Silica inverse opal

Scientists also have learned how to mimic the surface of a butterfly wing. Polystyrene beads and smaller silica nanoparticles are suspended in water and mixed thoroughly using ultrasound. When a glass slide is dipped into the suspension and slowly withdrawn, a thin film forms on the glass surface. This film is a regular array of beads encased in a matrix of nanoparticles. Heating the film destroys the polystyrene beads but leaves the silica web intact. The result is a silica inverse opal film. 

Fig. 16a,b. Scanning electron micrographs of gold-silica inverse opals formed by infiltrating colloidal crystals made of polystyrene spheres (diameter 640 nm) with Au Si02 nanoparticles (core 15 nm shell 28 nm). Arrows show point defects within the crystalline structure... 

Jonas and coworkers deposited gold nanoparticles on silane-functionalized silica inverse opals prepared by the codeposition procedure. The gold/sihca hybrid inverse opals shown in Fig. 3a were then formed within the macrop-orous silica network by electroless deposition of HAuCU with hydroxylamine hydrochloride [35]. 

Fig. 13 SEM image of gold nanoparticles (d = 20 nm) deposited on the walls of a silica inverse opal. Scale bar 1 p,m [35]...

D. Wang, V. Salgueiriiio-Maceira, L.M. Liz-Maizan, and F. Caniso, Gold-silica inverse opals by colloidal crystal templating, Adv. Mater. 14,908-912 (2002). 

Similar mirrorless laser-like emission was observed for silica inverse opals infiltrated with rhodamine 6G [105]. Figure 30.15 shows the latex opal obtained... 

Figure 30.15 Scanning electron microscopy images of (a) latex opal and (b) silica inverse opal. (Adapted with permission from Ref. [103].)...

Alencar, M.A.R.C., Madel, G.S., de Araujo, C.B., Bertholdo, R., Messaddeq, Y., and Ribeiro, S.J.L. (2005) Laserlike emission from silica inverse opals infiltrated with Rhodamine 6G. /. Non-Cryst Solids, 351,1846-1849. 

The porous membrane templates described above do exhibit three-dimensionality, but with limited interconnectedness between the discrete tubelike structures. Porous structures with more integrated pore—solid architectures can be designed using templates assembled from discrete solid objects or su-pramolecular structures. One class of such structures are three-dimensionally ordered macroporous (or 3-DOM) solids, which are a class of inverse opal structures. The design of 3-DOM structures is based on the initial formation of a colloidal crystal composed of monodisperse polymer or silica spheres assembled in a close-packed arrangement. The interconnected void spaces of the template, 26 vol % for a face-centered-cubic array, are subsequently infiltrated with the desired material. 

Ordered macroporous materials (OMMs) are a new family of porous materials that can be synthesized by using colloidal microspheies as the template. - The most unique characteristics of OMMs are their uniformly sized macropores arranged at micrometer length scale in three dimensions. Colloidal microspheres (latex polymer or silica) can self assemble into ordered arrays (synthetic opals) with a three-dimensional crystalline structure. The interstices in the colloidal crystals are infiltrated with a precursor material such as metal alkoxide. Upon removal of the template, a skeleton of the infiltrated material with a three-dimensionally ordered macroporous structure (inverse opals) is obtained. Because of the 30 periodicity of the materials, these structures have been extensively studied for photonic applications. In this paper, the synthesis and characterization of highly ordered macroporous materials with various compositions and functionalities (silica, organosilica, titana, titanosilicate, alumina) are presented. The application potential of OMMS in adsorption/separation is analyzed and discussed. 

Although many (perhaps most) applications do not require the existence of a complete band gap, significant efforts to develop such structures have been undertaken. For a given symmetry, the characteristics of an induced band gap depend upon the refractive index contrast and filling factor of the two phases (e.g., silica spheres and air interstices). Inverse opals are negative replicates of the sterically packed structures that have been described above. In this case, one generally has... 

Xu, T., Cheng, Z., Zhang, Q. et al.. Fabrication and characterization of three-dimensional periodic ferroelectric polymer-silica opal composites and inverse opals, J. Appl. Phys., 88, 405, 2000. 

A plasmonic response of the gold/silica composite inverse opals was observed (Fig. 3b), which showed a pronounced spectral change upon the variation of the surrounding dielectric medium by addition of glycerol to the water phase. This property suggests an application of the hierarchically structured replica in the field of optical sensors. 

Fig. 8 Left scheme of vertical lifting codeposition of trimodal colloidal particles. Center trimodal colloidal crystal (tCC) consisting of large PS, intermediate PMMA, and small silica particles. Right Top view of binary inverse opal (blO) after PS and PMMA pyrolysis of the tCC in the center [25]...

The concept of the dual templating method was further extended by Zhou et al. [131], who introduced amphiphilic ionic liquids (AILs) as structuredirecting agents. The use of l-hexadecyl-3-methylimidazolium chloride as AIL provides the following advantages. It structures the silica walls around the macropores of the inverse opal in a highly ordered, microporous lamellar fashion. The interlayer periodicity of the lamellae is about 2.7 nm, with ca. 

Zhou Y, Antonietti M (2003) A novel tailored bimodal porous silica with well-defined inverse opal microstructure and super-microporous lamellar nanostructure. Chem Commun p 2564... 

The synthesis of macroporous carbon materials was first realised by Zakhidov et al. in 1998. Macroporous carbon materials with inverse opal structures, as shown in Figure 4.14, were obtained using silica opals as hard templates and phenol resin and/or propylene gas as carbon precursor. The macroporous carbons had different structures depending... 

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