title: Micropatterned surfaces through moisture-induced phase-separation of polystyrene-clay nanocomposite particles.
abstract: We report micropatterned polystyrene-clay nanocomposite (PCN) surfaces with concavities by moisture-induced phase separation of PCN particles. Micropatterned film with concavity size of 800 nm to 1.3 microm and a high number density of 2 x 10(8) features/cm(2) was obtained by drop-casting PCN solution (20 mg/mL PCN/THF) under ambient relative humidity of 70-80%. It is proposed that water droplets were channeled through the hydrophilic interfaces between the PCN particles, and the two-dimensional array of concavities was formed by spontaneous phase separation due to the presence of rigid clay platelets. The concavity size and number density can be tuned by varying the solvent for PCN. Micropatterned film with concavity size in the range of 650 nm to 1.1 microm with a number density of 5 x 10(7) features/cm(2) was obtained using chloroform as solvent, whereas a concavity size of 150-740 nm and number density of 10(8) features/cm(2) were obtained using carbon disulfide.
authors.affiliation: Materials and Minerals Division, National Institute for Interdisciplinary Science and Technology, Council of Scientific and Industrial Research, Thiruvananthapuram 695019, India.
authors.forename: Bindu P
authors.initials: BP
authors.lastname: Nair
authors.forename: Chorappan
authors.initials: C
authors.lastname: Pavithran
mesh_terms: D000538:Aluminum Silicates / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D053761:Nanocomposites / Q000737:chemistry* / Q000648:ultrastructure; D036103:Nanotechnology; D011137:Polystyrenes / Q000737:chemistry*
chemical_list: D000538:Aluminum Silicates; D011137:Polystyrenes