Two-dimensional molecular clusters of a few tens nanometer size were found in spread monolayers of a series of partially fluorinated long-chain acids. Atomic force microscopy images have revealed that the size of the clusters is sharply monodisperse. The size changes systematically with changing structure of the hydrophobic chain of the amphiphiles. The smallest cluster has a circular shape of 17 nm diameter. One cluster is composed of about 700 film molecules. These clusters gather to form macroscopic domains of millimeter size without compression. A formation mechanism of these molecular clusters is discussed. Clusters are formed during the spreading process due to the instability of the film materials at the spreading process. It was made clear that cluster formation during the spreading is rather general for amphiphiles under the conditions where condensed monolayers are formed.

A concept is shown to fabricate mesoporous ceria thin films with a crystalline framework and a bimodal pore size distribution by evaporation-induced self-assembly followed by a suitable temperature treatment and template removal strategy. The use of a suitable block copolymer ((CH 2 CH 2 CH 2 (CH)CH 2 CH 3 ) 79 (OCH 2 -CH 2 ) 89 OH), "KLE") and an ionic liquid template (leading to pores 3 nm in diameter) generated a bimodal pore system of deformed spherical mesopores of ca. 6 nm × 16 nm with the smaller pores being located in the matrix between the larger ones. The porosity was studied by a combination of quantitative SAXS analysis, physisorption, AFM, and TEM, introducing a general methodology for a quantitative structural characterization of such films.

Crack‐free, mesoporous SnO2 films with highly crystalline pore walls are obtained by evaporation‐induced self‐assembly using a novel amphiphilic block‐copolymer template (“KLE” type, poly(ethylene‐co‐butylene)‐block‐poly(ethylene oxide)), which leads to well‐defined arrays of contracted spherical mesopores by suitable heat‐treatment procedures. Because of the improved templating properties of these polymers, a facile heat‐treatment procedure can be applied whilst keeping the mesoscopic order intact up to 600–650 °C. The formation mechanism and the mesostructural evolution are investigated by various state‐of‐the‐art techniques, particularly by a specially constructed 2D small‐angle X‐ray scattering setup. It is found that the main benefit from the polymers is the formation of an ordered mesostructure under the drastic conditions of using molecular Sn precursors (SnCl4), taking advantage of the large segregation strength of these amphiphiles. Furthermore, it is found that the crystallization mechanism is different from other mesostructured metal oxides such as TiO2. In the case of SnO2, a significant degree of crystallization (induced by heat treatment) already starts at quite low temperatures, 250–300 °C. Therefore, this study provides a better understanding of the general parameters governing the preparation of mesoporous metal oxides films with crystalline pore walls.

Micro-phase separation in binary mixed Langmuir monolayers of cadmium salts of n-alkyl fatty acids (CH3(CH2)n-2COOH; Cn (n ) 18, 20, 22, 24)) and a perfluoropolyether surfactant (F(CF(CF3)CH2O)3CF-(CF3)COOH, PFPE) is studied by film balance measurement and atomic force microscopy (AFM). At different temperatures, mixtures of Cn/PFPE in chloroform were spread onto the aqueous Cd 2+ subphase and deposited on silicon wafers. AFM images showed that Cn and PFPE separate into microscopic domains of condensed phase and a surrounding matrix of expanded phase, respectively, in their mixed monolayers. The morphological feature of phase-separated structures was characterized by characteristic length (λ) expressing the periodicity of two-phase distribution and fractal dimension (D) of Cn domains reflecting the complexity of domain shape, which were determined through AFM image analyses. It was found that the monolayer morphologies systematically vary with alkyl chain length of Cn and temperature of the water surface; circular-shaped condensed phase microdomains with D of about 1.1 are formed at λ of 7-9 µm when the mixed monolayers are prepared using a shorter alkyl chain fatty acid and/or at a higher temperature, whereas branched narrow domains with D close to 2 are formed at λ of approximately 4 µm when a longer chain fatty acid is used at a lower temperature.

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Mesoporous thin films of crystalline hafnium oxide were fabricated by evaporation-induced self-assembly in combination with sol-gel processing, followed by a suitable post heat-treatment procedure to initiate the crystallization. A novel type of block-copolymer template was used as structure-directing agent, which generated a distorted cubic arrangement of spherical mesopores, the size of which could be quantified by suitable techniques, such as ellipsometry-porosimetry, small-angle X-ray scattering, and atomic force microscopy. Detailed insights into the nature of the crystallization process of mesostructured hafnium oxide were obtained by temperature-dependent, in situ X-ray scattering experiments. These investigations revealed that crystallization takes place, within the confinement of the mesostructure, as a solid-solid transition from a dehydrated, amorphous form of hafnium oxide. The study suggests that one main benefit of the novel template results from the ability of the polymer to stabilize the mesostructure of amorphous hafnium oxide up to 400-450 degrees C.

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Monolayers of cis-unsaturated fatty acids have been investigated at the air/water interface by using surface pressure (π)−molecular area (A) isotherms and Brewster angle microscopic (BAM) observation. The film materials used are oleic, gondoic, erucic, and nervonic acid. Elaidic acid, a trans-isomer of the oleic acid, is also employed for comparison. The measurements have been performed in a wide temperature range. Oleic and gondoic acid always take expanded phases on the water surface even at near 0 °C. However, first-order phase transitions from expanded to condensed phases have been observed for erucic and nervonic monolayers in certain temperature ranges, accompanied by nonequilibrium growth of condensed phase domains in homogeneous fluid phases. The shape of the emerging domains in the erucic acid monolayers is sixfold and highly dendritic, like snowflakes. The nervonic acid forms also sixfold but rather rounded, flowerlike domains on the water surface. In contrast to the nonequilibrium patterns observed for the cis-unsaturated fatty acid monolayers, elaidic acid monolayers exhibit growth of circular domains in phase transition regions during compression. Formation of the branched structures is interpreted as a consequence of higher supersaturation arising from the packing directivity of cis-long chain into two-dimensional crystal aggregates. For erucic acid monolayers, the shape relaxation of dendrites after compression is stopped is followed by BAM, where the highly branched nonequilibrium structures gradually transform into nearly rounded equilibrium domains with elapsed time.