Hierarchically ordered α-zirconium phosphate platelets in aqueous phase with empty liquid
| Autor: | Horst Hintze-Bruening, Dirk Schmelter, Sadaf Imanian, Xi Lin |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Materials science
Intercalation (chemistry) chemistry.chemical_element lcsh:Medicine 02 engineering and technology 010402 general chemistry 01 natural sciences Article Colloid chemistry.chemical_compound Liquid crystal lcsh:Science chemistry.chemical_classification Zirconium Nanoscale materials Multidisciplinary Small-angle X-ray scattering Soft materials lcsh:R Polymer 021001 nanoscience & nanotechnology Exfoliation joint 0104 chemical sciences chemistry Chemical engineering Zirconium phosphate lcsh:Q 0210 nano-technology |
| Zdroj: | 'Scientific Reports ', vol: 9, pages: 16389-1-16389-15 (2019) Scientific Reports, Vol 9, Iss 1, Pp 1-15 (2019) Scientific Reports |
| ISSN: | 2045-2322 |
| Popis: | Platelets of α-zirconium phosphate (α-ZrP) obtained from the reflux method in H3PO4 are successfully exfoliated into water via the intercalation of alkanol amines. With volume fractions greater than 0.02 they are stacked into tactoids of few layers with a repeat distance in the order of 10 nm. The tactoids align into nematic liquid crystalline phases with irregularly wide interstices of empty liquid. Colloidal processing involves the freeze-drying of such anisotropic fluids and the dispersion of the restacked tacoids into aqueous dispersions of colloidal polymer particles of largely varying size which occupy the otherwise empty liquid between the α-ZrP tactoids and induce piling of the tactoids into columns. Real-time SAXS on drying films and TEM of the obtained coatings demonstrate that the stacked α-ZrP platelets and the polymer particles comprising liquid dry separately without polymer intercalation, while the morphology of the obtained composites can be tuned primarily by the size of the polymer colloids. Concomitant α-ZrP hydrolysis in the exfoliation step is scrutinized as a function of amine basicity and temperature. The role of zirconium based hydrolysis products in the hierarchical α-ZrP assembly is indirectly though consistently confirmed by opposing impacts of ultra-filtration and added oxoanions on the platelets’ spacing, smoothness and aggregation. HAADF-TEM imaging of scattered, singular platelets and XRD peak analysis of the pristine solid shed light on the α-ZrP synthesis. Coexisting flakes and lacunae, both similar in size to the intra-layer crystal domains, suggest the stitching of proto-α-ZrP flakes into extended layers in accordance with our observations on the aging behaviour of α-ZrP dispersions as well as with literature data on related systems. |
| Databáze: | OpenAIRE |
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