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Magill, J. H.

doi:10.1023/a:1017974016928

Cited by 165 publications

(147 citation statements)

References 43 publications

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“…influence spherulitic growth morphology. Multistage heat treatments on polymeric substances have demonstrated that that both the local growth morphology and growth rate depend on the temperature, but are independent of previous thermal history [1,10,62]. For example, cycling between two temperatures reversibly switches between faceted and spherulitic growth morphologies both in experiment [1,10] and simulation [ Figs.…”

Section: Multi-step Heat Treatmentsmentioning

confidence: 99%

Growth and form of spherulites

et al. 2005

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Many structural materials (metal alloys, polymers, minerals, etc.) are formed by quenching liquids into crystalline solids. This highly non-equilibrium process often leads to polycrystalline growth patterns that are broadly termed 'spherulites' because of their large-scale average spherical shape. Despite the prevalence and practical importance of spherulite formation, only rather qualitative concepts of this phenomenon exist. The present work explains the growth and form of these fundamental condensed matter structures on the basis of a unified field theoretic approach. Our phase field model is the first to incorporate the essential ingredients for this type crystal growth: anisotropies in both the surface energy and interface mobilities that are responsible for needle-like growth, trapping of local orientational order due to either static heterogeneities (impurities) or dynamic heterogeneities in highly supercooled liquids, and a preferred relative grain orientation induced by a misorientation-dependent grain boundary energy. Our calculations indicate that the diversity of spherulite growth forms arises from a competition between the ordering effect of discrete local crystallographic symmetries and the randomization of the local crystallographic orientation that accompanies crystal grain nucleation at the growth front (growth front nucleation or GFN). The large-scale isotropy of spherulitic growth arises from the predominance of GFN.

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Section: Multi-step Heat Treatmentsmentioning

confidence: 99%

Growth and form of spherulites

et al. 2005

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“…It also is a commonly observed phenomenon associated with crystallization in many other types of systems including metals (2). In addition, in the biphasic region of lyotropic liquid crystalline polymers, when the isotropic and anisotropic phases coexist, the anisotropic phase often forms spherulitic drops within an isotropic matrix (3).…”

mentioning

confidence: 99%

“…S pherulite formation is a very common form of self-assembly observed during polymer crystallization (1,2), particularly from synthetic polymer melts. It also is a commonly observed phenomenon associated with crystallization in many other types of systems including metals (2).…”

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confidence: 99%

The formation of spherulites by amyloid fibrils of bovine insulin

Krebs

MacPhee

Miller

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

235

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Bovine insulin has long been known to self-assemble in vitro into amyloid fibrils. We have observed a further higher-order selfassociation of the protein into spherical structures, with diameters typically around 50 m but ranging from 10 to 150 m. In a polarizing light microscope, these structures exhibit a ''Maltesecross'' extinction pattern typical of spherulites. Spherical structures of a similar size distribution can be observed in the environmental scanning electron microscope, which also reveals the presence of significant amounts of water in the structures. The spherulites contain a large quantity of well defined amyloid fibrils, suggesting that they are formed at least in part as a consequence of the self-assembly of preformed fibrils. Similar structures also have been observed in the tissues of patients suffering from amyloid disorders. The ability of amyloid fibrils to form such higher-order assemblies supports the hypothesis that they represent a generic form of polypeptide structure with properties that are analogous to those of classical synthetic polymers.

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“…Damage is a direct result of specific interactions between semi-crystalline patterns and solvent with a preferential interaction (but not exclusive) in the amorphous phase Devisme et al, 2007). However, such an interpretation cannot be extrapolated to low crystallization temperatures encountered in polymer processing, i.e., to high cooling rates (Magill, 1961(Magill, , 1962(Magill, , 2001Haudin et al, 2008;Boyer et al, 2011b). In front of the necessity for obtaining crystallization data at high cooling rates, different technical solutions are proposed.…”

Section: Damage Of Polymer Structure In On-duty Conditionsmentioning

confidence: 99%