discrete amphiphilic oligomers/polymers with molecularly defined structures are ideal candidates for fabricating smart nanoparticles and for achieving a deeper understanding of structure‐controlled self‐assembly. Herein, discrete and disperse amphiphilic homopolymers of PAZOnTEG2n, with hydrophobic azobenzene are designed and synthesized as the main chains tethered with hydrophilic tetraethylene glycol monomethyl ether (TEG) units, to accurately investigate the impact of dispersity on their self‐assembly in solution. The discrete‐PAZO8TEG16 in DMF/water and in THF/water results in the formation of 2D lamellae, while the dispersed counterpart prefers to self‐assemble into spherical micelles. The significant difference is due to their distinction between interior structures of assembly. Furthermore, photoisomerization of azobenzene triggers dissociation/reassembly for discrete polymeric nanoparticles but no obvious change for the dispersed counterparts under irradiation with UV/vis light. This work reveals the influence of dispersity on the self‐assembly of amphiphilic polymers and stimuli‐responsive properties of their nanomaterials, which is desirable for universal applicability in fabricating smart 2D lamellas. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
5. Reversible Photo- and Thermo-Responsive Block Copolymer Micelles Functionalized by NIPAM and Azobenzene.
- Author
-
Huang, Guixian, Zhu, Jian, Zhang, Zhengbiao, Zhang, Wei, Zhou, Nianchen, and Zhu, Xiulin
- Subjects
- *
BLOCK copolymers , *FRAGMENTATION reactions , *ADDITION polymerization , *MICELLES , *AZOBENZENE , *PRECIPITATION (Chemistry) , *PHOTOPOLYMERS , *THERMAL properties of polymers - Abstract
In this report, the photo and thermo dual responsive block copolymer, PVHMA-b-PNIPAM, is synthesized by reversible addition-fragmentation chain transfer polymerization. The structure of copolymer was characterized by GPC and NMR. The copolymer trends to form micelles in water. A photo controlled reversible size changing as well as temperature induced reversible precipitation and dispersion in water was found. [ABSTRACT FROM PUBLISHER]
- Published
- 2013
- Full Text
- View/download PDF
6. Synthesis of Amphiphilic Azobenzene Functionalized Branched-Type Copolymer Based on Branched Poly(2-(Dimethylamino) ethyl methacrylate) and Investigation of Its Drug Release Properties.
- Author
-
Shen, Wei, Xing, Minying, Zhang, Zhengbiao, Zhang, Wei, Cheng, Zhenping, and Zhu, Jian
- Subjects
- *
ORGANIC synthesis , *AMPHIPHILES , *AZOBENZENE , *COPOLYMERS , *POLYMETHACRYLATES , *DRUG delivery systems , *ADDITION polymerization , *OXIDATION-reduction reaction - Abstract
Here, we reported the synthesis of branched poly(2-(dimethylamino) ethyl methacrylate) (PDMAEMA) via a combination of activator generated by electron transfer atom transfer radical polymerization (AGET ATRP) and self-condensing vinyl polymerization (SCVP) techniques. The typical linear kinetics of the AGET ATRP of DMAEMA with the initiation of 2-(2-bromoisobutyryloxy) ethyl methacrylate (BIEM) was observed. The molecular weight (Mn ) of the branched PDMAEMA increased with the monomer conversion. The GPC traces of these polymers were unimodal and the molecular weight distributions (Mw/Mn ) were in the range of 1.30–2.10. The degree of branching (DB) determined by NMR spectra agreed with theoretical value. The branched amphiphilic copolymer functionalized with azobenzene was then prepared via AGET ATRP chain-extension of branched PDMAEMA with azobenzene monomer, 6-[4-(4-methoxyphenylazo)phenoxy]hexyl(meth)acrylate as the second monomer. The GPC traces of these branched copolymers showed the mono-peaks, which proved the successful preparation of copolymers. The properties of this branched copolymer in controlling drug release were also investigated. It was found that the drug release rate of chlorambucil can be controlled by various factors, such as polymer structure, light, temperature and pH values. [ABSTRACT FROM PUBLISHER]
- Published
- 2012
- Full Text
- View/download PDF
7. Synthesis of Discrete Conjugated Fluorene‐Azo Oligomers for the Investigation of Azobenzene Position‐Dependent Physical Properties and Photoresponsive Behavior.
