Novel triblock copolymers comprising a polyrotaxane middle block flanked by PNIPAAm blocks showing both thermo- and solvent-response

Wang, Jin; Ye, Lin; Zhang, Aiying; Feng, Zeng‐guo

doi:10.1039/c0jm02803g

Cited by 30 publications

(25 citation statements)

References 29 publications

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“…They have truncated-cone structures, with which the inside is hydrophobic while the outside is hydrophilic. Based [ on the porous structure and properties, cyclodextrins can form plenty of functional structures using host-guest self-assembly, hydrophobic-hydrophobic interaction or chemical modification, which have been widely used in the supramolecular chemistry to build well-defined self-assembly structures, [35][36][37][38][39][40][41] even been used as building blocks to synthesize molecular tubes [42] and hierarchical porous materials. [43] Another cyclodextrin-based porous structure is induced in specific solvent using lower critical solution temperature behavior (LCST), for example in hot DMF, which is discovered and will be discussed in this paper.…”

Section: Introductionmentioning

confidence: 99%

Recyclable Nanoporous Materials with Ordered Tunnels Self‐Assembled from α‐ and γ‐Cyclodextrins

Wang

Ye³

et al. 2019

ChemNanoMat

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A straightforward method to create nanoporous materials via the self‐assembly of macrocyclic molecules (MCMs) is proposed and fulfilled by using cyclodextrins (CD) as building blocks. Due to molecular geometry, α‐CD forms a hexagonal nanoporous crystal, whereas γ‐CD forms a cuboid crystal. The resulting products are confirmed by FTIR, 1H NMR and solid‐state 13C NMR to be solely built up by CDs. Well‐defined and monodisperse nano‐tunnels are formed in nanoporous materials by the template‐free, face‐to‐face self‐assembly of CDs, with diameters around 0.8 or 0.5 nm equal to the diameter of the CD cavities. Moreover, the nanoporous structure of the CD is reversible controlled simply by switching temperature in DMF, indicating that the nanoporous CDs could be recyclable used and recovered. These characteristic properties and behaviors of the nanoporous CDs made them to be an ideal green material for absorption, separation as well as CD recovery.

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Section: Introductionmentioning

confidence: 99%

Recyclable Nanoporous Materials with Ordered Tunnels Self‐Assembled from α‐ and γ‐Cyclodextrins

Wang

Ye³

et al. 2019

ChemNanoMat

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“…However, since the intermolecular π–π stack was broken in DMSO, LCPR cannot form the lyotropic LC structure as same as its thermotropic LC structure. In our previous study, it was found PR compound can form mosaic crystalline structure in DMF solution by virtue of the mobility of threaded CDs . As well know, PR usually possessed channel‐like crystalline structure in solid state, however this structure was destructed in polar solvent due to the breaking of hydrogen bond so that threaded CDs were endowed with entire mobility of free sliding and rotating along the main chain.…”

Section: Resultsmentioning

confidence: 99%

The Synthesis and Characterization of Spacer-Free Liquid Crystal Polyrotaxane by Virtue of the Mobility of Threaded α-Cyclodextrins

Guo

Yan

et al. 2016

Macromol. Chem. Phys.

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A novel spacer‐free liquid crystalline polyrotaxane (LCPR) is synthesized by directly grafting 4‐phenylazobenzoyl chloride onto the hydroxyl of threaded α‐cyclodextrin (α‐CD) as the side‐chain. It is found that LCPR can form nematic LC phase above 180 °C or under the concentration of 5–0.2 wt% in dimethyl sulfoxide (DMSO) solution. The mechanisms of formation of thermotropic and lyotropic LC phase are proposed, respectively, which show the mobility of both threaded α‐CDs and substituted azo‐mesogens is responsible for the formation of LC phase. This mechanism is further demonstrated by the formation of crystalline phase under UV radiation, which is characterized by polarizing optical microphotograph and UV measurements.

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“…It suggests that the β-CDs entrapped in the DMF treated PR samples are randomly dispersed along the polymer backbone, while those in the water treated ones are densely stacked on the polymer chain to form a typical channeltype crystal structure as schematized in Fig. 1(b) [13][14][15][16].…”

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confidence: 96%

“…It suggests that the change in the absorption intensity between the peaks at 1153 and 1025 cm -1 would stem from different self-assembled structures of β-CDs entrapped on the polymer backbone as previously reported [13,[15][16]. Consequently, the absorption intensity values of peaks at 1153 and 1025 cm -1 were used to deduce the following parameters:…”

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confidence: 98%

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Distinguishing channel-type crystal structure from dispersed structure in β-cyclodextrin based polyrotaxanes via FTIR spectroscopy

Wang

Gao

et al. 2011

Front. Mater. Sci.

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Combining with XRD analysis, Fourier transform infrared (FTIR) spectroscopy is employed to discern the self-assembled structures of β-cyclodextrins (β-CDs) threaded onto the polymer backbone in the polyrotaxanes (PRs) by means of the relative changes of absorption intensity of the characteristic peaks of β-CDs at 1153 and 1025 cm -1 . For quantitative analysis, six parameters are proposed to describe the relative absorption intensity variations of these peaks associated with a channel-type crystal structure or a dispersed structure of β-CDs entrapped. Among them, absorbance ratio (AR), relative absorbance difference (RAD) and transmittance difference (TD) values are suitable. When the AR, RAD and TD data get below 1.04, 4.8 and 1.27, respectively, the PRs obtained would possess a dispersed structure. If these values go beyond 1.32, 34.5 and 9.47, respectively, they would hold a channel-type crystal structure. This finding provides a useful judgment to distinguish the self-assembled structures of β-CDs residing along the polymer backbone in the PRs.

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Novel triblock copolymers comprising a polyrotaxane middle block flanked by PNIPAAm blocks showing both thermo- and solvent-response

Cited by 30 publications

References 29 publications

Recyclable Nanoporous Materials with Ordered Tunnels Self‐Assembled from α‐ and γ‐Cyclodextrins

Recyclable Nanoporous Materials with Ordered Tunnels Self‐Assembled from α‐ and γ‐Cyclodextrins

The Synthesis and Characterization of Spacer-Free Liquid Crystal Polyrotaxane by Virtue of the Mobility of Threaded α-Cyclodextrins

Distinguishing channel-type crystal structure from dispersed structure in β-cyclodextrin based polyrotaxanes via FTIR spectroscopy

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