were repeatedly gently rubbed in predetermined directions using pdms poly dimethysiloxane plates 4 0 u00d7 4 0 u00d7 0 5 cm 3 the rubbing was performed for about one minute until a substrate surface got slight rainbow colors by light reflection in case of using the patterned pr coated silicones wafers the powdered silica beads were placed on the patterned pr coated wafers and then repeatedly gently rubbed in a predetermined direction using a pdms plate in the presence of water here water was used as a lubricant to prevent damage to the patterned pr after the rubbing the silica bead coated glass plates or silicone wafers were subjected to slight pressing using clean pdms plates or to gentle brushing in order to remove randomly physically adsorbed undesired silica beads thus resulting in formation of more tightly regularly bound monolayer arrays of the silica beads for layer by layer stacking the above formed monolayer arrays were calcined at 550 u00b0 c for one hour a droplet of a solution of pei 0 5 in ethanol was spin coated on the calcined silica bead arrays silica beads were further placed on the pei coated silica bead arrays and then were rubbed as described above to form two layered silica bead arrays.