- Author
-
Liu, Min, Shi, Xianheng, Li, Lishan, Zhang, Jiandong, Huang, Zhihao, Zhang, Wei, Zhou, Nianchen, Zhang, Zhengbiao, and Zhu, Xiulin
- Subjects
- *
CONJUGATED oligomers , *OLIGOMERS , *CONJUGATED polymers , *AZOBENZENE , *DENSITY functional theory , *POLYMER structure - Abstract
It is well known that macromolecular structure, including composition, topology and sequence, significantly determines the properties of conjugated polymers/oligomers. To accurately understand the structure‐induced properties, discrete oligomers/polymers with molecularly defined structures are the ideal model because they provide distinct nonstatistical results. Herein, a series of discrete conjugated fluorene‐azo oligomers with different positions of the azobenzene units along the main chain (i.e., sequence) are efficiently prepared based on CuAAC "click" chemistry via a stepwise chain‐growth strategy. Position‐dependent behavior has an evident impact on the properties of oligomers, such as thermal properties, optical properties and photoresponsive behavior in both solution and thin film states. In addition, the fluorene‐azo oligomers show less photodegradation of 9,9‐dioctyl‐fluorene in the solid‐state than oligofluorene during UV light irradiation; however, position‐dependent photodegradation is found in solution. Optimized configurations and UV–vis absorption spectra of fluorene‐azo oligomers are calculated by density functional theory. Experimental results and theoretical analysis indicate that the location of azobenzene can play a dominant role in determining the properties of fluorene‐azo oligomers resulting from sequence‐mandated conformational changes. Undoubtedly, this work can provide deeper insight into the structure–property relationships based on precisely sequence‐defined polymer structures. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
8. Smart supramolecular nanofibers and nanoribbons from uniform amphiphilic azobenzene oligomers.
- Author
-
Li, Lishan, Zhang, Jiandong, Liu, Min, Shi, Xianheng, Zhang, Wei, Li, Yiwen, Zhou, Nianchen, Zhang, Zhengbiao, and Zhu, Xiulin
- Subjects
- *
NANORIBBONS , *NANOFIBERS , *AZOBENZENE , *NANOBELTS , *MOLECULAR weights , *OLIGOMERS - Abstract
A series of self-assembled 1D nanostructures, including straight and helix nanofibers, nanoribbons, and nanobelts, were fabricated from uniform amphiphilic azobenzene oligomers with tunable molecular weight and side chain functionality, promoted by multiple and cooperative supramolecular interactions. Additionally, the morphological transformation of the nanofibers was achieved during the photoisomerization process. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
9. In Situ Controlled Construction of a Hierarchical Supramolecular Chiral Liquid‐Crystalline Polymer Assembly.
- Author
-
Cheng, Xiaoxiao, Miao, Tengfei, Yin, Lu, Ji, Yujin, Li, Youyong, Zhang, Zhengbiao, Zhang, Wei, and Zhu, Xiulin
- Subjects
- *
STACKING interactions , *POLYMERS , *SUPRAMOLECULES , *BLOCK copolymers , *CHIRALITY , *CONSTRUCTION - Abstract
Hierarchical supramolecular chiral liquid‐crystalline (LC) polymer assemblies are challenging to construct in situ in a controlled manner. Now, polymerization‐induced chiral self‐assembly (PICSA) is reported. Hierarchical supramolecular chiral azobenzene‐containing block copolymer (Azo‐BCP) assemblies were constructed with π–π stacking interactions occurring in the layered structure of Azo smectic phases. The evolution of chirality from terminal alkyl chain to Azo mesogen building blocks and further induction of supramolecular chirality in LC BCP assemblies during PICSA is achieved. Morphologies such as spheres, worms, helical fibers, lamellae, and vesicles were observed. The morphological transition had a crucial effect on the chiral expression of Azo‐BCP assemblies. The supramolecular chirality of Azo‐BCP assemblies destroyed by 365 nm UV irradiation can be recovered by heating–cooling treatment; this dynamic reversible achiral–chiral switching can be repeated at least five times. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
