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Silica Monoliths Templated on L3 Liquid Crystal Abds-Sami Malik,, Daniel M. Dabbs, Howard E. Katz,,| and Ilhan A. Aksay*,
 

Summary: Silica Monoliths Templated on L3 Liquid Crystal
Abds-Sami Malik,, Daniel M. Dabbs, Howard E. Katz,,| and Ilhan A. Aksay*,
Department of Chemical Engineering, Princeton UniVersity, Princeton, New Jersey 08544, and
Bell Laboratories, Lucent Technologies, Murray Hill, New Jersey 08904
ReceiVed June 3, 2005. In Final Form: October 13, 2005
Dimensionally stable, optically clear, highly porous (65% of the apparent volume), and high surface area (up to
1400 m2/g) silica monoliths were fabricated as thick disks (0.5 cm) by templating the isotropic liquid crystalline L3
phase with silica through the hydrolysis and condensation of a silicon alkoxide and then removing the organic constituents
by supercritical ethanol extraction. The L3 liquid crystal is a stable phase formed by the cosurfactants cetylpyridinium
chloride monohydrate and hexanol in HCl(aq) solvent. Extracted 0.5 cm thick disks exhibited a low ratio of scattered
to transmitted visible light (1.5 10-6 at 22 from the surface normal). The degree of silica condensation in the
monolithswashigh,asdeterminedby 29SiNMRmeasurementsofQ3 andQ4 peakintensities(0.53and0.47,respectively).
As a result, the extracted and dried monoliths were mechanically robust and did not fracture when infiltrated by organic
solvents. Photoactive liquid monomers were infiltrated into extracted silica monoliths and polymerized in situ,
demonstrating the possible application of templated silica to optical storage technology.
Introduction
Photopolymer composites typically consist of a photoactive
component held within the interstitial volumes and channels of
a matrix.1 A two-photon process, combining a modulated signal
beam with a reference beam within a photopolymer composite,

  

Source: Aksay, Ilhan A. - Department of Chemical Engineering, Princeton University

 

Collections: Materials Science