Development of Portable Experimental Apparatus on Education of Polymer Physics

将超临界流体技术与电镀技术相结合，开发了一种新型电镀技术“可持续超临界纳米电镀”。该工艺是在含有表面活性剂的超临界二氧化碳（CO_2）和电镀液的乳液中进行电镀反应。用这种方法镀的薄膜没有任何针孔，这些针孔是由电解水产生的氢泡造成的。与仅从溶液中电镀相比，该方法制备的镍膜质量更高，均匀性更高，晶粒尺寸更小（11.1nm），维氏硬度显著提高。此外，还测定了在添加少量表面活性剂的乳液中，CO_2体积分数对电流效率和电阻值的影响。结果表明，浓CO_2浓度大于CO_2临界点，有利于形成电镀反应乳化液。根据电导率的测定，在CO_2体积分数为0 ~ 80%的范围内，将乳液划分为CO_2在水中（C/W）型。含有超临界二氧化碳的乳液的不连续电化学反应可能是镀层获得如此优异性能的重要原因。

An innovative electroplating technology "Sustainable Supercritical Nanoplating (SSNP)", which is a hybrid of supercritical fluid and electroplating technology, has been developed. In this technology, electroplating reactions are carried out in emulsion of supercritical carbon dioxide (CO_2) and electroplating solution with surfactants. The plated film by this method did not have any pinholes, which come from hydrogen babbles produced by the electrolysis of water. Compared to electroplating from the solution only, higher quality nickel films have been prepared by this method, which have higher uniformity, smaller grain size (11.1nm), and significantly higher Vickers hardness. Moreover, the current efficiency and electric resistance value were measured as a function of CO_2 volume fraction in the emulsion with few kinds of surfactants. These results show that dense CO_2 beyond critical point of CO_2 is effective to form emulsion for the electroplating reaction. On the basis of the electrical conductivity measurements, the emulsion was classified into CO_2 in water(C/W) type in the wide range of the CO_2 volume fraction from 0 to 80 %. The discontinuous electrochemical reaction of the emulsion including supercritical carbon dioxide might play an important role to attain such excellent properties of the plated film.