An electrospray unit was built in order to deposit preformed metal nanoparticles on various substrates. Furthermore, due to treatment of the deposited particles with an oxygen plasma, the particles were stripped of their ligands and strongly fixed to the surface. These treated surfaces can be expected to exhibit properties that differ characteristically from bare surfaces. Depending on the substrate itself, but even more on the size the density of the deposited nanoparticles, the contact angles and thereby the wettability could be varied drastically. Gold nanoparticles of 17 nm diameter on titanium decreased the contact angle from 82° to 34°, whereas 6-8 nm palladium particles increased the wettability to such a degree that a contact angle could not be determined. In contrast to the electrospray technique, a pneumatically operated device was constructed, allowing simultaneous spraying and plasma pyrolysis.
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