phosphoric acid

ChEBI · EMBL-EBI ↗ · Källdatum saknas · Källans villkor

A phosphorus oxoacid that consists of one oxo and three hydroxy groups joined covalently to a central phosphorus atom.

ChenChun-Ko; ChenSheng-Hui · Multi-electrolyte-step anodic aluminum oxide method for the fabrication of self-organized nanochannel arrays ↗ · Feb 14, 2012 · Källans villkor

The anodization conditions of the multi-electrolyte-step AAO method were as follows: a 1-wt.% phosphoric acid solution was used as the electrolyte, and the applied voltage was 120 V for a few minutes. Then, the phosphoric acid solution was replaced by an oxalic acid solution as the electrolyte, and an applied voltage of 50 V for 30 min was used. Figure 4 shows a flowchart of the multi-electrolyte-step AAO method.

ChenChun-Ko; ChenSheng-Hui · Multi-electrolyte-step anodic aluminum oxide method for the fabrication of self-organized nanochannel arrays ↗ · Feb 14, 2012 · Källans villkor

Finally, the multi-electrolyte-step AAO method is also analyzed and compared with the multi-step AAO method. A flowchart of the fabrication process is shown in Figure 4. At the beginning of the process, the self-organized nanochannels grew with a large period, 202 nm. A phosphoric acid electrolyte was used with an applied voltage of 120 V for a few minutes. After anodization, the porous oxide films were removed by being submerged in a 0.5-M NaOH solution for 8 min to achieve the nanobowl structures. Then, the nanochannel arrays grew again from the center of the nanobowl structure in the oxalic acid solution with 50 V of applied voltage. Figure 7 shows the normalized count number of the self-organized nanochannel arrays with different circularities obtained with the one-step, three-step, and multi-electrolyte-step AAO methods. The three-step and multi-electrolyte-step AAO methods can achieve better circularity distribution at about 0.87, which is higher than the one-step AAO method of 0.85. If we consider all of the process parameters, we can find that the initial thickness of the aluminum for the multi-step AAO method is about 6 μm which is thicker than the thickness obtained with the multi-electrolyte-step AAO method, which is about 2 μm.

ChenChun-Ko; ChenSheng-Hui · Multi-electrolyte-step anodic aluminum oxide method for the fabrication of self-organized nanochannel arrays ↗ · Feb 14, 2012 · Källans villkor

Table 1 shows all the parameters for the self-organized nanochannel arrays obtained with one-step, multi-step, and multi-electrolyte-step AAO methods. The periods and the diameters of the interpores can also be analyzed using image processing. The periods of the nanochannel arrays can be calculated from the FFT image of the SEM images [16]. The average periods are 203 ± 35 nm, 206 ± 15 nm, and 202 ± 20 nm for the one-step, multi-step, and multi-electrolyte-step AAO methods, respectively. Because the periods are all controlled by the first applied voltage, the results are similar. However, the one-step method is the most irregular of all the methods. Analysis of the diameters of the interpores, as seen in Figure 8, shows the normalized count number of the self-organized nanochannel arrays of the average diameters obtained with the one-step, three-step, and multi-electrolyte-step AAO methods. We can find that the average diameter is largest with the multi-electrolyte-step AAO method because a lower applied voltage can provide a thinner Al2O3 barrier layer. Table 1 shows a comparison of the results of the one-step, multi-step, and multi-electrolyte-step methods. It can be seen that the multi-electrolyte-step AAO method has the advantages of a shorter processing time, high quality of nanochannel, and low applied power.