Liquid crystalline order in solutions of rigid-chain polymers

Papkov, S. P.

doi:10.1007/3-540-12818-2_7

Cited by 61 publications

(10 citation statements)

References 41 publications

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“…The introduction of acetyl groups effectively destroys the hydrogen bonding networks. However, due to the small volume of acetyl groups and the inherent rigidity of cellulose backbones, − the thermal motion of macromolecular chains is still poor; thus, CA-2.92 would not flow without external plasticizers. In contrast, after a bulky pendant group, like α-naphthoate, is introduced into the cellulose chain, the distance between the macromolecular chains increases significantly, and as a result, the free volume and mobility of the molecular chains is improved.…”

Section: Resultsmentioning

confidence: 99%

Novel Thermoplastic Cellulose Esters Containing Bulky Moieties and Soft Segments

Chen

Zhang

Xiao

et al. 2018

ACS Sustainable Chem. Eng.

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It is still challenging to convert cellulose into melt-processable materials because natural cellulose, which has a strong hydrogen bonding network, degrades before melting. Herein, a series of novel cellulose-based thermoplastics were successfully designed and fabricated by a simple and efficient homogeneous esterification of cellulose in an ionic liquid. Introducing ester substituents containing both bulky moieties and soft segments can improve the mobility of the cellulose chain, and the glass transition temperatures (T gs) appeared in the resultant cellulose esters. In particular, when the ester substituents consisted of bulky terminal moiety and soft middle segment, T gs of the corresponding cellulose esters were relatively low (80–160 °C), indicating these cellulose materials were suitable for melt processing. Accordingly, these thermoplastic cellulose esters can be processed into transparent disks, dumbbells, fibers and flexible films by traditional injection molding, melt extrusion, and hot pressing without any external plasticizers. Therefore, this work provides a simple and engineering method to construct melt-processable bioplastics from cellulose.

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Section: Resultsmentioning

confidence: 99%

Novel Thermoplastic Cellulose Esters Containing Bulky Moieties and Soft Segments

Chen

Zhang

Xiao

et al. 2018

ACS Sustainable Chem. Eng.

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“…For this value, it is predicted to lack the critical and triple points expected for longer molecules (Khokhlov and Semenov, 1985;Warner and Flory, 1980). We superposed on this diagram the coexistence curve for the classical amorphous phase separation (Flory, 1953;Post and Zimm, 1982;Papkov, 1984). Path I illustrates the formation of liquid crystals in the presence of repulsive interactions, obtained by increasing DNA concentration.…”

Section: Interpretation Of the Results In The Context Of Flory's Theorymentioning

confidence: 99%

A liquid crystalline phase in spermidine-condensed DNA

Sikorav¹,

Pelta²,

Livolant³

1994

Biophysical Journal

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Over a large range of salt and spermidine concentrations, short DNA fragments precipitated by spermidine (a polyamine) sediment in a pellet from a dilute isotropic supernatant. We report here that the DNA-condensed phase consists of a cholesteric liquid crystal in equilibrium with a more concentrated phase. These results are discussed according to Flory's theory for the ordering of rigid polymers. The liquid crystal described here corresponds to an ordering in the presence of attractive interactions, in contrast with classical liquid crystalline DNA. Polyamines are often used in vitro to study the functional properties of DNA. We suggest that the existence of a liquid crystalline state in spermidine-condensed DNA is relevant to these studies.

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“…As such, increasing the nanomaterial surface charge (through increasing reduction stoichiometry or reducing p K a of a solubilizing superacid) not only enables the formation of LC phases but also increases the concentration window of the monophasic LC phase. At insufficient p K a in superacid, a different phase (the so-called “crystal-solvate”) forms, with solvent molecules ordered between the aligned SWCNTs, analogously to an intercalation compound. The short-range repulsion can also be increased for reduced CCNs through chelation of the counterion (section ) (Figure a) .…”

Section: Behavior Of Ccn Solutionsmentioning

confidence: 99%

Charged Carbon Nanomaterials: Redox Chemistries of Fullerenes, Carbon Nanotubes, and Graphenes

et al. 2018

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Since the discovery of buckminsterfullerene over 30 years ago, sp 2 -hybridised carbon nanomaterials (including fullerenes, carbon nanotubes, and graphene) have stimulated new science and technology across a huge range of fields. Despite the impressive intrinsic properties, challenges in processing and chemical modification continue to hinder applications. Charged carbon nanomaterials (CCNs), formed via the reduction or oxidation of these carbon nanomaterials, facilitate dissolution, purification, separation, chemical modification, and assembly. This approach provides a compelling alternative to traditional damaging and restrictive liquid phase exfoliation routes. The broad chemistry of CCNs not only provides a versatile and potent means to modify the properties of the parent nanomaterial but also raises interesting scientific issues. This review focuses on the fundamental structural forms: buckminsterfullerene, single-walled carbon nanotubes, and single-layer graphene, describing the generation of their respective charged nanocarbon species, their interactions with solvents, chemical reactivity, specific (opto)electronic properties, and emerging applications. CONTENTS

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Liquid crystalline order in solutions of rigid-chain polymers

Cited by 61 publications

References 41 publications

Novel Thermoplastic Cellulose Esters Containing Bulky Moieties and Soft Segments

Novel Thermoplastic Cellulose Esters Containing Bulky Moieties and Soft Segments

A liquid crystalline phase in spermidine-condensed DNA

Charged Carbon Nanomaterials: Redox Chemistries of Fullerenes, Carbon Nanotubes, and Graphenes

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