The role of charged surfactants in the thermal and structural properties of lyotropic liquid crystalline mesophases of [Zn(H2O)6](NO3)2?CnEOm?H2O

Abstract

a b s t r a c tThe mixtures of [Zn(H 2 O) 6 ](NO 3 ) 2 salt, 10-lauryl ether (C 12 H 25 (OCH 2 CH 2 ) 10 OH, represented as C 12 EO 10 ), a charged surfactant (cetyltrimethylammonium bromide, C 16 H 33 N(CH 3 ) 3 Br, represented as CTAB or sodium dodecylsulfate, C 12 H 25 OSO 3 Na, SDS) and water form lyotropic liquid crystalline mesophases (LLCM). This assembly accommodates up to 8.0 Zn(II) ions (corresponds to about 80% w/w salt/(salt + C 12 EO 10 )) for each C 12 EO 10 in the presence of a 1.0 CTAB (or 0.5 SDS) and 3.5 H 2 O in its LC phase. The salt concentration can be increased by increasing charged surfactant concentration of the media. Addition of charged surfactant to the [Zn(H 2 O) 6 ](NO 3 ) 2 -C 12 EO 10 mesophase not only increases the salt content, it can also increase the water content of the media. The charged surfactant-C 12 EO 10 (hydrophobic tail groups) and the surfactant (head groups)-salt ion (ion-pair, hydrogen-bonding) interactions stabilize the mesophases at such salt high and water concentrations. The presence of both Br À and NO

Origin of Lyotropic Liquid Crystalline Mesophase Formation and Liquid Crystalline to Mesostructured Solid Transformation in the Metal Nitrate Salt−Surfactant Systems

“…The surface charge of the molten phase, in the molten−surfactant interface, cannot be balanced above 70 w/w% even in the cubic mesophase. However, the addition of a charged surfactant into the media stabilizes the columnar phase up to 80 w/w% ZnX−C 12 EO 10 . Based on our observations, we believe that the salt species are in the molten phase in the hydrophilic domains of the mesophase, acting as the solvent (ionic liquid) of the media.…”

Synthesis of mesoporous LiMn2O4and LiMn2−xCoxO4thin films using the MASA approach as efficient water oxidation electrocatalysts

“…This is a known behavior in salt-surfactant mesophases in the presence of CTAB. 49 Our previous work showed that increasing the amount of CTAB shrinks the unit cell; however increasing the amount of salt enlarges the unit cell in the mesophase. 49 Therefore, the charged surfactant content of the mesophase determines the volume of the hydrophilic domains of the mesophase for the salt species; for samples with higher salt concentrations, the CTAB amount should be further increased to obtain a stable mesophase.…”

Salt‐Acid‐Surfactant Lyotropic Liquid Crystalline Mesophases: Synthesis of Highly Transparent Mesoporous Calcium Hydroxyapatite Thin Films

“…It is already known from the salt-surfactant system that increasing the salt/surfactant ratio expands the unit cell of the mesophase to accommodate more salt species. [43] Therefore, the new behaviour (no change in the unit cell) can be interpreted as a decrease in the aggregation number of the surfactant, that is, the number of surfactants per unit volume, in the mesophase to accommodate more aqueous species per surfactant. Therefore, the content of the hydrophilic domains likely does not change much with increasing aqueous species in the media.…”