Fast Fabrication of Localized Porous Alumina Patterns with 3D Printed Microdroplet Cell

Abstract

A multicapillary 3D printed solution flow type microdroplet cell (Sf-MDC) is proposed for high-throughput local anodizing. The optimally designed 3D printed Sf-MDC offers low resin consumption, shorter fabrication time and increased throughput. The Sf-MDC consists of three solution inlets separately connected with inner capillaries, a common solution outlet for removing the excess solution from outer capillaries and a two-electrode system with a common Pt counter electrode. Three major acidic electrolytes, i.e. 0.3 M H 2 SO 4 , 0.22 M (COOH) 2 and 0.1 M H 3 PO 4 are used for simultaneous local anodizing. The simultaneously anodized lines exhibit uniform length, width and porous structure for each anodizing solution. Relationship between anodized line width, diameter of capillaries, inlet flow rate and vacuum pressure is studied. By varying the concentration of (COOH) 2 electrolyte inside each inner capillary, three porous alumina membranes with different oxide thicknesses and pore diameters are simultaneously fabricated. The microcell showed good reproducibility and can be applied for fast fabrication of porous alumina filters and electronic components.