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The synthesis of oxygen-free, phenyl-modified organosilicon nanosheets with atomic thickness is described. Light-induced photocurrent in [[Si.sub.6][H.sub.4][Ph.sub.2]] is observed, which has led to the possibility of various organosilicon nanomaterials with useful properties.

Oxygen-free silicon nanosheets covered with organic groups are obtained by exfoliation of layered polysilane as a result of reaction with n-decylamine and dissolution in an organic solvent. The nanosheets have very flat and smooth surfaces because of dense coverage of n-decylamine and they are self-assembled in a concentrated state to form a regularly stacked structure.

We attempted to evaluate the interaction between metal and polyphenylene sulfide (PPS), and especially metal-sulfur bonding, by using time-of-flight secondary ion mass spectrometry and atomic force microscopy. As model PPS compounds, two kinds of phenylene sulfide oligomer-a tetramer and a heptamer-were synthesized and their monolayers and multilayers were formed on Ag, Cu, and Al substrates. Comparison of the monolayers with the multilayers revealed that, in the case of the tetramer, the monolayers formed uniformly on all substrates and metal-sulfur bonds were present. The Ag-sulfur and Cu-sulfur bonds were stronger than the Al-sulfur bond. In contrast, with the heptamer, the molecular interaction was stronger than that with the substrates, and consequently the sulfur atoms did not contact the metals. Therefore, the monolayers barely formed on all substrates. These results indicated that the larger the oligomer, the weaker the metal-sulfur bonding; this is one of the reasons why it is difficult to join PPS to metal directly. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This study aims to develop a molecular dynamics (MD) simulation procedure to investigate the wettability of primer-treated Al 2 O 3 surfaces by bisphenol A diglycidyl ether (BADGE) and to understand the interaction between the surface and the liquid. The MD simulation results were compared with those obtained by contact angle measurements, time-of-flight secondary ion mass spectrometry (TOF-SIMS), and atomic force microscopy (AFM) and were found to be in agreement with the experimental evaluations. The results obtained from both the MD simulations and the experiments suggest that the configuration of the primers on the surface affect its wettability. In other words, silanes lying flat on the surface, such as mercapto silane, make it easy for BADGE to access any polar functional groups of the silane, thereby leading to a strong interaction and good wettability. For amino silane, although the configuration is similar to that of mercapto silane, its amino groups are bound to the surface owing to their high polarity, which results in a reduced accessibility for BADGE and a relatively poor wettability in comparison with mercapto silane. On the contrary, for silanes that stand up on the surface, including trifluoroalkyl silane, BADGE is hindered from approaching the silanol groups and interacting with them, and the surface shows poor wettability.

We use molecular dynamics (MD) simulations to investigate the wettability of Al 2 O 3 (0001) by organic molecules. Diffusion coefficients estimated for organic molecules are clearly correlated with the contact angles observed experimentally. The results of the MD simulations suggest that molecular flexibility influences wettability. In other words, wettability owing to flexible molecules, such as an epoxy tridecamer, improves with increasing temperature because the interaction between the droplet and the surface increases due to changes in molecular conformation. Conversely, for phenylene sulfide tetramer, wettability does not change with temperature because of the molecular rigidity. In addition, for epoxy monomers, we analyze the different molecular structures responsible for modifying the droplet-surface interaction. For hydrogens in aromatic rings and in methyl groups, the interaction with the surface clearly decreases with increasing temperature.