Fabrication of highly ordered nanoscale poly (lactic acid) surface based on self-assembled silica microspheres

A simple process was developed to fabricate poly (lactic acid) (PLA) film possessing a highly ordered nanoscale surface. For the first step, an array of silica microspheres was prepared by self-assembly on a completely hydrophilic silicon wafer. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) images showed that a highly ordered array was formed, and then this array was used as the template for fabricating polymer film with highly ordered nanoscale surface. Next, a PLA solution was spin coated on the template. After solidifying, silica microspheres were embedded in the thin layer of PLA, maintaining their highly organized structures. Finally, silica microspheres were etched away by hydrofluoric acid, and only the PLA film with a close-packed hexagonally pattern structure was left on the silicon wafer substrate. (C) 2011 Elsevier B.V. All rights reserved.