We have measured the dielectric response of monolayer films of surface mounted chloromethyl-and dichloromethylsilyl dipolar rotors on fused silica at frequencies in the 1 kHz range and temperatures from 4 to 300 K. The torsional potentials, calculated from molecular mechanics, show an asymmetrical threefold barrier to rotation with a barrier height sufficient to hinder motion of the rotor at experimental temperatures. A broad distribution of barrier heights is observed experimentally, consistent with calculated results showing that the intrinsic barrier of the rotor is modified by interactions with the underlying substrate. For a series of samples with differing concentrations of the rotor, the observed signal strength varies in proportion to the rotor coverage measured by Auger spectroscopy; however, the absolute strength of the signal is about three times larger than expected.

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Spatial atomic layer deposition (S-ALD) was examined on flexible porous substrates utilizing a rotating cylinder reactor to perform the S-ALD. S-ALD was first explored on flexible polyethylene terephthalate polymer substrates to obtain S-ALD growth rates on flat surfaces. ZnO ALD with diethylzinc and ozone as the reactants at 50 °C was the model S-ALD system. ZnO S-ALD was then performed on nanoporous flexible anodic aluminum oxide (AAO) films. ZnO S-ALD in porous substrates depends on the pore diameter, pore aspect ratio, and reactant exposure time that define the gas transport. To evaluate these parameters, the Zn coverage profiles in the pores of the AAO films were measured using energy dispersive spectroscopy (EDS). EDS measurements were conducted for different reaction conditions and AAO pore geometries. Substrate speeds and reactant pulse durations were defined by rotating cylinder rates of 10, 100, and 200 revolutions per minute (RPM). AAO pore diameters of 10, 25, 50, and 100 nm were utilized with a pore length of 25 μm. Uniform Zn coverage profiles were obtained at 10 RPM and pore diameters of 100 nm. The Zn coverage was less uniform at higher RPM values and smaller pore diameters. These results indicate that S-ALD into porous substrates is feasible under certain reaction conditions. S-ALD was then performed on porous Li ion battery electrodes to test S-ALD on a technologically important porous substrate. Li0.20Mn0.54Ni0.13Co0.13O2 electrodes on flexible metal foil were coated with Al2O3 using 2–5 Al2O3 ALD cycles. The Al2O3 ALD was performed in the S-ALD reactor at a rotating cylinder rate of 10 RPM using trimethylaluminum and ozone as the reactants at 50 °C. The capacity of the electrodes was then tested versus number of charge–discharge cycles. These measurements revealed that the Al2O3 S-ALD coating on the electrodes enhanced the capacity stability. This S-ALD process could be extended to roll-to-roll operation for the commercialization of S-ALD for coating Li ion battery electrodes.

The adsorption of the trigonal connector, 1,3,5-tris[10-(3-ethylthiopropyl)dimethylsilyl-1,10-dicarba-closo-decaboran-1-yl]benzene (1), from acetonitrile͞0.1 M LiClO 4 on the surface of mercury at potentials ranging from ؉0.3 to ؊1.4 V (vs. aqueous AgͦAgClͦ1 M LiCl) was examined by voltammetry, Langmuir isotherms at controlled potentials, and impedance measurements. No adsorption is observed at potentials more negative than ϳ ؊0.85 V. Physisorption is seen between ϳ ؊0.85 and 0 V. At positive potentials, adsorbate-assisted anodic dissolution of mercury occurs and an organized surface layer is formed. Although the mercury cations are reduced at ؊0.10 V, the surface layer remains metastable to potentials as negative as ؊0.85 V. Its surface areas per molecule and per redox center are compatible with a regular structure with the connectors 1 woven into a hexagonal network by RRS3 Hg 2 2؉ 4SRR or RRS3 Hg 2؉ 4SRR bridges. The structure is simulated closely by geometry optimization in the semiempirical AM1 approximation. E lsewhere in this issue (1) we outline the motivation for our efforts to prepare extended regular grids on the surface of mercury by reversible self-assembly. Here, we describe an electrochemical Langmuir trough for the determination of a surface molecular area at the interface of mercury and an electrolyte solution at a controlled potential. We use it to shed light on the possible formation of a two-dimensional hexagonal grid by the binding of trigonal connectors to each other through a mutual coupling of their thioether-containing arm terminals by means of ligation to mercury cations.It has been long known (2) that anodic dissolution of mercury is facilitated by the presence of species with a large affinity for mercury ions. These can be anions, such as oxalate (3, 4), or neutral ligands, such as azaaromatics (5). Sulfur compounds, especially sulfide and thiols, have attracted particular attention (6-16). Often, the mercury-ion-containing salts adhere firmly to the mercury surface in the form of highly insoluble compact monolayers or multilayers. Although the mechanism of their formation has been much investigated (4,5,10,11,13,(17)(18)(19)(20)(21)(22)(23)(24), structural information for these layers on mercury is limited except for the simplest cases, such as Hg 2 Cl 2 (25, 26). The growth of two-dimensional crystals of salts of other metals on mercury surface is known (27, 28), and nucleation and growth phenomena in electrocrystallization have been reviewed recently (29). The mercury-adsorbed layers are compact, with lateral interactions among the adsorbed species essential for stability.We have reported (30) the formation of such an adsorbed layer on a dropping mercury electrode from acetonitrile and dichloromethane solutions of a trigonal connector with a thioether link in each of its three arms, and suggested an open hexagonal grid structure for it. We now examine in more detail the properties of a monolayer formed from a similar connector that differs only by substitution of 10-vertex for 12-v...