Solid microscopic rings formed via wetting and subsequent dewetting
| Autor: | Olivia du Roure, Joe W. Tavacoli, Aidan T. Brown, Pierre Bauër, Julien Heuvingh |
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| Rok vydání: | 2016 |
| Předmět: |
Materials science
General Chemical Engineering Evaporation Nanotechnology 02 engineering and technology General Chemistry 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences Contact angle Colloid Meniscus Dewetting Wetting Composite material 0210 nano-technology Dispersion (chemistry) Superparamagnetism |
| Zdroj: | RSC Advances. 6:62624-62629 |
| ISSN: | 2046-2069 |
| Popis: | We report the spontaneous formation of rings when a colloidal dispersion, containing silica-coated iron-oxide particles and the liquids ethanol and ethoxylated trimethylolpropane triacrylate, is deposited within micron-sized PDMS wells. Just after filling, the interface between air and the dispersion is a meniscus dictated by the dispersion's contact angle on PDMS. Upon evaporation of ethanol the meniscus lowers and, if a critical volume is reached, a rupture process is initiated and the dispersion adopts a ring morphology. The final dispersion consists only of particles and ethoxylated trimethylolpropane triacrylate that can be reticulated to solidify the ring geometry. The colloidal particles within the dispersion are essential for the stability of the rings prior to the reticulation. Here, by using iron-oxide based colloidal particles we fabricated superparamagnetic rings, opening up new avenues for applications. The dimensions of the rings can be tuned by adjusting both the size of the PDMS wells and the amount of ethanol in the dispersion. In this manner it is possible to fabricate rings with annuli smaller than a micron – a scale below the lower limit of standard lithography. Calculations assuming an equilibrium contact angle of ethoxylated trimethylolpropane triacrylate on PDMS reproduce the experimental results strikingly well. |
| Databáze: | OpenAIRE |
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