Lyotropic surfactants

The photoinitiated polymerization of divinylbenzene (DVB) within four separate cubic phases of the system DVB/didodecyl dimethyl ammonium bromide (DDAB) is reported to yield retention of the lyotropic order during the course of the reaction [48], although the structure of the pure polymer matrix after removal of the template was not investigated. Similarly, polymerization of acrylamide within lamellar, hexagonal, and cubic phases of the surfactant Aerosol OT led to preservation of the parental mesostructure [49]. SAXS measurements showed similar diffractograms before and after polymerization, but again there was no report of characterization of the polymer matrix after surfactant removal. Hence, at least in these cases, the formation of a polymer phase within a lyotropic mesophase does not prevent the formation of lyotropic surfactant phases. 

Idziak S H J ef a/1996 Structure under confinement in a smectic-A and lyotropic surfactant hexagonal phase Physica B 221 289-95... 

Stupp and coworkers first prepared mesostructured sulfides with oligomeric alkyl ethylene oxides [89, 90]. Lyotropic surfactant liquid-crystal phases are generated with the addition of appropriate metal ions, for example, Cd +. Hydrogen sulfide or hydrogen selenide gas is then fed into the solution to solidify the mesostructured organic-inorganic composites. The difficulty in this process remains the removal of the surfactants. A family of mesostructured solids, such as CdS, ZnS, and CdSe, have been successfully synthesized. 

Multimodal porous systems in the form of monolithic-shaped forms (bodies) were obtained from a process where a (true) liquid-crystal templating is combined with a sol-gel process [205]. One characteristic of such a process is the incompatibility of lyotropic surfactants with an alcohol, mostly an inherently produced alcohol, which is responsible for the phase separation during the sol-gel processing, stabilizing the resulting monolithic architecture of the monolith [206]. Different approaches use various components, namely, the alcohol source, the silicate sources (both are sometimes combined in one molecule), and molecular or supramolecular templating agents [207]. 

A review describing the state of the art using templates (including lyotropic surfactant phases) to prepare organic polymeric networks has recently been published (406). 

Berret JF, Vermant J, Noirez L (2000b) Lyotropic surfactant nematics under shear neutron scattering in the vortidty plane. In Xlllth international Congress on Rheology, Cambridge (UK), vol 3, pp 273-275... 

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