Interface and solution properties of alkyl ethoxylate with distributed oxyethylene chain

Abstract

The three type of dodecyl 9 ethoxylate(LAE-9) with different oxyethylene distribution (NRE, BRE, XBRE) are investigated about surface properties and mixed micelle properties between sodium dodecyl ben-zene sulfonate in this study. The three type of tridecyl 10 ethoxylate(TDE-10), three type of dodecyl 7 ethoxylate(LAE-7), and three type of nonyl phenol 10 ethoxylate(NPE-10) are investigated about prediction of cloud point. The hydrotalcity type catalyst was used to produce narrow range ethoxylate (NRE). The BRE was produced by traditional alkali catalyst and XBRE was produced mixture of normal distribution ethoxylate used traditional alkali catalyst. Polydispersity index (PDI) is defined as the weight-averaged molecular weight of polyoxyethylene divided by the number-average molecular weight. The solution and interfacial properties of ethoxylated nonionic surfactant with different polydispersity are studied over equilibrium surface tension and dynamic surface tension. The polyoxyethylene distribution affects the surface properties such as CMC, equilibrium surface tension, dynamic surface tension and head group area. Three different series(such as NRE-9, BRE-9 and XBRE-9) are measured about the CMCs which were lowered with increasing the polyoxyethylene distribution. The cross sectional surface areas of LAE-9 also varied with the polyoxyethylene distribution(PDI). The CMC and cross sectional surface areas decrease according to the increasing PDI because of short chain ethoxylate in the LAE-9s. The diffusion coefficients increase with the increasing the PDI. The effects of distributed ethoxylate chain on the properties of mixed micelles formed by anionic DBS (do-decyl benzene sulfonate) and maximum synergism point of the distributed nonionic LAE-9 (lauryl alcohol ethoxylate, LAE series) were investigated. The critical micelle concentration (CMC) for micelles composed of dispersed polyoxyethylene decreased as the polydispersity index (PDI) increased accordi...