Optimization of anodic porous alumina fabricated from commercial aluminum food foils: A statistical approach

摘要

Anodic porous alumina is a known material based on an old industry, yet with emerging\udapplications in nanoscience and nanotechnology. This is promising, but the nanostructured\udalumina should be fabricated from inexpensive raw material. We fabricated porous alumina from\udcommercial aluminum food plate in 0.4 M aqueous phosphoric acid, aiming to design an effective\udmanufacturing protocol for the material used as nanoporous filler in dental restorative composites,\udan application demonstrated previously by our group. We identified the critical input parameters\udof anodization voltage, bath temperature and anodization time, and the main output parameters of\udpore diameter, pore spacing and oxide thickness. Scanning electron microscopy and grain analysis\udallowed us to assess the nanostructured material, and the statistical design of experiments was\udused to optimize its fabrication. We analyzed a preliminary dataset, designed a second dataset\udaimed at clarifying the correlations between input and output parameters, and ran a confirmation\uddataset. Anodization conditions close to 125 V, 20°C, and 7 h were identified as the best for\udobtaining, in the shortest possible time, pore diameters and spacing of 100–150 nm and 150–275 nm\udrespectively, and thickness of 6–8 μm, which are desirable for the selected application according to\udpreviously published results. Our analysis confirmed the linear dependence of pore size on\udanodization voltage and of thickness on anodization time. The importance of proper control on the\udexperiment was highlighted, since batch effects emerge when the experimental conditions are not\udexactly reproduced.