Morphological development of melt crystallized poly(propylene oxide) by in situ AFM: formation of banded spherulites

Beekmans, L.G.M.; Hempenius, Mark A.; Vancso, Gyula J.

doi:10.1016/j.eurpolymj.2004.01.025

Cited by 22 publications

(9 citation statements)

References 33 publications

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“…Ring structures in crystalline polymers have been discovered and studied for a long time 1–3. Ring‐banded morphology is commonly seen in some crystalline polymers4–7 or in blends of crystalline polymers with other crystalline or amorphous polymers 8–12. The mechanism and formation of the ring bands have been an interesting and intriguing subject in numerous studies for decades.…”

Section: Introductionmentioning

confidence: 99%

Annular Multi‐Shelled Spherulites in Interiors of Bulk‐Form Poly(nonamethylene terephthalate)

Chen

Woo

2009

Macromol. Rapid Commun.

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Morphology of crystallized spherulites in poly(nonamethylene terephthalate) (PNT) in bulk forms, instead of thin-film forms, was investigated using scanning electron microscopy (SEM), polarized-optical microscopy (POM), and transmission electron microscopy (TEM). Ring textures were found to exist on the fractured surfaces or microtomed films from bulk PNT samples. By further SEM and TEM examinations, the fracture surfaces and microtomed films from the interior of the bulk display similar ring-banded patterns as those in thin films cast on glass slides. Although the cast PNT thin films in two-dimensional growth are known to display both Type-1 ring bands as majority and Type-2 ring bands as minority, this study further shows that the interior of PNT bulk exhibits mainly Type-1 (single rings with narrower spacing than Type-2) ring bands, and Type-2 spherulites exist sporadically in three-dimensional forms. From these analyses on the ring bands in the interiors of bulk-form PNT crystallized at several specific temperatures, it can be proposed that the growth of spherulites in three dimensions is layer-by-layer, packing into a multi-shells structure in three-dimensional ring-banded spheres.

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Section: Introductionmentioning

confidence: 99%

Annular Multi‐Shelled Spherulites in Interiors of Bulk‐Form Poly(nonamethylene terephthalate)

Chen

Woo

2009

Macromol. Rapid Commun.

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“…Previous SEM [20,21], TEM [22,23], and AFM observations [24][25][26] have demonstrated that the banded polymer spherulites consist of alternative edge-on and flat-on oriented lamellar crystals. However, due to the close packing of the dense lamellae, the lamellar twisting details had not been clearly revealed before the real-time AFM observations [27].…”

Section: Real Time Atomic Force Microscopy (Afm) Observation Reveals mentioning

confidence: 99%

Organization of Twisting Lamellar Crystals in Birefringent Banded Polymer Spherulites: A Mini-Review

Zhang

et al. 2017

Crystals

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Abstract:In this mini-review, we summarize the evidences of lamellar twisting in the birefringent banded polymer spherulites demonstrated by various characterization techniques, such as polarized optical microscopy, real-time atomic force microscopy, micro-focus wide angle X-ray diffraction, etc. The real-time observation of lamellar growth under atomic force microscopy unveiled the fine details of lamellar twisting and branching in the banded spherulites of poly(R-3-hydroxybutyrate-co-17 mol % R-3-hydroxyhexanoate). Organization of the twisting lamellar crystals in the banded spherulites was revealed as well. The lamellar crystals change the orientation via twisting rather than the macro screw dislocations. In fact, macro screw dislocation provides the mechanism of synchronous twisting of neighboring lamellar crystals. The driving force of lamellar twisting is attributed to the anisotropic and unbalanced surface stresses. Besides molecular chirality, variation of the growth axis and the chemical groups on lamellar surface can change the distribution of the surface stresses, and thus may invert the handedness of lamellar twisting. Thus, based on both experimental results and physical reasoning, the relation between crystal chirality and chemical molecular structures has been suggested, via the bridge of the distribution of surface stresses. The factors affecting band spacing are briefly discussed. Some remaining questions and the perspective of the topic are highlighted.Keywords: banded polymer spherulite; ringed spherulite; lamellar twisting; organization of lamellar crystals; surface stresses; chirality When crystallized from quiescent melt or concentrated solution, polymer chains usually form spherulites consisted of multiple lamellar crystals radiating from the spherulite center. Observed under polarized optical microscope (POM), a spherulite shows the characteristic Maltese-cross extinction. Besides the Maltese cross, some spherulites demonstrate alternative bright and dark bands under POM. These spherulites are termed as banded spherulites or ringed spherulites. The band structure with different light intensities may result from different thicknesses or different birefringences but similar thickness. In the former case, the bands are due to the periodical modulation of sample thickness and there is no variation of refractive index in the spherulite. These nonbirefringent banded spherulites have been observed in some polymer single crystals formed from thin melt films [1] or solutions [2] and are reviewed by Li et al. [3] in this special issue. In the latter case, the birefringent bands can result from the wavy bending growth or twisting growth of crystals. The wavy bands have been reported in sheared liquid crystals [4,5], which do not form spherulites under the condition. In this mini-review, we focus on the birefringent banded spherulites, which consist of synchronously twisted lamellar crystals. The organization of the twisted lamellar crystals in the banded spherulites and the driving force for lamell...

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“…To cite but a few, AFM imaging was performed on the crystallization process of poly(propylene oxide) from the melt [35] and during annealing and melting of single crystals of polyethylene [36,37] and long n-alkanes, [38] respectively, to follow details of the morphological changes.…”

Section: Imaging Of Processesmentioning

confidence: 99%

The Art of SPM: Scanning Probe Microscopy in Materials Science

Loos

2005

Advanced Materials

102

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In this Progress Report, outstanding scientific applications of scanning probe microscopy (SPM) in the field of materials science and the latest technique developments are introduced and discussed. Besides being able to image the organization of matter with sub‐nanometer resolution, SPM, owing to its basic operating principle, provides the power to measure, analyze, and even quantify properties of matter on the nanometer length scale. Moreover, because of its unique potential to manipulate the organization of atoms, molecules, assemblies, or particles and to structure surfaces in a controlled fashion, in the fields of nanoscience and nanotechnology SPM has become one of the most powerful tools for preparation and analysis of nanostructures and their functionality. Because of the tremendous variety of its applications, only selected—but subjectively exceptional—topics are considered in this Progress Report, showing the full potential of SPM.

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Morphological development of melt crystallized poly(propylene oxide) by in situ AFM: formation of banded spherulites

Cited by 22 publications

References 33 publications

Annular Multi‐Shelled Spherulites in Interiors of Bulk‐Form Poly(nonamethylene terephthalate)

Annular Multi‐Shelled Spherulites in Interiors of Bulk‐Form Poly(nonamethylene terephthalate)

Organization of Twisting Lamellar Crystals in Birefringent Banded Polymer Spherulites: A Mini-Review

The Art of SPM: Scanning Probe Microscopy in Materials Science

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