Interfacial dilational properties of tri-substituted alkyl benzene sulfonates at air/water and decane/water interfaces

• Published in: Journal of colloid and interface science Vol. 327; no. 2; pp. 451 - 458
• Main Authors: Zhang, Lei, Wang, Xiao-Chun, Gong, Qing-Tao, Zhang, Lu, Luo, Lan, Zhao, Sui, Yu, Jia-Yong
• Format: Journal Article
• Language: English
• Published: San Diego, CA Elsevier Inc 15-11-2008; Elsevier
• Subjects: Chemistry; Cole–Cole plot; Colloidal state and disperse state; Dilational elasticity; Dilational viscosity component; Exact sciences and technology; General and physical chemistry; Interface; Sodium alkyl benzene sulfonate; Surface; Surface physical chemistry; Cole–Cole plot; Dilational elasticity; Interface; Dilational viscosity component; Sodium alkyl benzene sulfonate; Surface; Water; Gas liquid interface; Viscosity; Shape; Interface tension; Film; Elasticity; Air water interface; Mechanism; Isomer; Sulfonate; Relaxation; Alkyl; Surface properties; Air; Carbon; Sodium alkyl benzene sulfonate,Surface,Interface,Dilational elasticity,Dilational viscosity component,Cole-Cole plot; Drop; Decane; Analysis method; Sodium; Benzene; Frequency; Physicochemical properties; Rheological properties
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2008.08.019

The dilational rheological properties of absorbed film of three pairs of structural isomers, tri-substituted alkyl benzene sulfonates, at the air–water and decane–water interfaces have been investigated by drop shape analysis method. The influences of bulk concentration on dilational elasticity and viscosity were expounded. Interfacial tension relaxation method was employed to obtain dilational parameters in a reasonably broad frequency range. The experimental results showed that the meta-alkyl to sulfonate group plays a crucial role in the interfacial dilational properties: the longer meta-alkyl will lead to higher dilational parameters for air–water interface and lower ones for decane–water interface when the total alkyl carbon numbers are equal. For alkyl benzene sulfonates with shorter meta-alkyl, the surface dilational properties are similar to interfacial dilational properties, whereas the surface dilational parameters are obviously higher than the interfacial dilational parameters for alkyl benzene sulfonates with longer meta-alkyl in general. The possible mechanism has been proposed and ensured by Cole–Cole plots.
For 377, reorientation process plays more important role at the air–water interface especially at low bulk concentration, and diffusion process will be enhanced in case of decane–water interface.