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Taylor, John D. - One of the best experts on this subject based on the ideXlab platform.
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Figure 6 from: Glover EA, Taylor JD (2016) Pleurolucina from the western Atlantic and eastern Pacific Oceans: a new intertidal species from Curaçao with unusual shell microstructure (Mollusca, Bivalvia, Lucinidae). ZooKeys 620: 1-19. https://doi.org/
2016Co-Authors: Glover, Emily A., Taylor, John D.Abstract:Figure 6 - Shell microstructure of other species Pleurolucina hendersoni, Pleurolucina undata, Lucina pensylvanica and Cardiolucina quadrata. A Pleurolucina hendersoni Guadeloupe, fractured section with prominent calcified conchiolin layer, periostracum at base. Scale bar = 20 µm B Pleurolucina hendersoni, detail of conchiolin layer with lines of calcareous Spherulites. Scale bar = 20 µm C Pleurolucina undata Baja California, fractured section with thin conchiolin layer Scale bar = 200 µm D Pleurolucina undata, detail of conchiolin layer with Spherulites. Scale bar = 20 µm E Pleurolucina undata, single Spherulites embedded in conchiolin. Scale bar = 3 µm F Lucina pensylvanica Florida Keys, calcified conchiolin layer. Scale bar = 20 µm G Lucina pensylvanica, single spherulite. Scale bar = 2 µm H Lucina pensylvanica, section of periostracum with calcareous granules. Shell interior to top. Scale bar = 20 µm I Cardiolucina quadrata Philippines, fractured section with conchiolin layer. Scale bar = 200 µm J Cardiolucina quadrata detail of conchiolin layer with calcareous aggregates. Scale bar = 50 µm K Cardiolucina quadrata detail of calcareous aggregate. Scale bar = 10 µm
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Figure 4 from: Glover EA, Taylor JD (2016) Pleurolucina from the western Atlantic and eastern Pacific Oceans: a new intertidal species from Curaçao with unusual shell microstructure (Mollusca, Bivalvia, Lucinidae). ZooKeys 620: 1-19. https://doi.org/
2016Co-Authors: Glover, Emily A., Taylor, John D.Abstract:Figure 4 - Shell microstructure of Pleurolucina harperae. A Fractured section of shell margin showing major notch growth halt and conchiolin layer. Scale bar = 400 µm B Fractured section showing succession of shell layers. Shell exterior at top. Scale bar = 100 µm C Conchiolin layer with regular bands of Spherulites. Scale bar = 40 µm D Individual spherulite. Scale bar = 2 µm E Adjacent Spherulites embedded in conchiolin with narrow channels between layers. Scale bar = 5 µm F Single Spherulites with channels below and above. Scale bar = 5 µm. cl crossed lamellar layer co conchiolin layer cp composite prismatic layer ip irregular prismatic layer p periostracum sp spherulitic prismatic layer
Mariano Campoyquiles - One of the best experts on this subject based on the ideXlab platform.
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one step macroscopic alignment of conjugated polymer systems by epitaxial crystallization during spin coating
Advanced Functional Materials, 2013Co-Authors: Christian Muller, Mahdieh Aghamohammadi, Scott Himmelberger, Prashant Sonar, M Garriga, Alberto Salleo, Mariano CampoyquilesAbstract:The one-step preparation of highly anisotropic polymer semiconductor thin films directly from solution is demonstrated. The conjugated polymer poly(3-hexylthiophene) (P3HT) as well as P3HT:fullerene bulk–heterojunction blends can be spin-coated from a mixture of the crystallizable solvent 1,3,5-trichlorobenzene (TCB) and a second carrier solvent such as chlorobenzene. Solidification is initiated by growth of macroscopic TCB Spherulites followed by epitaxial crystallization of P3HT on TCB crystals. Subsequent sublimation of TCB leaves behind a replica of the original TCB Spherulites. Thus, highly ordered thin films are obtained, which feature square-centimeter-sized domains that are composed of one spherulite-like structure each. A combination of optical microscopy and polarized photoluminescence spectroscopy reveals radial alignment of the polymer backbone in case of P3HT, whereas P3HT:fullerene blends display a tangential orientation with respect to the center of spherulite-like structures. Moreover, grazing-incidence wide-angle X-ray scattering reveals an increased relative degree of crystallinity and predominantly flat-on conformation of P3HT crystallites in the blend. The use of other processing methods such as dip-coating is also feasible and offers uniaxial orientation of the macromolecule. Finally, the applicability of this method to a variety of other semi-crystalline conjugated polymer systems is established. Those include other poly(3-alkylthiophene)s, two polyfluorenes, the low band-gap polymer PCPDTBT, a diketopyrrolopyrrole (DPP) small molecule as well as a number of polymer:fullerene and polymer:polymer blends.
