Formation and properties of isoporous films composed of polymer semiconductors

Ordered hexagonal arrays of isoporous films prepared from poly(9,9'-dihexylfluorene) and polystyrene grafted silica nanoparticles (Si-graft-PS) are presented. These close packed arrays were formed in areas of many square millimeters. The pore size varied from 2.9 - 8.5 μm, depending on the concentration of Si-graft-PS and the processing conditions. Solid state photoluminescence resulted in a significant red shift of up to 30 nm in these films compared to conventional processing techniques. These differences are attributed to induced aggregation of the polymers caused by polymer-solvent interactions. Interfacial properties were investigated, and it was found that hydrophobic surfaces (contact angles of up to 129°) were prepared because of high surface roughness. These ordered porous polymer films may find use in microelectronic and bio- and/or chemical sensor applications.