Impact of molecular structure, headgroup and alkyl chain geometry, on the adsorption of the anionic ester sulfonate surfactants at the air-solution interface, in the presence and absence of electrolyte

JOURNAL OF COLLOID AND INTERFACE SCIENCE

卷:544

Article

Wang, Zi^1,2  Li, Peixun²  Ma, Kun²  Chen, Yao²  Campana, Mario²  Penfold, Jeffrey^2,3  Thomas, Robert K.³  Roberts, David W.⁴  Xu, Hui⁵  Petkov, Jordan T.⁶  Yan, Zifeng¹ 

[1] China Univ Petr, Sch Sci, State Key Lab Heavy Oil Proc, Qingdao 266580, Shandong, Peoples R China

[2] Rutherford Appleton Lab, ISIS Facil, STFC, Didcot OX11 0QX, Oxon, England

[3] Univ Oxford, Phys & Theoret Chem Lab, South Parks Rd, Oxford OX1 3QZ, England

[4] Liverpool John Moores Univ, Sch Pharm & Biomol Sci, Liverpool L3 3AF, Merseyside, England

[5] Menara KLK, KLK Oleo, SDN BDH, Petaling 47810, Jaya Selanger, Malaysia

[6] Lonza UK, GB Blackley, Manchester M9 8ES, Lancs, England

关键词: Ester sulfonate anionic surfactants;    Adsorption;    Air-solution interface;    Neutron reflectivity;    Surface multilayers;   

DOI  :  10.1016/j.jcis.2019.03.011

来源: Elsevier

【 摘 要 】

The transition from monolayer to multilayer adsorption at the air-water interface in the presence of multivalent counterions has been demonstrated for a limited range of anionic surfactants which exhibit increased tolerance to precipitation in the presence of multivalent counterions. Understanding the role of molecular structure in determining the transition to surface ordering is an important aspect of the phenomenon. The focus of the paper is on the alkyl ester sulfonate, AES, surfactants; a promising group of anionic surfactants, with the potential for improved performance and biocompatibility. Neutron reflectivity measurements were made in aqueous solution and in the presence of NaCl, CaCl2, MgCl2 and AlCl3, for a range of alkyl ester sulfonate surfactants, in which the headgroup and alkyl chain geometries were manipulated. In the regions of monolayer adsorption changing the AES headgroup and alkyl chain geometries results in an increased saturation adsorption and in a more gradual decrease in the adsorption at low concentrations, consistent with a greater adsorption efficiency. Changing the AES headgroup and alkyl chain geometries also results in changes in the transition from monolayer adsorption to more ordered surface structures with the addition of AlCl3 and mixed multivalent electrolytes. A more limited surface layering is observed for the ethyl ester sulfonate, EES, with a C-14 alkyl chain. Replacing the C-14 alkyl chain with a C-18 isostearic chain results in only monolayer adsorption. The results demonstrate the role and importance of the surfactant molecular structure in determining the nature of the surface adsorption in the presence of different electrolytes, and in the tendency to form extended surface multilayer structures. (C) 2019 Elsevier Inc. All rights reserved.

【 授权许可】

Free