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one step macroscopic alignment of conjugated polymer systems by epitaxial crystallization during spin coating
Science & Engineering Faculty, 2013Co-Authors: Christian Muller, Mahdieh Aghamohammadi, Scott Himmelberger, Prashant Sonar, M Garriga, Alberto Salleo, Mariano CampoyquilesAbstract:The one-step preparation of highly anisotropic polymer semiconductor thin films directly from solution is demonstrated. The conjugated polymer poly(3-hexylthiophene) (P3HT) as well as P3HT:fullerene bulk-heterojunction blends can be spin-coated from a mixture of the crystallizable solvent 1,3,5-trichlorobenzene (TCB) and a second carrier solvent such as chlorobenzene. Solidification is initiated by growth of macroscopic TCB Spherulites followed by epitaxial crystallization of P3HT on TCB crystals. Subsequent sublimation of TCB leaves behind a replica of the original TCB Spherulites. Thus, highly ordered thin films are obtained, which feature square-centimeter-sized domains that are composed of one spherulite-like structure each. A combination of optical microscopy and polarized photoluminescence spectroscopy reveals radial alignment of the polymer backbone in case of P3HT, whereas P3HT:fullerene blends display a tangential orientation with respect to the center of spherulite-like structures. Moreover, grazing-incidence wide-angle X-ray scattering reveals an increased relative degree of crystallinity and predominantly flat-on conformation of P3HT crystallites in the blend. The use of other processing methods such as dip-coating is also feasible and offers uniaxial orientation of the macromolecule. Finally, the applicability of this method to a variety of other semi-crystalline conjugated polymer systems is established. Those include other poly(3-alkylthiophene)s, two polyfluorenes, the low band-gap polymer PCPDTBT, a diketopyrrolopyrrole (DPP) small molecule as well as a number of polymer:fullerene and polymer:polymer blends. Macroscopic spherulite-like structures of the conjugated polymer poly(3-hexylthiophene) (P3HT) grow directly during spin-coating. This is achieved by processing P3HT or P3HT:fullerene bulk heterojunction blends from a mixture of the crystallizable solvent 1,3,5-trichlorobenzene and a second carrier solvent such as chlorobenzene. Epitaxial growth of the polymer on solidified solvent crystals gives rise to circular-symmetric, spherulite-like structures that feature a high degree of anisotropy.
Eamor M Woo - One of the best experts on this subject based on the ideXlab platform.
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multishell oblate spheroid growth in poly trimethylene terephthalate banded Spherulites
Macromolecules, 2017Co-Authors: Graecia Lugito, Eamor M WooAbstract:Unique interior dissection coupled with selective etching techniques for exposing the interiors of poly(trimethylene terephthalate) (PTT) banded Spherulites. Three banded PTT spherulite types are present, originating from different nuclei geometries and corresponding to different assemblies of interior lamellae, but all possess similar multishell spheroid layered structures, each with their layer thickness exactly equal to the optical interband spacing. Interior lamellae are alternatingly intersected with mutually perpendicular orientations and clear discontinuity, which evidently disagrees with the conventional models of continuous helical twisting for banding. Interior 3D lamellae assemblies also have been fittingly correlated with top-surface banding patterns.
