Atomic force microscopy on tree-like crystals in polyvinylidene fluoride blends

Lima, Maria Alice Dias da Silva; Magonov, S. N.; Hellmann, E. H.; Jacobs, Martin I.; Crämer, K.

doi:10.1023/a:1004387304385

Cited by 18 publications

(8 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…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: 97%

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

Zhang

et al. 2017

Crystals

View full text Add to dashboard Cite

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...

show abstract

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

confidence: 97%

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

Zhang

et al. 2017

Crystals

View full text Add to dashboard Cite

show abstract

“…5, the lamellas start growing from a nucleus of a crystal. A slow diffusion leads to tree-like architecture of branches and twigs with built-in depletion zones [20]. PVDF are shown in Figs.…”

Section: Ftir Study Of the Pvdf And Pvdf/pzt-npsmentioning

confidence: 99%

Experimental and theoretical dielectric studies of PVDF/PZT nanocomposite thin films

Zak

Gan

Majid

et al. 2011

Ceramics International

137

View full text Add to dashboard Cite

“…[11][12][13][14][15][16]85 The system fulfills not only the necessary presuppositions. Both components crystallize readily (PVDF, [97][98][99] and PHB 23,100,101 ). The individual crystallization behavior of the two polymers is well investigated, too, and can serve as a reference for the behavior in the blend.…”

Section: Htc/ncc Systems: Crystallization Induced Composition Changesmentioning

confidence: 99%

Crystallization kinetical and morphological peculiarities in binary crystalline/crystalline polymer blends

Liu

Jungnickel

2007

J Polym Sci B Polym Phys

View full text Add to dashboard Cite

A survey is presented on the crystallization kinetics and the morphology of miscible crystalline/crystalline polymer blends. There are only few corresponding systems. In them, however, a number of strange kinetic and structural phenomena can be observed: (i) spherulitic crystallization of the components side‐by‐side, (ii) “interpenetrating crystallization,” (iii) “interlocking spherulitic crystallization,” and (iv) “interfilling crystallization.” Cocrystallization is forbidden for crystallographic reasons. The blend partners grow instead in their own lamellar stacks, and mixed lamellar stacks are a seldom and questionable exception. They crystallize also usually stepwise and not simultaneously. Upon step crystallization, the crystallization of the second component is determined by its redistribution with crystallization of the former. Those composition inhomogeneities are an independent issue that arises also with the development of the morphology in crystalline/amorphous blends, and a corresponding survey is yielded, too. The blend poly (vinylidene fluoride)/poly‐β‐hydroxybutyrate is a convenient model system as it can show all of these morphological and kinetic features after suitable thermal treatment. Some of them are demonstrated in the present publication. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1917–1931, 2007

show abstract

Atomic force microscopy on tree-like crystals in polyvinylidene fluoride blends

Cited by 18 publications

References 16 publications

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

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

Experimental and theoretical dielectric studies of PVDF/PZT nanocomposite thin films

Crystallization kinetical and morphological peculiarities in binary crystalline/crystalline polymer blends

Contact Info

Product

Resources

About