10. In Situ Controlled Construction of a Hierarchical Supramolecular Chiral Liquid‐Crystalline Polymer Assembly.
- Author
-
Cheng, Xiaoxiao, Miao, Tengfei, Yin, Lu, Ji, Yujin, Li, Youyong, Zhang, Zhengbiao, Zhang, Wei, and Zhu, Xiulin
- Subjects
- *
STACKING interactions , *POLYMERS , *SUPRAMOLECULES , *BLOCK copolymers , *CHIRALITY , *CONSTRUCTION - Abstract
Hierarchical supramolecular chiral liquid‐crystalline (LC) polymer assemblies are challenging to construct in situ in a controlled manner. Now, polymerization‐induced chiral self‐assembly (PICSA) is reported. Hierarchical supramolecular chiral azobenzene‐containing block copolymer (Azo‐BCP) assemblies were constructed with π–π stacking interactions occurring in the layered structure of Azo smectic phases. The evolution of chirality from terminal alkyl chain to Azo mesogen building blocks and further induction of supramolecular chirality in LC BCP assemblies during PICSA is achieved. Morphologies such as spheres, worms, helical fibers, lamellae, and vesicles were observed. The morphological transition had a crucial effect on the chiral expression of Azo‐BCP assemblies. The supramolecular chirality of Azo‐BCP assemblies destroyed by 365 nm UV irradiation can be recovered by heating–cooling treatment; this dynamic reversible achiral–chiral switching can be repeated at least five times. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
11. The synthesis and photoactive properties of cyclic amphiphilic polymers with azobenzene in main chain.
- Author
-
Jiang, Ganquan, Li, Lishan, Xu, Xiaofei, Lu, Jinjie, Zhu, Xing, Zhang, Zhengbiao, Zhou, Nianchen, and Zhu, Xiulin
- Subjects
- *
POLYMERIZATION research , *AMPHIPHILE synthesis , *AZOBENZENE , *ATOM transfer reactions , *RING formation (Chemistry) , *GEL permeation chromatography , *FOURIER transform infrared spectroscopy , *MATRIX-assisted laser desorption-ionization - Abstract
ABSTRACT The cyclic amphiphilic polymers with azobenzene in main chain, cyclic azobenzene tetraethylene glycol polystyrene ( cyclic-Azo-TEG-PS) with different molecular weights, were successfully synthesized by combining atom transfer radical polymerization (ATRP) and Cu (I)-catalyzed azide/alkyne cycloaddition (CuAAC). Gel permeation chromatography (GPC), proton nuclear resonance (1H NMR), Fourier transform-infrared (FT-IR), and matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectrometry were used to prove the complete conversion from linear polymers to cyclic ones. The thermal properties and photoisomerization behaviors of obtained cyclic polymers have been investigated by comparison with the linear analogues. The cyclic polymer displayed a higher glass transition temperature compared with the linear one, measured by differential scanning calorimetry (DSC). It was found that the trans-to- cis and cis-to- trans isomerization of cyclic polymers was both slower than that of their respective linear counterparts upon irradiation by UV/visible light. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 1834-1841 [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
12. Photoresponsive Amphiphilic Macrocycles Containing Main-Chain Azobenzene Polymers.
- Author
-
Sun, Yadong, Wang, Zhao, Li, Yiwen, Zhang, Zhengbiao, Zhang, Wei, Pan, Xiangqiang, Zhou, Nianchen, and Zhu, Xiulin
- Subjects
- *
PHOTOSENSITIVITY , *HOMOPOLYMERIZATIONS , *BIPHENYL compounds , *AZOBENZENE , *CHROMOPHORES - Abstract
Herein, the first example of photosensitive cyclic amphiphilic homopolymers consisting of multiple biphenyl azobenzene chromophores in the cyclic main chain tethered with hydrophilic tetraethylene glycol monomethyl ether units is presented. The synthetic approach involves sequentially performed thermal catalyzed 'click' step-growth polymerization in bulk, and Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) intramolecular cyclization from α-alkyne/ω-azide linear precursors. It is observed that such amphiphilic macrocycles exhibit increased glass transition temperatures ( Tg), slightly faster trans-cis-trans photoisomerization, and enhanced fluorescence emission intensity compared with the corresponding linear polymers. In addition, the cyclic amphiphilic homopolymers self-assemble into spherical nanoparticles with smaller sizes which possess slower photoresponsive behaviors in a tetrahydrofuran/water mixture compared with those of the linear ones. All these interesting observations suggest that the cyclic topology has a great influence on the physical properties and self-assembly behavior of these photoresponsive amphiphilic macrocycles in general. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
13. Cyclic Amphiphilic Random Copolymers Bearing Azobenzene Side Chains: Facile Synthesis and Topological Effects on Self-Assembly and Photoisomerization.
