Adsorption Kinetics of a Cationic Surfactant Bearing a Two-Charged Head at the Air-Water Interface

被引：3

作者：

Fernandez Leyes, Marcos ^{[1
]}

Gimenez Reyes, Santiago ^{[1
]}

Cuenca, Ezequiel ^{[1
]}

Sanchez Morales, Jhon F. ^{[1
]}

Ritacco, Hernan ^{[1
]}

机构：

[1] UNS, CONICET, Inst Fis Sur IFISUR, Dept Fis, Ave LN Alem 1253,B8000CPB, Bahia Blanca, Buenos Aires, Argentina

来源：

COATINGS | 2020年 / 10卷 / 02期

关键词：

cationic surfactants; Gemini; 12-2-12; surfactant; dynamic surface tension; maximum bubble pressure; surface potential; GEMINI SURFACTANTS; DILATIONAL VISCOELASTICITY; POLYELECTROLYTE SOLUTIONS; COUNTERION CONDENSATION; LIMITING LAWS; TENSION; MONOLAYERS; RHEOLOGY; BEHAVIOR;

D O I：

10.3390/coatings10020095

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

We studied the dynamics of adsorption at the air-water interface of a cationic surfactant bearing two charges, Gemini 12-2-12, at concentrations below and above the critical micelle concentration (cmc). We used maximum bubble pressure and Wilhelmy plate techniques in order to access all time scales in the adsorption process. We found that the adsorption dynamics are controlled by diffusion at the initial stage of the adsorption process (milliseconds) and it is kinetically controlled by an electrostatic barrier (minute) approaching the equilibrium surfactant surface concentration. Between these two extremes, we found several relaxation phenomena, all following exponential decays with characteristic times spanning from one to hundreds of seconds. By means of time-resolved surface potential measurements, we show that these processes involve charge redistribution within the interfacial region. The surface tension data are analyzed and interpreted in the framework of the free energy approach.

引用

页数：16