Synthesis, self-assembly and photo-responsive behavior of AB2 shaped amphiphilic azo block copolymer

Wei, Renbo; Wang, Xiaogong; He, Yaning

doi:10.1016/j.cclet.2015.04.019

Cited by 12 publications

(6 citation statements)

References 38 publications

(44 reference statements)

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“…Although the exact mechanism has not yet been fully understand, the photo-induced isomerization of azobenzene is believed to play a key role in the light-driven process. In this study, the polarized LED light was used to investigate the photo-induced deformation of the aggregates, the samples are perpendicularly irradiated with 365 nm polarized light (60 mW cm 22 ). After the irradiation for 6 h, the aggregates are obviously elongated along the polarization direction of the polarizer [ Figure 7(b)], with an average major-tominor axis ratio (l/d) of 1.5 6 0.3.…”

Section: Article Wileyonlinelibrarycom/appmentioning

confidence: 99%

“…Then the aggregates together with the copper grids were dried in a vacuum oven at room temperature for 20 h. After that, the sample was irradiated by polarized light at the wavelength of 365 nm (6 h, LED lamp, 60 mW cm 22 ) to investigate the photo-induced deformation of the aggregates. The UV light was incident perpendicularly to the surface of the grids under an ambient condition at room temperature.…”

Section: Photo-induced Shape Deformationmentioning

confidence: 99%

“…A similar result was reported before. 22 The self-assembly of P6OCN 16 -b-2PEG 43 is studied by adding deionized water into its THF solution. First, homogeneous solution of P6OCN 16 -b-2PEG 43 (0.3 mg mL 21 ) is prepared by dissolving it in anhydrous THF.…”

Section: Article Wileyonlinelibrarycom/appmentioning

confidence: 99%

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Synthesis, characterization, and photo‐responsive properties of Y‐shaped amphiphilic azo triblock copolymer

Wei

Zhang

et al. 2016

J of Applied Polymer Sci

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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 1 H 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.

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Section: Article Wileyonlinelibrarycom/appmentioning

confidence: 99%

Section: Photo-induced Shape Deformationmentioning

confidence: 99%

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Synthesis, characterization, and photo‐responsive properties of Y‐shaped amphiphilic azo triblock copolymer

Wei

Zhang

et al. 2016

J of Applied Polymer Sci

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“…Depending on the mesogenic units in the polymer, liquid crystalline polymers are divided into main-and side-chain liquid crystalline polymers [21][22][23][24][25]. The side-chain liquid crystalline polymers are further divided into 'side-on' and 'end-on' types depending on whether the mesogenic groups are attached laterally or terminally to the polymer backbone via a flexible spacer [26,27]. For liquid crystalline polymers with the 'end-on' structure, they usually tend to form smectic phases [27,28], while the nematic phase is usually obtained in 'side-on' liquid crystalline polymer [29,30].…”

Section: Introductionmentioning

confidence: 99%

Synthesis, liquid crystalline mesophases and morphologies of diblock copolymers composed of a poly(dimethylsiloxane) block and a nematic liquid crystalline block

Wei

Ma²,

Zhang

et al. 2016

Liquid Crystals

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In this study, a series of liquid crystalline diblock copolymers, composed of a soft poly(dimethylsiloxane) (PDMS) block with a defined length and a side-on liquid crystalline poly(3ʹʹ-acryloyloxypropyl 2,5-di(4ʹ-butyloxybenzoyloxy) benzoate) (P3ADBB) block with different lengths, are synthesised by the atom transfer radical polymerisation. The macromolecular structures, liquid crystalline properties and the microphase-separated morphologies of the diblock copolymer are investigated by 1 H NMR, FT-IR, GPC, POM, DSC and TEM. The results show that the well-defined diblock copolymers (PDMS n -b-P3ADBB m ) possess four different soft/rigid ratios (n = 58, m = 10, 25, 42, 66) and relatively narrow molecular distributions (PDI ≤ 1.30). P3ADBB blocks of the copolymers show nematic sub-phases, which are identical to the mesomorphic behaviour of the homopolymer P3ADBB. After being annealed at 90°C in a vacuum oven for 48 h, the copolymers form a lamellar morphology when m = 10 and morphologies of PDMS spheres embedded in P3ADBB matrix when m = 25, 42 and 66. ARTICLE HISTORY

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“…Azobenzene can be divided as the aminoazobenzene, azobenzene branch, and pseudo-stilbene branch based on their isomerization behavior and spectral feature [21,22]. Due to the mesogenic property of azobenzene, the azobenzene branch usually displays liquid crystalline features [23,24,25,26]. As a consequence, such kind of azobenzene tends to exhibit higher photoinduced anisotropy when exposed to polarized light.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Photoinduced Anisotropy of Polymers Containing Nunchaku-Like Unit with an Azobenzene and a Mesogen

et al. 2019

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A series of polymers containing nunchaku-like unit with an azo chromophore and a mesogen group was successfully prepared and photoinduced anisotropy of the obtained polymers was minutely investigated. Firstly, monomers containing nunchaku-like unit with an azo chromophore and a mesogen group linked by flexible group were synthesized. The structure of the monomers was confirmed via NMR COSY spectra. Subsequently, the obtained monomers were polymerized into corresponding polymers through RAFT polymerization. The prepared polymer samples were characterized through NMR, FTIR, gel permeation chromatography (GPC), and UV-vis testing while the thermal properties of the samples were investigated through differential scanning calorimeter (DSC) and thermogravimetric analysis (TGA) measurements. The photoinduced isomerization of the polymers, which was researched in situ via measuring UV-vis spectra of the polymer solutions and spin-coated films under irradiation with 450 nm light or putting in darkness, demonstrated the rapid trans-cis-trans isomerization of the polymers. When irradiated with a linearly polarized light, significant photoinduced birefringence and dichroism were observed, suggesting photoinduced isomerization of azobenzene can drive orientation of mesogen in the system. This study blazes a way to design the optical materials with light-controllable birefringence and dichroism.

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Synthesis, self-assembly and photo-responsive behavior of AB2 shaped amphiphilic azo block copolymer

Cited by 12 publications

References 38 publications

Synthesis, characterization, and photo‐responsive properties of Y‐shaped amphiphilic azo triblock copolymer

Synthesis, characterization, and photo‐responsive properties of Y‐shaped amphiphilic azo triblock copolymer

Synthesis, liquid crystalline mesophases and morphologies of diblock copolymers composed of a poly(dimethylsiloxane) block and a nematic liquid crystalline block

Synthesis and Photoinduced Anisotropy of Polymers Containing Nunchaku-Like Unit with an Azobenzene and a Mesogen

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