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effects of amorphous poly vinyl acetate on crystalline morphology of poly 3 hydroxybutyric acid co 3 hydroxyvaleric acid
Colloid and Polymer Science, 2011Co-Authors: Ling Chang, Yinhsuan Chou, Eamor M WooAbstract:The amorphous and crystalline phase behavior, spherulite morphology, and interactions between amorphous poly(vinyl acetate) (PVAc) and poly(3-hydroxybutyric acid-co-3-hydroxyvaleric acid) (PHBV) were examined using differential scanning calorimetry, polarized-light optical and scanning electron, atomic-force microscopy (DSC, POM, SEM, AFM), and small-angle X-ray scattering (SAXS). The PHBV/PVAc blend was found to be miscible with an almost linear Tg-composition relationship, indicating perfect homogeneity. Interaction parameter by melting point depression is a negative value of χ = −0.32, suggesting quite favorable interaction strength. With the intimate interaction between the amorphous PVAc and crystalline PHBV polymers, effects of PVAc on the spherulitic morphology of PHBV are quite significant. Owing to the higher Tg of PVAc (than that of PHBV), the spherulite growth rate of PHBV was depressed by increasing PVAc content in blends. Neat PHBV exhibits ring-banded Spherulites when crystallized at \( {T_{\rm{c}}} = {6}0\sim {11}0^\circ {\hbox{C}} \); however, with increasing PVAc content in the blends, the temperature range at which the PHBV/PVAc blends exhibit ring-banded Spherulites remains similar but the regularity increases, and the inter-ring spacing significantly decreases. In addition, the spherulite size and ring-band patterns therein are strongly dependent on Tmax (190 vs. 220 °C, respectively, for erasing prior nuclei), from which the blends were quenched to a Tc (60–110 °C) for crystallization. For PHBV/PVAc blends crystallized at the same Tc from different Tmax, higher Tmax tends to erase nuclei, leading to larger Spherulites. However, such larger Spherulites owing to higher Tmax are not necessarily packed with thicker lamellae.
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dual types of Spherulites in poly octamethylene terephthalate confined in thin film growth
Langmuir, 2008Co-Authors: Yufan Chen, Eamor M WooAbstract:Spherulite morphology and growth kinetics of poly(octamethylene terephthalate) (POT), cast on single-side glass or confined between two slides in thin-film forms, were characterized using polarized versus nonpolarized optical microscopy, scanning electron microscopy (SEM), and wide-angle X-ray (WAXD) analysis. POT can simultaneously display solely one type of spherulite or dual types of Spherulites (double-ring-banded and ringless ones), depending on T c or T max imposed. Fractions of these two types depend on T c when quenched from a fixed T max = 160 degrees C. At lower T c's, POT exhibits higher crystallization rates leading to higher fractions of ringless Spherulites; at higher T c's, POT exhibits lower crystallization rates leading to ring-banded Spherulites. At intermediate to high T c's where the growth kinetics of POT could be monitored, the ring-band type dominates and the fraction of ringless Spherulites is insignificantly small. Both ringless and ring-banded Spherulites can be seen in regime III ( T c = 70-110 degrees C), with fractions of ringless type of Spherulites decreasing with temperature. Thus, growth kinetics for POT was mainly focused on the regime of ring-banded Spherulites. In regime III, the ring-band pattern is more orderly concentric with smaller inter-ring spacing (1-2 mum) for lower T c's but intermediately larger spacing (3-5 mum) for higher T c's. The orderly lamellar orientation in the ring-bands in contrast with the inter-ring valley region is discussed. In regime II (115 degrees C and above), the ring-band pattern is first distorted to highly zigzag irregularity at higher T c's and then eventually disappears at extremely high T c, with the lamellar crystals eventually turning dendritic with no rings. Apparently, the types of Spherulites in polymers are more influenced by the growth rates as determined by T c and slightly less by T max, but not by the substrate surface nucleation.
Glover, Emily A. - One of the best experts on this subject based on the ideXlab platform.
