Analysis of crystal assembly in banded spherulites of phthalic acid upon solvent evaporation

Woo, Eamor M.; Lugito, Graecia; Yang, Cheng En

doi:10.1039/c5ce02043c

Cited by 28 publications

(29 citation statements)

References 34 publications

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“…Crystals in nonpolymeric compounds, such as low‐molecular‐weight (LM w ) organic hippuric acid, d ‐mannitol, phthalic acid, aspirin, and testosterone propionate, compounds as well as inorganic salt potassium dichromate (K 2 Cr 2 O 7 ) crystals may also exhibit periodic banded patterns during crystallization. For small molecules, there are two proposals considering the formation of banded spherulites: (1) helical crystals and (2) rhythmic precipitation.…”

Section: Introductionmentioning

confidence: 99%

Periodic extinction bands composed of all flat‐on lamellae in poly(dodecamethylene terephthalate) thin films crystallized at high temperatures

Lugito

Woo

Chang

2017

J Polym Sci B Polym Phys

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Using in‐house synthesized poly(dodecamethylene terephthalate) (P12T) as a model, periodic extinction‐banded spherulites melt‐crystallized at high Tcs (100–115 °C) are expounded in terms of growth mechanism. The extinction‐banded spherulites wildly differing from the usual blue/orange double ring‐banded spherulites are composed of all flat‐on discrete single‐crystalline lamellae packed like roof shingles (or fish scales) along the circularly curved bands and the lamellae in the extinction bands are flat with a lozenge shape with no continuous twisting at all. For P12T films of more than 10 µm crystallized at Tc = 105–115 °C, no periodic bands were seen, and all spherulites were ringless, where periodic growth precipitation of crystals to extinction does not occur until impingement. Extinction bands in the P12T spherulites with the inter‐ring spacing steadily decrease with decreasing film thickness, because for thinner films (submicrons to 2 µm), draining or depletion of available molten species takes place more frequently, leading to bands of smaller inter‐ring spacing. The petal‐like extinction bands are discussed and analyzed in detail using 3D AFM imaging. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017, 55, 601–611

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Section: Introductionmentioning

confidence: 99%

Periodic extinction bands composed of all flat‐on lamellae in poly(dodecamethylene terephthalate) thin films crystallized at high temperatures

Lugito

Woo

Chang

2017

J Polym Sci B Polym Phys

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“…Therefore, we must use SEM to study the lamella twisting of PCL in the PCL/PLLA blends. In some papers the periodic change of the topographical structure of banded spherulites was investigated by SEM. The spherulites of the PCL/PLLA blends were etched by methylamine and then observed by SEM.…”

Section: Resultsmentioning

confidence: 99%

Disclosing the crystallization behavior and morphology of poly(ϵ‐caprolactone) within poly(ϵ‐caprolactone)/poly(l‐lactide) blends

Han

Liao

et al. 2018

Polymer International

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In this work, the effect of poly(l‐lactide) (PLLA) components on the crystallization behavior and morphology of poly(ϵ‐caprolactone) (PCL) within PCL/PLLA blends was investigated by polarized optical microscopy, DSC, SEM and AFM. Morphological results reveal that PCL forms banded spherulites in PCL/PLLA blends because the interaction between the two polymer components facilitates twisting of the PCL lamellae. Additionally, the average band spacing of PCL spherulites monotonically decreases with increasing PLLA content. With regard to the crystallization behaviors of PCL, the crystallization ability of PCL is depressed with increase of the PLLA content. However, it is interesting to observe that the growth rate of PCL spherulites is almost independent of the PLLA content while the overall isothermal crystallization rate of PCL within PCL/PLLA blends decreases first and then increases at a given crystallization temperature, indicating that the addition of PLLA components shows a weak effect on the growth rate of the PCL but mainly on the generation of nuclei. © 2018 Society of Chemical Industry

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“…It is informative to point out that ringed spherulites are not limited to high polymers; many small‐molecule compounds are able to crystallize into ringed spherulites. For example, phthalic acid (PA), upon crystallized in suitable conditions, has been proven to form similar ringed spherulites as many polymers …”

Section: Effect Of Chemical Structures Of Aryl Polyesters On Banding mentioning

confidence: 99%

Crystallization in arylate polyesters to periodically ringed assembly

Woo

Lee

2018

Polymer Crystallization

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Crystallization of arylate polymers are reviewed and analyzed for proposing interpretations for mechanisms of interior and surface‐relief lamellae packed into periodic banded patterns. Ring bands in polymers are typically characterized with dramatically different types that are distinguished by shapes, patterns, birefringence distribution, and height variation in ridge‐valley regions. Interior lamellae versus surface crystals that assemble into ring bands of different types are interpreted using novel mechanisms to be exemplified in this review. As the surface topology differs among different polymers with banding patterns, the inner structures may also differ correspondingly. In the past half a century, most investigations had approached the issues of periodic banding phenomenon only from top‐surface views on thin‐film specimens, which had encountered dilemma in incompleteness of searching for valid mechanisms. The surface relief and interior crystals in correlating with periodically optical birefringence in crystallized arylate polyesters are surveyed. Via thorough probes into the interior lamellar assembly that correlates with the optical birefringence in ringed spherulites of a series of arylate polyesters, objectives were to more fully expound plausible mechanisms, and aimed to identify common traits and features of banded polymer spherulites in homologous series of aryl‐polyesters.

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Analysis of crystal assembly in banded spherulites of phthalic acid upon solvent evaporation

Abstract: Differences are seen in the mechanism of lamellar assembly of two alternating banded regions (valley and ridge) of phthalic acid spherulites solvent-evaporation crystallized at either higher (80 °C) or ambient (28 °C) temperature.

Cited by 28 publications

References 34 publications

Periodic extinction bands composed of all flat‐on lamellae in poly(dodecamethylene terephthalate) thin films crystallized at high temperatures

Periodic extinction bands composed of all flat‐on lamellae in poly(dodecamethylene terephthalate) thin films crystallized at high temperatures

Disclosing the crystallization behavior and morphology of poly(ϵ‐caprolactone) within poly(ϵ‐caprolactone)/poly(l‐lactide) blends

Crystallization in arylate polyesters to periodically ringed assembly

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