Kim JY, Song MG, Kim JD
Department of Chemical Engineering, Korea Advanced Institute of Science and Technology, Taejon, Kusong-dong, Yusong-gu, 305-701, Republic of Korea
J Colloid Interface Sci. 2000 Mar 15;223(2):285-291. doi: 10.1006/jcis.1999.6663.
A simple and convenient method to measure microelectrophoretic mobilities was proposed to determine the zeta potential of nanobubbles generated by ultrasonication. Bubbles in pure water solutions and in aqueous solutions of alkyl polyglycoside (AG) with different alkyl chain lengths and degrees of polymerization in the head group were sonicated with a palladium-coated electrode designed specially by the manufacturer. The zeta potentials of bubbles with ordinary cationic and ionic surfactants are consistent with others' previous results. The average size of the bubbles generated by sonication is in the range of 300 to 500 nm. The zeta potentials of bubbles in both pure water and AG solutions at all pH values are negative. As the chain length of AG increases, zeta potentials significantly decrease at high pH. For nonionic AG, a possible charging mechanism based on known mechanisms is suggested to explain the negative charge, known to be unusual. Even with a very high concentration of H(+) ions in solution the bubbles are charged negatively because the interface is covered with slightly acidic alcohol groups of AGs. At high pH, the less polar the surfactant, the more negative the charge, since nonpolar surfactant molecules induce the adsorption of OH(-) ions, rather than H(+) ions that prefer hydration by water molecules. Copyright 2000 Academic Press.
提出了一种简单便捷的方法来测量微电泳迁移率，以确定超声处理产生的纳米气泡的ζ电位。使用制造商专门设计的镀钯电极，对纯水以及含有不同烷基链长度和头基聚合度的烷基多糖苷（AG）水溶液中的气泡进行超声处理。普通阳离子和离子表面活性剂形成的气泡的ζ电位与其他人之前的结果一致。超声处理产生的气泡的平均尺寸在300至500纳米范围内。在所有pH值下，纯水和AG溶液中气泡的ζ电位均为负。随着AG链长度的增加，在高pH值下ζ电位显著降低。对于非离子型AG，基于已知机制提出了一种可能的充电机制来解释这种负电荷，这一情况较为罕见。即使溶液中H(+)离子浓度非常高，气泡仍带负电，因为界面被AG的微酸性醇基团覆盖。在高pH值下，表面活性剂的极性越小，电荷越负，因为非极性表面活性剂分子会诱导OH(-)离子吸附，而不是优先被水分子水化的H(+)离子吸附。版权所有2000年学术出版社。
