Liquid crystalline phases in binary surfactant systems

2 Liquid crystalline phases in binary surfactant systems 

It has long been known that structures of the types depicted in Fig. 2.1 may be encountered as the concentration of a surfactant solution is increased. At 

The extent of the mesomorphic phase regions which are encountered at high surfactant concentration, increases with increase in the alkyl chain length in a homologous series of polyoxyethylated non-ionic surfactants. This effect is 

Husson et al. [7] have reported the influence of oxyethylene chain length on the phase behaviour of a series of p-nonylphenol polyoxyethylene derivatives with the general formula C9Hi9C6H40(CH2.CH20) H. Short chain compounds (n = 6 and 8) have neat phase only both neat and middle phases are noted when n = 9, and higher chain length compounds, n = 10 to 15, show a middle phase only. 

A viscous isotropic region has been detected at concentration regions in between the middle and neat phases in some non-ionic systems [7-9]. Fig. 2.3 shows the occurrence of this phase in the N,N,N-trimethylaminododecano-imide-water system which was extensively studied by Clunie et al. [9]. 

---