Reversed crystal growth of rhombohedral calcite in the presence of chitosan and gum arabic

Ritchie, A.W.; Watson, Michael I. T.; Turnbull, Robin; Zuo, Lijun; Telfer, Michael; Gano, Jerome E.; Self, Katherine; Greer, Heather F.; Zhou, Wuzong

doi:10.1039/c3ce41543k

Cited by 25 publications

(30 citation statements)

References 26 publications

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“…Indeed, we have observed such a phenomenon in many systems. For example, in zeolite analcime, an icositetrahedral single-crystal shell with 24 {211} facets forms, 22 in zeolite A a cubic shell develops, 36,37 ZnO forms a hexagonal prism shell, 38 and calcite forms a rhombohedral shell, 39 etc. In several of these systems, extended thermal treatment generated real single crystals through an extension of the crystallisation from the surface to the core, following the so-called reversed crystal growth route.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and Formation Mechanism of Textured MOF-5

Greer

Liu

Greenaway

et al. 2016

Crystal Growth & Design

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Textured and house-of-card structures develop on the surfaces of cubic MOF-5 crystals. The formation mechanism of these novel constructions are investigated based on characterisation of the intermediate specimens with different reaction time intervals using scanning and transmission electron microscopies. It is found that the growth of MOF-5 cubic crystals does not follow the classical route. MOF-5 nanocrystallites initially aggregate to form large polycrystalline cubes, followed by surface rearrangement of the nanocrystallites into a textured structure consisting of nanowires lying along the [100], [010], [110] and [110] zone axes, if the face of the cube is defined to be (001). Further crystal growth leads to a house-of-cards structure constructed by interpenetrated nanoplates with their shortest axis parallel to [110] and [110] axes. Evidence of a reversed crystal growth process is also observed. MOF-5 cubes with a single crystal-like appearance are achieved with extended reaction times despite their hidden three tier structure containing varying porosities hidden underneath.

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Section: Resultsmentioning

confidence: 99%

Synthesis and Formation Mechanism of Textured MOF-5

Greer

Liu

Greenaway

et al. 2016

Crystal Growth & Design

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“…As a comparative study for our travertine calcite, synthetic calcite was grown in chitosan gel [18]. Details on the synthetic method are outlined in the Supplementary Materials.…”

Section: Synthetic Calcite Grown In the Presence Of Chitosanmentioning

confidence: 99%

“…In the present work, high resolution SEM has been combined with high resolution transmission electron microscopy (HRTEM) in order to reveal the microstructure of natural travertine at atomic resolution. Finally, we report a comparative study of the structure and formation mechanisms of natural travertine with those obtained from previously reported biomimetic calcite prepared in the presence of chitosan [18].…”

Section: Introductionmentioning

confidence: 99%

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Reversed Crystal Growth of Calcite in Naturally Occurring Travertine Crust

2017

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Abstract:A microstructural investigation by electron microscopy on a travertine specimen collected from Munigou National Park, Sichuan Province, China revealed evidence of a non-classical reversed crystal growth route previously only discovered in synthetic materials. Examination of the travertine specimen suggests that the presence of organic matter initiates the oriented aggregation of calcite nanocrystallites. Surface re-crystallisation of the aggregates leads to a single crystalline rhombohedral shell with a polycrystalline core. This core-shell structure carries a strong resemblance to synthetic calcite prepared in the presence of chitosan, where the growth of calcite was found to follow the so-called reversed crystal growth process. It is proposed that the similar roles of biomolecules in naturally occurring travertine and chitosan in the synthetic system are based on their isoelectric points and the polymerizable property of long chain chemical structures. This study is important so that the structural similarities between naturally occurring biominerals and biomimetic materials can be further understood.

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“…Copper [37]; and some of the noble metals nano particle are prepared in the presence gum arabic [38] [39]. In addition, gum arabic is used in preparation of calcite [40], and magnetic nanoparticles [41].…”

Section: Introductionmentioning

confidence: 99%

Formation and Stabilization of Vaterite Calcium Carbonate by Using Natural Polysaccharide

Saraya¹,

Rokbaa²

2017

ANP

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This paper aimed to study the effects of natural polysaccharide (gum arabic, GA) on the formation of vaterite calcium carbonate and its stability in aqueous solution. Gum arabic is a macromolecule that has a high molecular weight and is amphoteric in character. A 0, 2.5, 5 or 10 ml of GA solution (30%) was added to the calcium chloride solution with various initial concentrations to prepare the vaterite calcium carbonate. The calcium carbonate particles were characterized using FTIR, XRD, SEM, TEM and DSC-TG as well as calculation of phase contents. The results of XRD and FTIR analysis were showing that the presence of GA during the precipitation changes the behavior of calcium carbonate to form vaterite until at lower dose used. In addition, the molar content of vaterite increased at the expense of content of calcite with increasing the GA dose. There are slightly improvements in the vaterite content by increasing the initial concentration. The formed vaterite calcium carbonates composed of aggregates as broccoli-like or spherical shape and with particle size 1.6 -2.5 µm in diameter. TEM images showed that these aggregates composed of the sub spherical unit with diameter 15 -30 nm. The thermal behavior of prepared vaterite was conformed the mineral composition of these phases. The prepared calcium carbonate, which is formed in the presence of different doses of gum, has a stability in the aqueous solutions at different temperatures, as the analyzes indicated that a very small percentage of the vaterite were converted to calcite. The gum arabic prevented or depressed the transformation of vaterite to calcite through capped the surface of particles, i.e. it is more effective in stabilizing the vaterite phase with increasing in initial concentration and time.

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Reversed crystal growth of rhombohedral calcite in the presence of chitosan and gum arabic

Cited by 25 publications

References 26 publications

Synthesis and Formation Mechanism of Textured MOF-5

Synthesis and Formation Mechanism of Textured MOF-5

Reversed Crystal Growth of Calcite in Naturally Occurring Travertine Crust

Formation and Stabilization of Vaterite Calcium Carbonate by Using Natural Polysaccharide

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