Browsing by Subject "Nanoprinting"

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Open Access
Capillary origami as a new method for printing nanoparticles on 3D surfaces
(Chemical and Biological Microsystems Society, 2016) Özkazanç, Gökçe; Erdem, Emine Yegan
We introduce capillary origami as a new method to print nanoparticles on curved, three dimensional polymer surfaces. When a liquid droplet containing nanoparticles is placed on a thin PDMS (polydimethylsiloxane) membrane, as the droplet evaporates, it folds the surface and leaves nanoparticles on it. We produced curved surfaces covered with a layer of magnetic iron-oxide (Fe3O4) nanoparticles with this method. These coated surfaces can be moved in a magnetic field.
Open Access
Directed assembly of charged nanoparticles by using electrostatic forces in a fluidic medium
(2019-02) Sopubekova, Eliza
Deposition of nanoparticles in a controlled manner is suitable for the application of unique properties of nanoparticles in designing novel electronic devices. Printing different types of nanoparticles on the same surface generates multifunctional surfaces and opens up possibilities to elaborate future devices. Electrostatic forces can potentially be utilized to manipulate different types of materials such as magnetic, insulating, conducting, semiconducting, organic and inorganic materials. Moreover, chemistry of materials and the surface is not altered. Herein, we applied these forces to direct and position charged nanoparticles on desired areas of the surface from nonpolar and aqueous dispersions. Assemblies of particles are obtained on both nonconductive surface with charged patterns and on metallic nano- and microstructured electrodes. Arrays of gold electrodes of sizes from 500 nm to 50 μm were prepared by using the conventional fabrication techniques such as photolithography, electron beam lithography, thermal evaporation and lift off. Charge patterns are formed on 100 nm PMMA surface which is coated on the electrodes to provide electrical contact. An external voltage was applied and substrate was immersed into desired aqueous negatively charged colloidal gold dispersion to direct nanoparticles on aforementioned charge patterns. The next step was to attract two different charged nanoparticles towards different locations on the same substrate by means of electrophoretic deposition. Assemblies formed from positively charged silver nanoparticles and negatively charged fluorescent latex and silica nanoparticles are demonstrated. Last but not least, composite structures were obtained with similar techniques in order to increase the functionality of the structured surface. To achieve this goal, different types of nanoparticles were coated on top of each other without changing the location of electrodes. The shape of these composite structures is controlled by the electrode geometry.