Controlling the aggregation of sodium dodecylsulphate in aqueous poly(ethylene glycol) solutions

Abstract

The role of PEG's of different molecular weights on the self-assembly of SDS and the role of added NaCl has been addressed opening new scopes for further studies.

Novel application of PEG/SDS interaction as a wettability modifier of hydrophobic carbonate surfaces

“…There is no interaction observed between PEG-400 and SDS in the bulk solution. The results are in a good agreement with previous findings (da Silva et al 2004;Dey et al 2015). Using isothermal titration calorimetry (ITC), Dai and Tam (2001) found that the binding behaviour of PEG and SDS in the bulk solution is dependent on the molecular weights of PEG.…”

“…1, 2, 3, 4 and 5. Surface tension results follow the same trend as previous findings (Cooke et al 1998;Jones 1967;Müller et al 2003;Purcell et al 1998;Umlong and Ismail 2007); however, the previous minimum point, attributed to an SDS impurity (Dey et al 2015;Lin et al 1999;Umlong and Ismail 2007), has not been observed in surface tension measurements. Figure 1 shows that CAC occurs at the SDS concentration of 0.168 g/100 mL (0.7 CMC of free polymer solution).…”

“…Between CAC and CMC, surface tension plots go through a plateau till all binding sites on the polymer chain are occupied and then start to fall again; this point is referred to as the polymer saturation point (PSP). It is confirmed that the surface tension at CAC is dependent on polymer concentration (Dey et al 2015;Jones 1967); however, the surfactant concentration at this point is independent of polymer concentration (Dai and Tam 2001;Jones 1967;Moroi et al 1977). It is worthwhile to mention that in several studies a minimum point was observed in the surface tension isotherm due to the presence of dodecanol as an impurity in the SDS used (Dey et al 2015;Lin et al 1999;Umlong and Ismail 2007).…”

“…This lowers the concentration of lauryl alcohol in the bulk and hence its surface concentration. Consequently, the interfacial tension increases and returns to that of pure SDS solution (Dey et al 2015;Lin et al 1999;Umlong and Ismail 2007). It is possible that small aggregates (pre-micelles) build up below the CAC and CMC, starting at a concentration with a minimum surface tension (Lin et al 1999).…”

“…It has been known that the driving force of the polymersurfactant complex formation is the interaction between anionic head groups of the surfactant aggregation and the ethylene oxide group of polymer (de Alvarenga et al 2004), and both hydrophobic and electrostatic interactions are playing a role in the formation of the polymer-surfactant complex (Dey et al 2015). The well-known structure for these complexes is the necklace model, in which the SDS aggregations are bound to the polymer chain like pearls of a collar (de Alvarenga et al 2004;da Silva et al 2004;Jiang and Han 2000).…”