Double photo-responsive aluminum oxide nano channel based on N3 and spiropyrane molecular modification and preparation method thereof

[0035] Example 1

[0036] This embodiment is an hourglass-type alumina nanochannel system. The hourglass-type alumina nanochannel film is prepared by an oxalic acid solution anodizing method, the oxidation voltage is 50V, and the hourglass-type structure is obtained by in-situ expansion using current monitoring; The thickness of the hourglass-type alumina nanochannel film is about 98um; the pore diameter at both ends of the hourglass-type alumina nanochannel film is about 35nm, and the middle pore diameter is about 10nm.

[0037] The preparation of the hourglass alumina nanochannel adopts a combination of double-sided anodization and in-situ hole expansion. The specific operation steps are as follows:

[0038] (1) A flat aluminum sheet with a purity of 99.999% and a thickness of about 100 μm is ultrasonically cleaned with acetone, absolute ethanol and high-purity water for 5 minutes, and then electrochemically polished in a mixture of perchloric acid and ethanol (1:4). The polishing time was 5 minutes, the polishing voltage was 17V, the aluminum sheet was the anode, and the stainless steel sheet was the cathode, and the temperature was maintained at 4°C.

[0039] (2) The first anodic oxidation reaction was carried out in 0.3M oxalic acid solution, the anodic oxidation voltage was 50V, and the temperature was kept at 5°C. It is worth noting that during this period, both sides of the aluminum sheet were oxidized to the cathode for 1 hour.

[0040] (3) Place the sample of primary anodic oxidation in a mixed solution of 6wt% phosphoric acid and 3.5wt% chromium trioxide at 90°C for 4 hours. The oxide layer generated by the primary oxidation is etched away, leaving uniform surfaces on both sides of the aluminum sheet. Pits.

[0041] (4) A second anodic oxidation is carried out after the oxide layer is corroded. The oxidation conditions are the same as the primary oxidation. During this process, alumina nanotubes grow on both sides of the aluminum sheet at the same time until the anodic oxidation current is almost zero, and the aluminum matrix is ​​completely It is oxidized to aluminum oxide, and the barrier layers of two rows of aluminum oxide nanotubes that grow oppositely meet at the middle position.

[0042] (5) Finally, the aluminum oxide nanotube film prepared in the previous step is still immersed in the electrolyte oxalic acid solution for 30 minutes to expand the holes in situ to open the middle barrier layer. In this way, after 30 minutes of in-situ etching, part of the intermediate barrier layer was etched into small holes, and both sides of the aluminum oxide nanotubes were large hole ends, and the hourglass-type aluminum oxide nanochannel membrane was prepared.

[0043] A picoammeter is used as a control circuit to perform circuit-voltage (IV) performance testing on the hourglass alumina nanochannel; wherein the electrolyte solution is a KCl solution with a concentration of 1 mM/L and a pH of 3; the alumina The voltage scanning range of the nanochannel is from -2V to +2V, and the curve of the ion current fluctuating with the fluctuation of the applied voltage is obtained. The tested IV curve is linear. The hourglass alumina nanochannel film is symmetrical. The structure and charge distribution show non-rectifying characteristics.

[0044] Example 2:

[0045] A solution method is used to modify the APTES molecules on the hourglass-type alumina nanochannel.

[0046] The picoammeter was used as the control circuit to perform IV performance test on the hourglass alumina nanochannel modified by the APTES molecule; wherein the electrolyte solution was a KCl solution with a concentration of 1 mM/L and the pH of the solution was 3; the APTES molecule was modified The voltage scanning range of the hourglass alumina nanochannel is from -2V to +2V, and it is concluded that the ion current fluctuates with the fluctuation of the applied voltage, such as figure 1 As shown, the tested I-V curve is linear, so the alumina nanochannel modified by the APTES molecule has no ion rectification characteristics.

[0047] The contact angle measurement of the alumina nanochannel and the alumina nanochannel modified with APTES shows that the bare-hole alumina nanochannel is more hydrophilic ( figure 1 In the middle b and c are the contact angles of the upper and lower surfaces respectively); after the alumina nanochannel is modified with APTES, the modified alkyl chains on the surface and the inner wall of the channel increase the hydrophobicity of the channel ( figure 1 In d and e), the ion current of the channel is reduced due to the reduction of the effective pore size after modification.

[0048] Example 3:

[0049] A solution method is used to perform single-sided modification of N3 molecules on the alumina nanochannel modified by APTES.

[0050] Using the picoammeter as the control circuit, the IV performance test was performed on the hourglass-type alumina nanometer modified on one side of the N3 molecule; wherein the electrolyte solution was a KCl solution with a concentration of 1 mM/L and a pH of 3; the N3 The voltage sweep range of the hourglass alumina nanochannel modified on one side of the molecule is from -2V to +2V, and the results are as follows figure 2 , It is concluded that the ion current fluctuates with the fluctuation of the applied voltage, and the tested IV curve is non-linear. Therefore, the hourglass-type alumina nanochannel modified by the single side of the N3 molecule exhibits ion rectification characteristics, that is, the voltage is at -2V In the negative voltage region to +0V, a larger current is exhibited, and the hourglass alumina nanochannel exhibits an "on" state; in the positive voltage region from 0V to +2V, a smaller current is exhibited, so The hourglass-type alumina nanochannels are shown in the "off" state. A solar simulator is used to perform visible light (Vis on curve) and ultraviolet light (UV on curve) treatments on the alumina nanochannel modified on one side of the N3 molecule. There is little difference between the IV curve of ultraviolet light and visible light. The rectification direction of the tested IV curve remains unchanged, but the current increases significantly, that is, in the voltage range from -2V to +2V, the current value is larger than that in the dark state (Dark curve). It shows that the hourglass-type alumina nanochannel modified on one side of the N3 molecule has light responsiveness.