Shear-Induced Spiral-Like Morphology of a Main-Chain Liquid Crystalline Poly(aryl ether ketone)

Fu, Luxiang; Zhang, Shanju; Zhang, Jian; Liu, Jingjiang; Yang, Di

doi:10.1002/1521-3927(20011001)22:14<1168::aid-marc1168>3.0.co;2-9

Cited by 7 publications

(7 citation statements)

References 2 publications

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“…It is known that the LC-PAEK films display a typical mosaic texture, [13] a highly ordered liquid crystalline phase S E , while PEEK exhibits a spherulitic morphology. [14,15] However, in nonisothermally crystallized films of the LC-PAEK/ PEEK blends with a higher content (>50%) of LC-PAEK, a ring-banded spherulite is formed, which has never been found in the two pure components.…”

Section: Resultsmentioning

confidence: 99%

Nature of the Ring‐Banded Spherulites in Blends of Aromatic Poly(ether ketone)s

Chen¹,

Yang²

2004

Macromol. Rapid Commun.

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Summary: The ring‐banded spherulites in liquid crystalline poly(aryl ether ketone) (LC‐PAEK) and poly(aryl ether ether ketone) (PEEK) blends with a higher content (>50%) of LC‐PAEK are investigated by polarizing light microscopy (PLM) and atomic force microscopy (AFM) techniques. The results indicate that the light core and rings of the ring‐banded spherulites under PLM are mainly composed of an LC‐PAEK phase, while the dark rings consist of coexisting phases of PEEK and a small amount of LC‐PAEK. The formation of the ring‐banded spherulites is attributable to structural discontinuity caused by a rhythmic radial growth.PLM image of ring‐banded spherulites in a 70:30 LC‐PAEK/PEEK blend caused by rhythmic growth.magnified imagePLM image of ring‐banded spherulites in a 70:30 LC‐PAEK/PEEK blend caused by rhythmic growth.

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Section: Resultsmentioning

confidence: 99%

Nature of the Ring‐Banded Spherulites in Blends of Aromatic Poly(ether ketone)s

Chen¹,

Yang²

2004

Macromol. Rapid Commun.

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“…and biphenyl mesogenic units into the PAEK backbones. The main‐chain LC‐PAEKs exhibit complicated phase behavior, including nematic (N), smectic (S), smectic crystalline (SC), and crystalline (C) phases, and abundant LC textures, such as schlieren, fan‐shaped, shear‐induced focal conic, and spiral textures, as well as highly ordered liquid crystalline structures (S E phase), including monodomain, mosaic, and single crystal‐like banded textures 11–16. Obviously, there are remarkable dissimilarities between LC‐PAEKs and PAEKs, especially in the morphology, phase, and crystallization behavior.…”

Section: Introductionmentioning

confidence: 99%

Rhythmic growth of ring‐banded spherulites in blends of liquid crystalline methoxy‐poly(aryl ether ketone) and poly(aryl ether ether ketone)

Chen

Yang

2007

J Polym Sci B Polym Phys

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Rhythmic growth of ring‐banded spherulites in blends of liquid crystalline methoxy‐poly(aryl ether ketone) (M‐PAEK) and poly(aryl ether ether ketone) (PEEK) has been investigated by means of differential scanning calorimetry (DSC), polarized light microscopy (PLM), and scanning electron microscopy (SEM) techniques. The measurements reveal that the formation of the rhythmically grown ring‐banded spherulites in the M‐PAEK/PEEK blends is strongly dependent on the blend composition. In the M‐PAEK‐rich blends, upon cooling, an unusual ring‐banded spherulite is formed, which is ascribed to structural discontinuity caused by a rhythmic radial growth. For the 50:50 M‐PAEK/PEEK blend, ring‐banded spherulites and individual PEEK spherulites coexist in the system. In the blends with PEEK as the predominant component, M‐PAEK is rejected into the boundary of PEEK spherulites. The cooling rate and crystallization temperature have great effect on the phase behavior, especially the ring‐banded spherulite formation in the blends. In addition, the effects of M‐PAEK phase transition rate and phase separation rate on banded spherulite formation is discussed. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 3011–3024, 2007

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“…Atomic force microscopy (AFM) is a useful method for studying the microstructure at a high resolution. It has proved to be of great utility in the study of liquid crystalline polymers. − In the case of semicrystalline liquid crystalline polymers, crystalline lamellae, which are formed perpendicular to the local director, can be used to decorate molecular orientation, and the director trajectories around a disclination are, therefore, directly visualized via AFM. , This lamellar decoration technique to explore the director orientation in semicrystalline liquid crystalline polymers has been successfully applied for the analysis of the supermolecular microstructures of disclinations and inversion walls in main-chain liquid crystalline polymers by using AFM. ,, However, almost no observation of director fields of disclinations and inversion walls in side-chain amorphous liquid crystalline polymers has been reported to date …”

Section: Introductionmentioning

confidence: 99%

“…18,19 This lamellar decoration technique to explore the director orientation in semicrystalline liquid crystalline polymers has been successfully applied for the analysis of the supermolecular microstructures of disclinations and inversion walls in main-chain liquid crystalline polymers by using AFM. 14,18,19 However, almost no observation of director fields of disclinations and inversion walls in sidechain amorphous liquid crystalline polymers has been reported to date. In this work, we employ the stripe-decoration technique to study the director distortions around the disclinations and inversion walls in side-chain liquid crystalline polymers using AFM.…”

Section: Introductionmentioning

confidence: 99%

Atomic Force Microscopy Study for Supermolecular Microstructures in Side-Chain Liquid Crystalline Polymer Films

2005

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Atomic force microscopy (AFM) is employed to study the supermolecular microstructures of disclinations and inversion walls in thin films of a smectic side-chain liquid crystalline polymer. Two-dimensional nanostripes are formed in thin films when the material enters the smectic phase. A possible mechanism for their formation is also suggested. The stripes run parallel to the local director and thus decorate the overall patterns of nematic director around the disclinations and inversion walls. Three patterns involving radial, spiral, and circular supermolecular microstructures of a positive disclination with s = +1 and one hyperbolic pattern of a negative disclination with s = -1 are observed. The cores of all these microstructures exhibit circular dark centers in AFM height images. It is found that the specific configurations of a pair of (+1, -1) disclinations form during the late stage of annihilation and inversion walls always separate a pair of (+1, +1) disclinations. The analysis on the director fields around disclinations and inversion walls shows that the bend and splay elastic constants are of the same order of magnitude in the side-chain liquid crystalline polymer.

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Shear-Induced Spiral-Like Morphology of a Main-Chain Liquid Crystalline Poly(aryl ether ketone)

Cited by 7 publications

References 2 publications

Nature of the Ring‐Banded Spherulites in Blends of Aromatic Poly(ether ketone)s

Nature of the Ring‐Banded Spherulites in Blends of Aromatic Poly(ether ketone)s

Rhythmic growth of ring‐banded spherulites in blends of liquid crystalline methoxy‐poly(aryl ether ketone) and poly(aryl ether ether ketone)

Atomic Force Microscopy Study for Supermolecular Microstructures in Side-Chain Liquid Crystalline Polymer Films

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