摘要
通过改变液体金属在NaOH溶液中所处的环境介质,利用石墨电极对其施加电场,研究了液态金属的表面张力、界面电化学反应、氧化膜的产生、溶液中电润湿等动态过程。实验发现Wood合金液滴在阳极发生电化学反应产生的氧化膜会迅速减小表面张力并发生铺展,在阴极发生还原反应会使带氧化膜的金属在3 s内恢复到原状,电毛细作用力使氧化膜破裂,各氧化物与NaOH反应产生Sn(OH)_6^(2-)、SnO_3^(2-)、SnO_2^(2-)、PbO_3^(2-)、Cd(OH)_4^(2-)使溶液的颜色发生改变,溶液中生成Bi2O3-Bi(OH)3白色共聚物。薄膜电介质层润湿和溶液中电润湿机理在本质上相同,表面张力随着电压的增大而减小并发生明显的电润湿铺展过程,但由于金属液滴通过电化学反应所能吸附的OH-数量有限,润湿角存在饱和性。
By variation of liquid Wood metal＇s environment in Na OH solution and application of electric field with graphite electrode, surface tension of the liquid metal, interfacial electrochemical reaction, generation of oxidation film, and other dynamic processes were studied. The results showed that thin oxidation film on the surface of Wood alloy droplets which was formed by anodic oxidation reaction quickly reduced surface tension of Wood alloy and the oxidation film on surface of liquid alloy droplets would return to neutral state by cathodic reduction reaction within 3 seconds. The electrical capillary force broke the oxide film so that metal oxides reacted with Na OH to generate ions of Sn（OH）_6-（2-）、SnO_3-（2-）、Sn O_2-（2-）、PbO_3-（2-）、Cd（OH）_4-（2-） which altered solution colors with a white precipitate of Bi_2O_3-Bi（OH）_3 copolymer. The dielectric wetting and solution electrowetting on thin film essentially had the same mechanism. With the increase of voltage, the surface tension was decreased and electrowetting spreading process was occurred obviously, but the wetting angle exhibited saturation as a result of limited number of OH-ions adsorbed on alloy droplets by electrochemical reactions.
出处
《化工学报》
EI
CAS
CSCD
北大核心
2017年第3期1122-1128,共7页
CIESC Journal
基金
国家自然科学基金项目(51665031)
甘肃省杰出青年基金项目(1506RJDA087)~~
关键词
氧化
还原
电化学
界面张力
电解质
微流体学
oxidation
reduction
electrochemistry
interfacial tension
electrolyte
microfluidics
作者简介
第一作者：张国堤（1992-），男，硕士研究生。