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Figure 6 from: Glover EA, Taylor JD (2016) Pleurolucina from the western Atlantic and eastern Pacific Oceans: a new intertidal species from Curaçao with unusual shell microstructure (Mollusca, Bivalvia, Lucinidae). ZooKeys 620: 1-19. https://doi.org/
2016Co-Authors: Glover, Emily A., Taylor, John D.Abstract:Figure 6 - Shell microstructure of other species Pleurolucina hendersoni, Pleurolucina undata, Lucina pensylvanica and Cardiolucina quadrata. A Pleurolucina hendersoni Guadeloupe, fractured section with prominent calcified conchiolin layer, periostracum at base. Scale bar = 20 µm B Pleurolucina hendersoni, detail of conchiolin layer with lines of calcareous Spherulites. Scale bar = 20 µm C Pleurolucina undata Baja California, fractured section with thin conchiolin layer Scale bar = 200 µm D Pleurolucina undata, detail of conchiolin layer with Spherulites. Scale bar = 20 µm E Pleurolucina undata, single Spherulites embedded in conchiolin. Scale bar = 3 µm F Lucina pensylvanica Florida Keys, calcified conchiolin layer. Scale bar = 20 µm G Lucina pensylvanica, single spherulite. Scale bar = 2 µm H Lucina pensylvanica, section of periostracum with calcareous granules. Shell interior to top. Scale bar = 20 µm I Cardiolucina quadrata Philippines, fractured section with conchiolin layer. Scale bar = 200 µm J Cardiolucina quadrata detail of conchiolin layer with calcareous aggregates. Scale bar = 50 µm K Cardiolucina quadrata detail of calcareous aggregate. Scale bar = 10 µm
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Figure 4 from: Glover EA, Taylor JD (2016) Pleurolucina from the western Atlantic and eastern Pacific Oceans: a new intertidal species from Curaçao with unusual shell microstructure (Mollusca, Bivalvia, Lucinidae). ZooKeys 620: 1-19. https://doi.org/
2016Co-Authors: Glover, Emily A., Taylor, John D.Abstract:Figure 4 - Shell microstructure of Pleurolucina harperae. A Fractured section of shell margin showing major notch growth halt and conchiolin layer. Scale bar = 400 µm B Fractured section showing succession of shell layers. Shell exterior at top. Scale bar = 100 µm C Conchiolin layer with regular bands of Spherulites. Scale bar = 40 µm D Individual spherulite. Scale bar = 2 µm E Adjacent Spherulites embedded in conchiolin with narrow channels between layers. Scale bar = 5 µm F Single Spherulites with channels below and above. Scale bar = 5 µm. cl crossed lamellar layer co conchiolin layer cp composite prismatic layer ip irregular prismatic layer p periostracum sp spherulitic prismatic layer
Sébastien Roland - One of the best experts on this subject based on the ideXlab platform.
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Numerical study of the relationship between the spherulitic microstructure and isothermal crystallization kinetics. Part I. 2-D
Polymer, 2019Co-Authors: Fabrice Detrez, Sébastien RolandAbstract:In this paper, we proposed a numerical model to study the kinetic properties and the spherulite microstructure of a semi-crystalline polymer under isothermal crystallization, which further exhibits the potential in generating the 2D spherulitic structure according to the observations obtained by experimental techniques. Two characteristic parameters are introduced, namely, characteristic length Lc and characteristic time tc, which are dependent on the growth rate, G and the nucleation rate, I. In addition, two non-dimensional parameters are introduced to model the nucleation saturation: Ld/Lc and t⋆/tc, which is related to the thickness of nucleation exclusion zone Ld, and the effective nucleation time t⋆, respectively. In 2D modeling, the kinetics are confirmed by Avrami fitting, and the effects of the four characteristic parameters on the Avrami parameter n and the crystallization half-time t0.5 are presented. The regularity of how the spherulite density or the mean radius of Spherulites R change along with these parameters are also given, respectively. It shows that Lc is the prominent parameter for the size of the spherulite, and tc controls t0.5 as long as there is no nucleation saturation (Ld=0 and t⋆→∞). Besides, the existence of the nucleation saturation increases the mean radius of Spherulites, but decreases n from 3 to 2 in 2-D modeling. Finally, a relationship between crystallization kinetics and microstructures is provided, giving a new perspective to estimate the nucleation rate.
