Wormhole-like structure

Wang Y, Tang X, Lin L, Huang W, Haochen Y, Gedanken A (2000) Sonochemical synthesis of mesoporous titanium oxide with wormhole-like framework structures. Adv Mater 12 1183-1186... 

Y.Q. Wang, X.H. Tang, L.X. Yin, W.P. Huang, Y.R. Hacohen, and A. Gedanken, Sono-chemical Synthesis of Mesoporous Titanium Oxide with Wormhole-like Framework Structures. Adv. Mater, 2000, 12, 1183-1186. 

Membranes synthesized on y- AI2O3 have various morphology (Figs. 1, 3a and 4). The typical results obtained are shown in Table 1 together with synthesis conditions. The materials obtained are amorphous, MFI type zeolite or MSU mesoporous materials with a disordered wormhole like structure, depending on the support pretreatment and synthesis conditions. 

Fig. 1 reports the XRD patterns of materials obtained at 60°C for different treatment durations. At this tenperature, onfy one peak located at 13.0, 11.6 and 16.4 nm for heating times of 2 (Fig.lb), 3 (Fig.lc) and 11 days (Fig.ld) respectively, is detected. The presence of only one reflection line indicates that the compounds belong to the MSU or DWM femily. The structure of these moleeular sieves consists of regularly sized wormhole-like channels. The single broad peak arises from the average pore-to-pore separation in the disordered... 

The TEM picture of one of our typical san jles reported in Fig. 2 confirms the wormhole-like structure of our materials and its adherence to MSU (or DWM) family. If the heating temperature is increased to 80 or 100°C (dififractograms are not reported), no peak is detected any more after 2 days of hydrothermal treatment. This results from the fact that, as will be discussed further, the pore size distributions are very likely to broaden and to become more or less inhomogeneous for the higher tenqjeratures. The regular size of the channels could then be partly lost. It should be noted that for the sample which has not been subjected to a hydrothermal treatment, one reflection located at 7.5 nm (Fig. la) is present on the XRD pattern. So, when tetramethoxysilane is added to the prepared micellar solution and pH is adjusted, the condensation and polymerization... 

Fig. 5 TEM pictures of A a disordered wormhole-like structure, B a regular hexagonal framework and C a fingerprint -like arrangement of channels.

It was observed that the furfuryl alcohol/TEOS ratio significantly affected the mesopore size of resulting carbon. Moriguchi et al. reported the direct synthesis of mesoporous carbon material by in situ polymerisation of divinylbenzene in the hydrophobic phase of a hexagonally arrayed micelle/silicate nanocomposite and its subsequent carbonisation and HE treatment. The resulting carbon material had poor structural ordering with only wormhole-like mesopores of 2 nm. The synthesis of mesoporous carbon via one-step vapour deposition polymerisation using... 

An interesting study is that of Stebe ct al., which described the phase behavior of C8Fi7C2H4(OC2H4) OH/methanol/water systems [59]. Well-ordered liquid crystals can be obtained up to a concentration of methanol in the solution around 8 wt%. If the methanol content in the mixture is further increased, the pore ordering is lost and the recovered materials adopt a wormhole-like structure. 

Recently, a selective etching method has been developed as a simple and effective strategy to fabricate hollow mesoporous silica particles. Fang et al. reported the formation of hollow mesoporous sihca spheres with either a wormhole-like or an oriented pore structure by treatment of sohd silica spheres in a sodium... 

Subsequently, it was found that the surfactant in the synthesis system can modify the mesoporous textural properties but does not affect the self-formation of the meso-macroporous hierarchy. Zirconium oxides with the similar meso-macropo-rous structure could also be synthesized via the self-formation phenomenon in the absence of a surfactant [131]. The resulting hierarchically meso-macroporous zir-coniiun oxides are mainly tens of micrometers in size with a regular array of parallel or funnel-like macrochannek of 300-800 nm in diameter. The macropore walls are constmcted from mesochannels (around 2.0 nm) with a wormhole-like array. These materials obtained via this self-formation phenomenon present high surface area and pure crystalline phases in meso-macroporous structures. 

Note that the term wormhole is used in two different senses in the physics literature. The first kind of wormhole is made of quantum foam. Because of the foam-like structure of space, countless wormholes may connect different parts of space, like little tubes. In fact, the theory of superspace suggests that... 

The exterior of the Visser wormhole acts like a giant mirror. Light shining on it would bounce off as if it hit a reflecting material. Visser also proposed another mathematical model for a wormhole that resembles two coreless apples. The inner walls of the fruit are connected along the fourth dimension. You can read more about this structure in Halpern s Cosmic Wormhole book or in Visser s original scientific paper. 

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