Study On The Effect Of Ultrasonic Method On Preparation Of Nano - Bubbles And Their Electrode Double Electrode

In recent years,the interfacial phenomenon is becoming more and more difficult and hot spots for the researchers.The discovery of nanobubbles resulted from research into the long range hydrophobic attractive force(LRHAF) between hydrophobic bodies in aqueous solution. However, in the classical thermodynamic theory, the nanobubbles are considered to be unstable at room temperature in water. In the past few years, with the more researches on hydrophobic surface, many phenomenons support the presence of nanobubbles on solid-liquid interface. The existence of nanobubbles has been proved by neutron reflection(NR) and atomic force microscope(AFM), the most important that imaging by AFM, confirm the existence of nanobubbles effectively.Now the most powerful means of direct detection of solid-liquid interface nanobubbles is atomic force microscope(AFM).While image nanobubbles by AFM, the flat substrates were usually used, such as highly oriented pyrolytic graphite(HOPG), mica, gold, polystyrene and so on. So far, the formation of nanobubbles has been examined in some experiments, some methods have been established to intentionally produce a large number of nanobubbles, such as exchanging alcohol-water, exchange of two different solvent, direct dropping, direct immersing, liquid heating and electrochemical reaction. The method of exchanging alcohol-water was used to generate nanobubbles widely and proved to be an effective method that can generate large amount nanobubbles on varied surfaces with high repetitively. However some plat substrates which are soluble in the organic solvent or easy to introduce organic contamination to the system. In order to overcoming the these shortages, we have to find some new methods to generate nanobubbles. Ultrasonic give us inspiration.Through the combination of method for producing nanobubbles by ultrasonic and electrochemical workstation, the cyclic voltammetry curves of the glassy carbon electrode were tested. In our experiment, we used the degassing electrolyte solution and the electrolyte solution, and compared the results of two experiments to draw the formation of nanobubble. We used degassing and undegssing water in our experiments. We can know that nanobubbles generated through compare the two results of experiments. We also studied how the ultrasonic time effect the generation of nanobubbles. Experimental results show that the ultrasonic time is longer, the capacitance of electric double layer were falling, until changes smoothly, according to the obtained nano bubbles with ultrasonic time to increase the coverage area of more and more big. The electrode effect of ultrasonic frequency, with the increase of ultrasonic frequency, the capacitance of electric double layer has been reduced, until the change stable, according to the double layer capacitor combining the theoretical and experimental results, we conclude that the increase of ultrasonic frequency relative dielectric constant decreases, so nano bubbles constantly covered electrode surface. The ultrasonic frequency size of nano bubble formation also has a great relationship, with the increase of ultrasonic frequency, capacitance in time drop, nano bubbles in the constantly increasing coverage area click in constant change.In addition, we also used the traditional method to replace alcohol water nano bubbles on the surface of glassy carbon electrode, and electrochemical workstation to test the effect of electrode. By the exchange of ethanol and water was measured before and after the replacement replacement capacitor, is found after the replacement capacitor becomes small, according to the theoretical derivation and experimental results after the replacement, alcohol and water on the glassy carbon electrode produces nano bubbles. We used the degassed water and alcohol, degassing degassing of the electrolyte solution to do the above experiments before and after the replacement replacement found capacitance change is very small. This proved that the alcohol water substitution method can also produce nano bubbles on the surface of glassy carbon electrode and can be used to test its effect on electrochemical electrode size.