- Author
-
Cai, Ye, Lu, Jinjie, Zhou, Feng, Zhou, Xiaoji, Zhou, Nianchen, Zhang, Zhengbiao, and Zhu, Xiulin
- Subjects
- *
RANDOM copolymers , *AZOBENZENE , *SUBSTITUENTS (Chemistry) , *MOLECULAR self-assembly , *PHOTOISOMERIZATION , *CHEMICAL synthesis , *MOIETIES (Chemistry) , *POLYMERIZATION - Abstract
In this article, well-defined cyclic amphiphilic random copolymers bearing azobenzene side chains and pendent carboxyl moieties, cyclic-P(BHME m- co-AA n)s, are synthesized by combining atom transfer radical polymerization (ATRP) with Cu(I)-catalyzed azide/alkyne cycloaddition (CuAAC) 'click' reaction and selective hydrolysis of tert-butyl ester. Successful synthesis of the cyclic-P(BHME m- co-AA n)s is fully characterized and verified via conventional gel permeation chromatography, triple detection gel permeation chromatography, nuclear magnetic resonance, Fourier transform infrared, and matrix-assisted laser desorption ionization-time-of-flight mass spectrometry. The cyclic topology induces profound effects on the glass transition temperatures, self-assembly behavior, and photoresponsive performance of the copolymers compared with their linear counterparts. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
14. Cyclic Side-Chain Phenylazo Naphthalene Polymers: Enhanced Fluorescence Emission and Surface Relief Grating Formation.
- Author
-
Zhang, Hao, Zhou, Nianchen, Zhu, Xing, Chen, Xinrong, Zhang, Zhengbiao, Zhang, Wei, Zhu, Jian, Hu, Zhijun, and Zhu, Xiulin
- Abstract
Well-defined cyclic-polymers ( cyclic-PAzoMMAs), bearing side-chain phenylazo naphthalene chromophore, were successfully synthesized by the combination of atom transfer radical polymerization (ATRP) and copper(I)-catalyzed azide/alkyne cycloaddition 'click' reaction, as verified by GPC, 1H NMR, FTIR, and MALDI-TOF mass spectrometry. The cyclic-PAzoMMA showed higher glass transition temperatures than the linear-PAzoMMA with the same molecular weight. Interestingly, the cyclic-PAzoMMA exhibited deeper modulation depth (M.D.) induced by SRG, larger value of the photoinduced birefringence, increased fluorescence emission, and longer fluorescence lifetime in comparison with its linear counterpart. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
15. Synthesis of novel side-chain triphenylamine polymers with azobenzene moieties via RAFT polymerization and investigation on their photoelectric properties.
- Author
-
Sun, Yan, Zhou, Nianchen, Zhang, Wei, Li, Yaowen, Cheng, Zhenping, Zhu, Jian, Zhang, Zhengbiao, and Zhu, Xiulin
- Abstract
Two novel and well-defined polymers, poly[6-(5-(diphenylamino)-2-((4-methoxyphenyl)diazenyl)phenoxy)hexyl methacrylate] (PDMMA) and poly[6-(4-((3-ethynylphenyl)diazenyl) phenoxy)hexyl methacrylate] (PDPMMA), which bear triphenylamine (TPA) incorporated to azobenzene either directly (PDMMA) or with an interval (PDPMMA) as pendant groups were successfully prepared via reversible addition-fragmentation chain transfer polymerization technique. The electrochemical behaviors of PDPMMA and PDMMA were investigated by cyclic voltammograms (CV) measurement. The hole mobilities of the polymer films were determined by fitting the J-V (current-voltage) curve into the space-charge-limited current method. The influence of photoisomerization of the azobenzene moiety on the behaviors of fluorescence emission, CV and hole mobilities of these two polymers were studied. The fluorescent emission intensities of these two polymers in CH2Cl2 were increased by about 100 times after UV irradiation. The oxidation peak currents ( IOX) of the PDMMA and PDPMMA in CH2Cl2 were increased after UV irradiation. The photoisomerization of the azobenzene moiety in PDMMA had significant effect on the electrochemical behavior, compared with that in PDPMMA. The changes of the hole mobility before and after UV irradiation were very small for both polymers. The HOMO energies ( EHOMO, HOMO: the highest occupied molecular orbital) of side chain moieties of TPA incorporated with cis-isomer and trans-isomer of azobenzene in PDMMA and PDPMMA were obtained by theoretical calculation, which are basically consistent with the experimental results. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.