  We report the development of magnetic nanocomposite sheets with
superhydrophobic and superoleophilic surfaces generated by laser ablation.
Polydimethylsiloxane elastomer freestanding films, loaded homogeneously with 2%
wt. carbon coated iron nanoparticles, were ablated by UV (248 nm), nanosecond
laser pulses. The laser irradiation induces chemical and structural changes
(both in micro-and nano-scale) to the surfaces of the nanocomposites rendering
them superhydrophobic. The use of nanoparticles increases the UV light
absorption eficiency of the nanocomposite samples, and thus facilitates the
ablation process, since the number of pulses and the laser fluence required are
greatly reduced compared to the bare polymer. Additionally the magnetic
nanoparticles enhance significantly the super-hydrophobic and oleophilic
properties of the PDMS sheets, and provide to PDMS magnetic properties making
possible its actuation by a weak external magnetic field. These nanocomposite
elastomers can be considered for applications requiring magnetic MEMS for the
controlled separation of liquids.
