Surfactant alkyl chain length

Fig. 4.6 Correlation of relative dynamic surface pressures with foam kinetics data dh/dt as a function of the type of surfactant, alkyl chain length and salt concentration [47],...

Measurement of K for NBF from solution of four homologues of the cationic surfactants alkyltrimethylammonium chlorides [488] indicated that K decreased with increasing surfactant alkyl chain length. 

Shin, M., Barrington, S. F., Marshall, W. D., and Kim, J. W. (2005). Effect of surfactant alkyl chain length on soil cadmium desorption using surfactant/ligand systems. Chemosphere 58(6), 735-742. 

In an analogous approach to those discussed above, Klok, Mezzenga, and co workers prepared bioinspired complexes by ionic complexation of hyperbranched polypeptides and surfactants [113] that lead to columnar hexagonal or lamellar mesophases, as a function of surfactant alkyl chain length [113]. 

Lindell, K. and Engstrom, S., Investigation of surfactant alkyl chain length and counterion effects on the thermogelling EHEC system, Int. J. Pharm., 124, 107-118 (1995). 

In the presence of a polymer, the surfactant chemical potential is lowered with respect to the situation without polymer (Figure 20.6). There are several interactions which can be responsible for surfactant binding or a polymer-induced micellization. We note that in many respects (variation with surfactant alkyl chain length, solubilization, micelle structure and dynamics) there is a close similarity to the micellization of the surfactant alone. The normal hydrophobic interaction between the alkyl chains must therefore still be a dominating contribution to the free energy of association. However, it is modified by mainly one of the following two factors. 

The extent of phase separation in the system shown in Figure 20.21 increases strongly with the surfactant alkyl chain length and polymer molecular weight. On addition of electrolyte, the phase separation is eliminated, but at higher electrolyte content there is a phase separation again. However, as we can see in Figure 20.22, it is of a different nature. This behaviour, which is... 

DEL DeLisi, R., Lazzara, G., Milioto, S., and Muratore, N., Thermodynamics of aqueous poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide)/surfactant mixtures. Effect of the copolymer molecular weight and the surfactant alkyl chain length, J. Phys. Chem. B, 108, 18214, 2004. 

Fig.4a XRD pattern of Mo-oxide surfactant Fig.4b Dependence of the (001) d-spacing synthesised with hexadecyltrimethyl- on the surfactant alkyl chain length...

Our group [38] measured isotherms for the cationic C TAB surfactant in various ILs toward understanding the role of the IL. The ILs studied included those with imidazolium, pyrrolidinium, and ammonium cations with varied anions. This study identified CMC values by solubility measurements in addition to isotherms, revealing the key importance of temperature on micellization in ILs. Further, we also confirmed the logarithmic dependence of the CMC with surfactant alkyl chain length (Fig. 2.10). The relative CMC values for the same C TAB in different ILs was adequately described by a mean-field model, lending support for a dominant role of interfacial energy between surfactant and IL and a minimal role of electrostatic effects [38]. 

Figure 4 Precipitation phase diagram for the anionic-cationic surfactant system NaAS-DPC at three different anionic surfactant alkyl chain lengths.

Fluorescence microscopy has been used extensively to monitor the compaction of DNA in the presence of several cationic species [16-23] as well as some other cosolutes [24]. For cationic surfactants, compaction starts at concentrations only slightly above the onset of binding, as characterized by the cac [19] and shows the same dependence of surfactant alkyl chain length as other self-assembly processes [25]. 

---