Thin Films of Bicontinuous Cubic Mesostructured Silica Templated by a Nonionic Surfactant

Hayward, Ryan C.; Alberius, Peter; Krämer, Edward J.; Chmelka, Bradley F.

doi:10.1021/la030442z

Cited by 56 publications

(67 citation statements)

References 79 publications

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“…Additionally, a well ordered mesoporous structure was previously reported for Brij78 blends using a slightly lower PHOSt concentration and an organic acid catalyst; the d-spacing for these materials is consistent with the 4.7 nm spacing determined from diffraction [50]. One difficulty with the Brij family of surfactants is the batch to batch variability as was noted by Hayward et al [53]. Therefore, we suspect that different structures may be found depending upon the exact composition.…”

Section: Impact Of Copolymer Chemistrysupporting

confidence: 88%

Templating multiple length scales by combining phase separation, self-assembly and photopatterning in porous films

Song¹,

Wu²,

Vogt³

2008

Journal of Colloid and Interface Science

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Section: Impact Of Copolymer Chemistrysupporting

confidence: 88%

Templating multiple length scales by combining phase separation, self-assembly and photopatterning in porous films

Song¹,

Wu²,

Vogt³

2008

Journal of Colloid and Interface Science

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“…Ordered mesoporous silica films with various unique structures, including lamellar, 2D hexagonal p6mm (thermal-induced to rectangular c2mm), 3 3D hexagonal p6 3 =mmc, 3 bicontinuous cubic Ia3d, 4 primitive cubic Pm3n, 3 orthorhombic Fmmm, 2 tetragonal I4=mmm, 5 rhombohedral R3m, 6,7 have been synthesized using the technique of evaporation-induced self assembly (EISA). 8 Typically, the films are prepared by dip-or spin-coating with an acidic solution of a templating agent such as cetyltrimethylammonium bromide (CTAB) or block copolymer, a silica precursor such as tetraethyl orthosilicate (TEOS), and a water-miscible, volatile solvent (e.g., ethanol).…”

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confidence: 99%

Mesophase Control of Mesoporous Silica Thin Films by Vapor-phase Preparation

Tanaka¹,

Hillhouse²

2006

Chemistry Letters

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Highly ordered mesoporous silica thin films with c2mm rectangular and R3m rhombohedral symmetry have been synthesized on a silicon substrate by a vapor-phase method using PEO 106 -PPO 70 -PEO 106 triblock copolymer as a templating agent.Surfactant-templated mesoporous silica has attracted much attention because of their prospects for microelectronic low dielectric constant 1 Typically, the films are prepared by dip-or spin-coating with an acidic solution of a templating agent such as cetyltrimethylammonium bromide (CTAB) or block copolymer, a silica precursor such as tetraethyl orthosilicate (TEOS), and a water-miscible, volatile solvent (e.g., ethanol). Upon rapid solvent evaporation, at a certain concentration cooperative self-assembly of the surfactant/silicate leads to mesostructures.On the contrary, the vapor-phase synthesis reported by Nishiyama and co-workers 9 performed contacting the template films with hydrolyzed TEOS vapor at 90-120 C to prepare the mesostructured silica films. The TEOS molecules infiltrate into the surfactant film and the TEOS/surfactant composites dynamically rearrange, resulting in the highly ordered mesophase. However, no preparation procedure has been reported to control the mesostructure of the films using the same templating agent.In the present study, we have applied the vapor-phase preparation to the control of mesophase topology and obtained the silica films with c2mm and R3m symmetry using PEO 106 -PPO 70 -PEO 106 (Pluronic F127) copolymer. The phase topology, order, and orientation of the films have identified by the combination of grazing angle of incidence small-angle X-ray scattering (GISAXS) and high-resolution field emission scanning electron microscope (FESEM) measurements. The measured scattering patterns were simulated using NANOCELL, 10 a Mathematicabased program using the distorted wave Born approximation. The predicted spot patterns from NANOCELL are directly overlaid on the GISAXS patterns. The detailed synthesis and characterization methods are shown in the references and notes section. 11The two types of periodically organized mesoporous silica films (MSF) prepared were named accordingly with the TEOS infiltration temperature and time. Hence, the silica films prepared at 90 C for 1 h are labeled MSF90(1).GISAXS and FESEM data for the MSF90(1) shown in Figures 1a-1d are described by rhombohedral R3m structure with the (111) oriented perpendicular to the substrate. The overlay of simulated spots is from a NANOCELL simulation with lattice constants a ¼ 16:9 nm and ¼ 68 . More recently, Tate and co-workers 6 and Naik et al. 7 have reported R3m structured silica films using PEO 20 -PPO 70 -PEO 20 (Pluronic P123) or CTAB in the presence of 1,3,5-triisopropylbenzene, respectively. To the best of our knowledge, there is no literature on the formation of the R3m mesophase using Pluronic F127. Those films have 3D open pore systems providing high pore accessibility from the surface of the films. Although topologically the MSF90(1) is identical to those reported by Tat...

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“…aging temperature of 45°C), the formation of films with this mesostructure was described in the literature. [22] In contrast, films that were prepared under the same conditions with unmodified Brij-56 did not result in the formation of an orthorhombic mesostructure. The obtained films were disordered (M Ͻ 0.05), 2D-centered rectangular (0.05 Ͻ M Ͻ 0.21) and lamellar (0.21 Ͻ M Ͻ 0.42).…”

Section: Resultsmentioning

confidence: 98%