Templating using Lyotropic Liquid Crystals

Membrane templating is capable of producing a range of structures in various sizes. However, the degree of control is not at the molecular scale. An alternative templating method that has molecular-level control over the pore size and the ability to produce ordered arrays of pores is lyotropic liquid crystal templates [53]. Lyotropic liquid crystals are surfactant phases produced at high percentages of surfactant to solvent. 

There has been a range of materials that have been templated by lyotropic liquid crystals other than platinum including polymers [55], Pd [56], Zn [57], Cd [57], Ni [58], 

The high surface areas of these electrodes make them ideal for electroanalytical applications where the high surface area is exploited to improve detection limits and/or detection range. Evans et al. [61] have demonstrated the production of platinum mesoporous electrodes and their application into the detection of H2O2. 

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Another polymer-mediated synthesis used a lyotropic liquid-crystal (LLC) template to obtain 4- to 7-nm crystalhtes of Pd (Ding and Gin, 2000). In this study, Pd2+ was ion exchanged into the channels of a cross-linked LLC and reduced with H2. The resultant catalysts were found to be active for efficient hydrogenation of benzaldehyde. 

Ding, J. H., and Gin, D. L., Catalytic Pd nanoparticles synthesized using a lyotropic liquid crystal polymer template, Chem. Mater. 12,22 (2000). 

Thermotropic liquid crystals and also lyotropic liquid crystals generate functional molecular assemblies. lyotropic liquid crystalline phases are exhibited by amphiphilic molecules in appropriate solvents. They form nano-segregated structures because the molecular structures consist of hydrophilic and hydrophobic components. In Chapter 6, Gin and co-workers describe how lyotropic liquid crystals may be used to form functional materials. Lyotropic liquid crystals can act as templates for inorganic materials, ion conductors, catalysts, drug delivery systems, and nanofilters. 

Cosutchi Andreea Irina, Hulubei Camelia, Stoica luliana, and loan Silvia. A new approach for patterning epiclon-based polyimide precursor films using a lyotropic liquid crystal template. J. Polym. Res. 18 no. 6 (2011) 2389-2402. 

A new approach for patterning polyimide, starting from its precursor, consists in using a lyotropic liquid crystal template,, namely hydrox) ropyl cellulose (HPC), which under... 

The lamellar lyotropic liquid crystal phase is often formed in detergent solutions. When subjected to shear lamellae can, under certain conditions, curve into closed shell structures called vesicles (Section 4.11.4). These are used in pharmaceutical and cosmetic products to deliver molecules packed into the core. Selective solubilization in micelles finds similar applications, although micelles tend to break down more rapidly than vesicles when diluted. Applications for hexagonal and cubic structures may stem from the recent discovery that they can act as templates for inorganic materials such as silica, which can be patterned into an ordered structure with a regular... 

Traditionally, mesoporous metals have been elaborated by using mesoporous silica as a hard template. In 1997, Attard s research group first reported that mesoporous platinum can be produced by the chemical or electrochemical reduction of metal salts dissolved in the aqueous domains of a hexagonal lyotropic liquid crystal (LLC) phase architecture. " They have shown that the reduction of platinum salts in this system led to platinum whose nanostructure was a cast of the LLC... 

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