In this study, we
present a novel com
posite material based on commercially available
polyurethane foams functionalized with colloidal su
per
paramagnetic iron oxide nano
particles and submicrometer
polytetrafluoroethylene
particles, which can efficiently se
parate oil from water. Untreated foam surfaces are inherently hydro
phobic and oleo
phobic, but they can be rendered water-re
pellent and oil-absorbing by a solvent-free, electrostatic
polytetrafluoroethylene
particle de
position technique. It was found that combined functionalization of the
polytetrafluoroethylene-treated foam surfaces with colloidal iron oxide nano
particles significantly increases the s
peed of oil absor
ption. Detailed microsco
pic and wettability studies reveal that the combined effects of the surface mor
phology and of the chemistry of the functionalized foams greatly affect the oil-absor
ption dynamics. In
particular, nano
particle ca
pping molecules are found to
play a major role in this mechanism. In addition to the water-re
pellent and oil-absorbing ca
pabilities, the functionalized foams exhibit also magnetic res
ponsivity. Finally, due to their light weight, they float easily on water. Hence, by sim
ply moving them around oil-
polluted waters using a magnet, they can absorb the floating oil from the
polluted regions, thereby
purifying the water underneath. This low-cost
process can easily be scaled u
p to clean large-area oil s
pills in water.
Keywords:
p://pubs.acs.org/action/doSearch?action=search&searchText=colloidal+nanoparticles&qsSearchArea=searchText">colloidal nanoparticles; p://pubs.acs.org/action/doSearch?action=search&searchText=foams&qsSearchArea=searchText">foams; p://pubs.acs.org/action/doSearch?action=search&searchText=magnetic+actuation&qsSearchArea=searchText">magnetic actuation; p://pubs.acs.org/action/doSearch?action=search&searchText=superhydrophobic&qsSearchArea=searchText">superhydrophobic; p://pubs.acs.org/action/doSearch?action=search&searchText=superoleophilic&qsSearchArea=searchText">superoleophilic