Thermally stable and solvent resistant mesoporous honeycomb films from a crosslinkable polymer

The preparation of mesoporous honeycomb films, also known as breath figure arrays (BFAs), from poly(styrene-co-maleic anhydride) is reported. Films containing regular arrays of micrometer-sized air-holes were prepared by evaporation of a chloroform solution of a mixture of the above polymer including 10% of an amphiphilic polyion complex under high humidity that leads to the formation of a hexagonally packed monolayer of water droplets in the polymer film. The porous films were characterized by optical and scanning electron microscopy. Crosslinking was achieved by immersion in an ethanol solution of an a, W alkyldiamine and the chemical reaction was monitored by infrared spectroscopy. The non-crosslinked films are hydrophobic with a water contact angle of more than 90 degrees, whereas the crosslinked films became hydrophilic, so that a water drop penetrated into the films. After crosslinking, the honeycomb structure was stable to up to 350 degrees C, an increase of more than 150 K as compared to the non-crosslinked films.