Dielectric relaxation of liquid-crystalline polyrotaxane

Inomata, Aoi; Ishibashi, Hitoshi; Nakajima, Takao; Sakai, Yasuhiro; Kidowaki, Masatoshi; Shimomura, Takeshi; Ito, Kohzo

doi:10.1209/0295-5075/79/66004

Cited by 18 publications

(22 citation statements)

References 29 publications

(30 reference statements)

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“…[36] It is noticeable that the presence of PPy improved the E β value of 3b (56 kJ mol −1 ) confirming the physical interactions of PPy polymer with polyrotaxane chains that influence the molecular mobility of chain segments of the supramolecular network. [37,38] The result was also in good correlation with SEM analysis in which a material with a porous morphology and intertwined nanofibers was identified.…”

Section: Samplesupporting

confidence: 63%

Morphological and Electronic Properties of Poly(ethylene glycol)/RAMEB Polyrotaxane and Polypyrrole Supramolecular Networks

Resmeriță¹,

Asăndulesa²,

Farcas³

2020

Macro Chemistry & Physics

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well their mechanical properties. The crosslinked polyrotaxanes are characterized by high mobility of the junctions, which considerably diminished the internal tension when a stimulus is applied, providing the enhancements of mechanical properties. [6][7][8][9][10][11] The blending of the CPs into the matrix, in one step reaction, leads to a more homogeneous network compounds. Recently, our efforts are being made in this directions and a versatile synthetic strategy was applied for the synthesis of such supramolecular networks by cross-linking of an insulated polyrotaxane with π-conjugated polyrotaxanes. [12] Due to controllable electrical conductivity and good thermal stability of polypyrrole (PPy), this approach has also been applied to the synthesis of composite materials based on PEGBA polyrotaxane with randomly methylated β-cyclodextrins (RAMEB). [13][14][15] Herein, we report the synthesis and characterization of a new composite material obtained by cross-linking of PEGBA/RAMEB polyrotaxane with 1,6-hexamethylene diisocyanate (HMDI). The addition of 10 wt% PPy into the PEGBA/RAMEB matrix showed improved physical, morphological as well electrical properties of the resulted cross-linked material. Moreover, the influences of the temperature and frequency on the electrical properties of the investigated PEGBA/RAMEB/PPy compound were investigated and compared with those of the pure PEGBA/RAMEB crosslinked material.The effect of 10 wt% polypyrrole (PPy) incorporation on the evolution of conductivity, dielectric constant, and dielectric loss by varying the temperature and frequency of amine-terminated poly(ethylene glycol)/randomly methylated β-cyclodextrins (PEGBA/RAMEB) polyrotaxane cross-linked with 1,6-hexamethylene diisocyanate is reported. This composite material shows an enhanced dielectric constant value of 25.6 (at 10 Hz) compared with 8.3 of the pure cross-linked PEGBA/RAMEB polyrotaxane. The values of the dielectric constant are consistent with the dielectric loss and conductivity results. The composite material shows that the direct current conductivity (σ DC ) at lower temperature is independent of frequency. In comparison, at higher temperature, σ DC is dependent on frequency, denoting that the conductivity of the composite material is a thermally activated process. Moreover, the presence of PPy significantly influences the morphology of the cross-linked PEGBA/RAMEB polyrotaxane. Addition of PPy into PEGBA/RAMEB material seems to be very attractive and should provide an opportunity to obtain desirable electronic properties.

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Section: Samplesupporting

confidence: 63%

Morphological and Electronic Properties of Poly(ethylene glycol)/RAMEB Polyrotaxane and Polypyrrole Supramolecular Networks

Resmeriță¹,

Asăndulesa²,

Farcas³

2020

Macro Chemistry & Physics

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“…Ion-active Functional liquid-crystalline polymers T Kato et al polymers, 82,83 which provides potential applications for new stimuliresponsive materials. Main-chain LC polyrotaxanes were synthesized by polymerization of pseudorotaxane monomers prepared by intramolecular self-inclusion.…”

Section: Supramolecular Design Of Lc Polymersmentioning

confidence: 99%

Functional liquid-crystalline polymers and supramolecular liquid crystals

Kato

Uchida

Ichikawa

et al. 2017

Polym J

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The design and functions of liquid-crystalline (LC) polymers with classifying them into conventional-, supramolecular-, dendriticand network-type LC polymers are described. LC polymers show new functions as new devices in the field of energy and environment by incorporating mesogenic moieties exhibiting photonic, electronic and ionic functions. Supramolecular LC polymers show dynamic and unique properties because the mesogenic moieties are built with non-covalent interactions. Dendritic-type LC polymers exhibit liquid crystallinity by nanosegregation of aromatic and aliphatic moieties. Dendritic fork-like mesogens have also been prepared. A variety of nonmesogeic functional building blocks including fullerene, π-conjugated moieties, catenane, rotaxane and others can be incorporated into LC phases by attaching these dendritic moieties. LC networks are constructed in situ polymerization of polymerizable nematic or nanostructured liquid crystals. The specific characteristics of the LC networks have generated new research trends to develop well-defined polymers that exhibit optical, transport and separation properties. In these materials, through suitable design of LC monomers, the preservation of smectic, columnar and bicontinuous cubic phases has been successfully used for the development of membranes with one-dimensional, two-dimensional and three-dimensional nanostructures.

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“…Wide‐angle X‐ray diffraction patterns also suggest that this polymer shows a nematic phase. Molecular fluctuations in 8 have been investigated by dielectric relaxation measurements 21b,c. The rotational mode of the cyanobiphenyl mesogenic groups around the short axis is observed in the nematic phase.…”

Section: Liquid‐crystalline Polyrotaxanesmentioning

confidence: 99%

Liquid‐Crystalline Catenanes and Rotaxanes

Sakuda

Yasuda

Kato

2012

Israel Journal of Chemistry

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Catenanes and rotaxanes are mechanically interlocked molecules. For further functionalization, the introduction of such molecules into ordered fluid states is of interest. The control of their dynamic properties in liquid‐crystalline order may lead to the development of new smart soft materials such as stimuli‐responsive materials and molecular machines. In this review, thermotropic and lyotropic liquid‐crystalline catenanes and rotaxanes are described. One approach to the induction of liquid crystallinity to [2]catenanes and [2]rotaxanes is the attachment of mesogenic moieties. Rigid‐rod polyrotaxanes that behave as mesogens also exhibit liquid‐crystalline properties.

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Dielectric relaxation of liquid-crystalline polyrotaxane

Cited by 18 publications

References 29 publications

Morphological and Electronic Properties of Poly(ethylene glycol)/RAMEB Polyrotaxane and Polypyrrole Supramolecular Networks

Morphological and Electronic Properties of Poly(ethylene glycol)/RAMEB Polyrotaxane and Polypyrrole Supramolecular Networks

Functional liquid-crystalline polymers and supramolecular liquid crystals

Liquid‐Crystalline Catenanes and Rotaxanes

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