Fabrication of honeycomb film of an amphiphilic copolymer at the air-water interface

We report a new fabrication method of a thin polymer film with regular array of micropores (honeycomb film). A honeycomb film was fabricated by depositing a dilute solution of an amphiphilic polymer on water surface. The honeycomb film transferred onto a solid substrate was characterized by atomic force microscopy. By this fabrication method, it was possible to control film area, pore diameter, and film thickness. The pore size depended upon the evaporation time of the polymer solution spread on water surface. The thickness of a honeycomb film was controlled by spreading area of the polymer solution. The spreading behavior was influenced by the water temperature. The film area was proportional to the volume of spread polymer solution and controlled by changing the sub-phase temperature, too. When the polymer solution was simply cast on a solid substrate, a thin polymer layer remained in the bottom of the honeycomb pores. On the other hand, the honeycomb film fabricated on water surface has no bottom layer in its pores. A self-standing honeycomb mesh is formed by the "on-water spreading" method.