Fabrication of porous titania (brookite) microparticles with complex morphology by sol-gel replication of pollen grains

Chemistry of Materials

Volumn 18, Issue 3, 2006, Pages 598-600

  Hall, Simon R ^a   Swinerd, Victoria M ^a   Newby, Francisco N ^a   Collins, Andrew M ^a   Mann, Stephen ^a  

^a UNIVERSITY OF BRISTOL   (United Kingdom)

Author keywords

[No Author keywords available]

Indexed keywords

ETHANOL; IMAGE PROCESSING; MORPHOLOGY; SOL-GELS; WATER;

POLLEN GRAINS; TITANIUM ISOPROPOPXIDE (TIP);

TITANIUM COMPOUNDS;

EID: 32944459112     PISSN: 08974756     EISSN: None     Source Type: Journal    
DOI: 10.1021/cm0524087     Document Type: Article

References (15)

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11. Dandelion (Taraxacum) pollen was purchased from http://www.pollen-online.com. In a typical preparation, 0.01 g of dry Taraxacum pollen powder was added to 1 mL of a 50 wt % aqueous solution of ethanol (Merck; grade, absolute extra pure) in a 1.5 mL Eppendorf centrifuge tube, sonicated for 15 min followed by centrifugation at 13 200 rpm for 5 min and removal of the supernatant. A total of 1.5 mL of water (Milli-Q, 18.2 MΩ) was added to the pollen pellet, and the mixture was sonicated for 15 min prior to agitation overnight at 1000 rpm. The sample was then centrifuged at 13 200 rpm for 5 min, and the supernatant was removed leaving damp grains which directed the hydrolysis.
12. 15 A wide range of conditions were investigated; optimum conditions for producing high fidelity titania replicas are described as follows. A total of 1 mL of 100 μM TIP (97% in propanol, Aldrich, used as supplied) in 2-propanol was added to pelleted pollen grains prepared as as already described," and the sample was left for 15 min prior to centrifugation at 13 200 rpm for 5 min followed by removal of the supernatant and drying under vacuum. In some samples the sol was added above the solid; that is, the sol was allowed to percolate through the solid. In others the solid was added on top of the sol. Percolation was found to be the easiest approach. The pollen template was subsequently removed by calcination at 500°C for 3 h to produce titania replicas. Samples for SEM were prepared by mounting replicated grains on gummed carbon pads adhered to aluminum stubs with a diameter of 10 mm. Samples were also coated with a 15-nm-thick platinum film. Titania replicas were investigated by TEM using samples sonicated in ethanol prior to air drying these dispersions onto carbon-coated grids.
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14. -1) at room temperature. UV light was used to catalyze the reaction. Decomposition of methyl blue with time was monitored by UV-visible spectroscopy.
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