A facile route to synthesize mesoporous ZSM-5 with hexagonal arrays using P123 triblock copolymer

Porins represent a group of channel forming proteins that facilitate diffusion of small solutes across the outer membrane of Gram-negative bacteria, while excluding large molecules (>650 Da). Planar membranes reconstituted from purified matrix porin (OmpF protein) trimers and phospholipids have allowed quantitative functional studies of the voltage-dependent channels and revealed concerted activation of triplets. Under the same reconstitution conditions but using high protein concentrations porin aggregated to 2D lattices suitable for electron microscopy and image processing. Depending on the lipid-to- protein ratio three different crystal packing arrangements were observed: a large (a = 93 Å) and a small (a = 79 Å) hexagonal and a rectangular (a = 79 Å b = 139 Å) form with p3 symmetry for the hexagonal arrays. In all crystal forms distinct stain filled triplet indentations could be seen and were found to be morphologically identical within a resolution of (22 Å). It is tempting to correlate stain triplets with triple channels, but the proof of this hypothesis requires an analysis of the structure in 3 dimensions.

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Observations on the Structure of Ta2O5

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100095959 ◽

1972 ◽

Vol 30 ◽

pp. 540-541

Author(s):

P. S. Kotval ◽

C. J. Dewit

Keyword(s):

Electron Microscope ◽

Structural Features ◽

Amorphous Structure ◽

Polished Surface ◽

Distilled Water ◽

Anodic Films ◽

Amorphous Films ◽

Beam Heating ◽

Diffraction Patterns ◽

Hexagonal Arrays

The structure of Ta2O5 has been described in the literature in several different crystallographic forms with varying unit cell lattice parameters. Earlier studies on films of Ta2O5 produced by anodization of tantalum have revealed structural features which are not consistent with the parameters of “bulk” Ta2O5 crystalsFilms of Ta2O5 were prepared by anodizing a well-polished surface of pure tantalum sheet. The anodic films were floated off in distilled water, collected on grids, dried and directly examined in the electron microscope. In all cases the films were found to exhibit diffraction patterns representative of an amorphous structure. Using beam heating in the electron microscope, recrystallization of the amorphous films can be accomplished as shown in Fig. 1. As suggested by earlier work, the recrystallized regions exhibit diffraction patterns which consist of hexagonal arrays of main spots together with subsidiary rows of super lattice spots which develop as recrystallization progresses (Figs. 2a and b).

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Morphological transformations in solution-cast Styrene-Butadiene-Styrene (SBS) triblock copolymer thin films

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010013729x ◽

1995 ◽

Vol 53 ◽

pp. 184-185

Author(s):

Ginam Kim ◽

W. Marsillo ◽

M. Libera

Keyword(s):

Thin Films ◽

Triblock Copolymer ◽

Annealing Treatment ◽

Minor Component ◽

Solvent Evaporation ◽

Single Crystal Substrate ◽

Transparent Films ◽

Crystal Substrate ◽

Solution Cast ◽

Morphological Transformations

The fact that block copolymers can assume a range of morphologies depending upon such variables as relative block length and molecular weight is now well known. In the case of poly(styrene)[PS]-poly(butadiene)[PB]-poly(styrene) (SBS) triblock copolymer, the morphologies range from spheres (roughly ~20% minor component), to cylinders (roughly 20%~35% minor component), to lamellae (roughly equal component fractions) Most recently, there has been increasing interest in transformations between morphologies by thermal annealing. This paper describes initial results studying the effect of solvent evaporation rate and post-casting annealing treatment on the morphology of SBS thin films.TEM specimens were prepared by solution casting electron transparent films. 50 μl of 0.1 wt% SBS (30% styrene, Mw=14,000, Scientific Polymer Products, Inc.) dissolved in toluene was deposited on a polished NaCl single crystal substrate placed in a small dish. After solvent evaporation the film was cut into small squares, floated from the salt in water, and each square was collected on a Cu grid.

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A new and facile route from a thiaphane to a cyclophane via iron pentacarbonyl

Journal of Organometallic Chemistry ◽

10.1016/s0022-328x(00)98868-5 ◽

1983 ◽

Vol 243 (1) ◽

pp. 191-193 ◽

Cited By ~ 4

Author(s):

A Koray

Keyword(s):

Iron Pentacarbonyl ◽

Facile Route

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Size Control of Block Polymer Templated Mesoporous Silicate Materials

MRS Proceedings ◽

10.1557/proc-628-cc6.24 ◽

2000 ◽

Vol 628 ◽

Author(s):

Takeo Yamada ◽

Keisuke Asai ◽

Kenkichi Ishigure ◽

Akira Endo ◽

Hao S. Zhou ◽

...

Keyword(s):

Mesoporous Materials ◽

Molecular Sieve ◽

Mesoporous Material ◽

Triblock Copolymer ◽

Size Control ◽

Block Polymer ◽

New Class ◽

Mesoporous Silicate ◽

Cubic Structure ◽

Silicate Materials

ABSTRACTMesoporous materials have attracted considerable interest because of applications in molecular sieve, catalyst, and adsorbent. It will be useful for new functional device if functional molecules can be incorporated into the pore of mesoporous material. However, it is necessary to synthesize new mesoporous materials with controlled large pore size. Recently, new class of mesoporous materials has been prepared using triblock copolymer as a template. In this paper, we reported that hexagonal and cubic structure silicate mesoporous materials can be synthesized through triblock copolymer templating, and their size was controlled by synthesis condition at condensation.

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