Lyotropic liquid-crystal template

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. 

Figure 1.15 TEM image of Pt nanoparticles that have been produced by lyotropic liquid crystal templating. Porous structures can be seen and are spaced in an hexagonal array. (Reprinted with permission from Ref [54], 1997 Wiley-VCH Verlag GmbH, Co. KCaA.)...

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... 

Fleischmann EK, Forst FR, Zentel R (2014) Liquid-crystalline elastomer fibers prepared in a microfluidic device. Macromol Chem Phys 215 1004-1011 Flory PJ (1956) Phase equilibria in solutions of rod-like particles. Proc R Soc Lond A 234 73-89 Forney BS, Guymon CA (2011) Fast deswelling kinetics of nanostructured poly (N-isopropylacrylamide) photopolymerized in a lyotropic liquid crystal template. Macromol Rapid Commun 32 765-769... 

Zhao, D.-D. Xu, M. W. Zhou, W.-J. Zhang, J. Li, H. L. Preparation of ordered mesoporous nickel oxide film electrodes via lyotropic liquid crystal templated electrodeposition route. Electrochim. Acta 2008, 53, 2699-2705. 

Bender F, Mankelow RK, Hibbert DB, Gooding JJ (2006) Lyotropic liquid crystal templating of roups 11 and 12 metal films. Electroanalysis 18 1558-1563... 

Goltner, C. G Henke, S. Weissenberger, M. C. Antonietti, M. 1998. Mesoporous silica from lyotropic liquid crystal polymer templates. Angew. Chem. Int. Ed. 37 613-616. 

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],... 

Since the first synthesis of mesoporous M41S alumosilicates in 1992 [1,2] numerous systems of mesoporous materials have been reported. The principle method of these syntheses consists of the utilisation of lyotropic liquid crystals as supramolecular templates, which act as structure directing agents in order to mesostructure inorganic building units. 

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). 

In Attard s approach, tetramethylorthosilicate (TMOS) was hydrolyzed and condensed in the aqneons domain of the liqnid crystal phase at pH of abont 2, leading to mesostmctured hexagonal, cubic, or lamellar sihca. Methanol from the hydrolysis of TMOS destroys the long-range order of the liquid crystal however, upon the removal of methanol, the lyotropic liquid crystal is restored and serves as the template phase for the further condensation of silicates. The resnlting pore system replicates the shape of the lyotropic mesophase, so this process is also termed nanocasting . 

Extension of the molecular sieves to the mesoporosity range is possible nsing lyotropic liquid crystal mesophases (Figine 25.20) as removable templates. These mesophases result from the self-assembly of surfactants or amphiphilic molecules and can be thermally or chemically eliminated after the formation of the inorganic network. This approach enables the preparation of materials exhibiting an ordered... 

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