Percolation-Driven Multiscale Roughening for Superhydrophobic Polymer Nanocomposite Coatings

A thermally equilibrated super-hydrophobic polymer nanocomposite coatings by forming highly hierarchal surfaces through percolation-driven surface segregation of the nanoparticles was reported. The polydimethylsiloxane (PDMS)-SiOx primary particle diameters were ~20nm, and primary aggregate lengths were ~100 nm, which were determined by using transmission electron microscopy (TEM). The suspensions were solution-cast into PTFE (Teflon) dishes for analysis of the bulk morphology using TEM. The nanocomposites and pure polystyrene (PS) coatings were annealed for 72 h at 160°C under argon. X-ray photoelectron spectroscopy (XPS) was used to quantify the atomic the atomic fractions of carbon, silicon, and oxygen within a sampling depth ~5-10 nm of the annealed polystyrene with narrow molecular weight distribution (PS-ND) nanocomposite surfaces and the effective surface volume fractions of PDMS-SiOx were approximated.