DIFFUSION-CONTROLLED SURFACTANT ADSORPTION STUDIED BY PENDANT DROP DIGITIZATION
DIFFUSION-CONTROLLED SURFACTANT ADSORPTION STUDIED BY PENDANT DROP DIGITIZATION
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DOI：
10.1002/aic.690361202
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发表时间：
1990-12-01
期刊：
影响因子：
3.7
通讯作者：
MALDARELLI, C
中科院分区：
文献类型：
--
作者：
LIN, SY;MCKEIGUE, K;MALDARELLI, C
视频图像数字化增强的垂滴张力测量技术是一种有效的实验方法，可用于测量表面活性剂在流体界面上吸附引起的界面张力松弛。用这种方法测量了扩散控制的非离子型聚氧基表面活性剂的表面张力弛豫曲线。通过与表面活性剂扩散方程的数值解和弗鲁姆金平衡吸附等温线的比较，计算了扩散系数。这个比较是在整个放松期进行的。与目前仅利用弛豫谱的短段或长段部分的技术相比，这种方法建立了一个更可重复的扩散系数。此外，通过将混合扩散和表面动力学传递的数值解与扩散限制的结果进行比较，推导了聚氧基表面活性剂吸附过程动力学常数的下界。
Pendant drop tensiometry enhanced by video-image digitization is shown to be a useful tool for the experimental measurement of the relaxation in interfacial tension due to the adsorption of surfactant at a fluid interface. Using this method, profiles of the relaxation in surface tension of a diffusion-controlled, nonionic polyethoxy surfactant were measured. A diffusion coefficient was computed by comparing these profiles with numerical solutions of the bulk surfactant diffusion equation and a Frumkin equilibrium adsorption isotherm. This comparison was made for the entire relaxation period. This method establishes a more reproducible diffusion coefficient than current techniques that utilize only the short- or long-time parts of the relaxation spectrum. In addition, lower bounds on the kinetic constants for the sorption process are inferred for the polyethoxy surfactant used by comparing numerical solutions of mixed diffusion and surface kinetic transfer with the diffusion-limited result.