Master Mold Fabrication: The Al master was fabricated by computer numerical control CNC machining with a 0.5 mm, 15° end mill, in a custom made 70k rpm tool. The Al template was further processed by a timed (1.5 h) chemical wet etch in Al etchant at 50° (Al etchant type A, 80% phosphoric acid, 5%, nitric acid, 5% acetic acid, and 10% distilled water).