Substrate-induced crystal plastic phase of a discotic liquid crystal.

A new phase of a known discotic liquid crystal is observed at the interface with a rigid substrate. The structure of the substrate-induced phase has been characterized by atomic force microscopy, specular X-ray diffraction, and small-angle and wide-angle grazing incidence X-ray diffraction. The substrate-induced phase, which has a thickness of ∼30 nm and a tetragonal symmetry, differs notably from the bulk phase.

Dimers of anthrathiophene and anthradithiophene derivatives: synthesis and characterization.

Synthesis, isolation, and characterization of derivatives of an anthrathiophene dimer (TOTBAT) and of anthradithiophene oligomers (ADTO), possessing octylthiophene units on their backbone, are described. These semiconductors are prepared through oxidative copper(II) chloride coupling. The spectroscopic properties and stability of these newly synthesized semiconductors were evaluated and supported by quantum-chemical calculations.

Self-assembled monolayers: solidification of carbamazepine in Form II at an interface.

A self-assembled monolayer incorporating well-spaced biphenyl moieties initiates solidification of carbamazepine at its interface. A detailed analysis of the resulting crystals using X-ray powder diffraction, FTIR-ATR as well as thermomicroscopy, indicates a preference for its crystallization in trigonal (Form II) polymorph.

Self-assembled monolayers: influence of complementarity between chemisorbed and crystallizing molecules in polymorph selection.

The role of self-assembled monolayers in dictating the arrangement of molecules at the interface in a developing solid is explored. A self-assembled monolayer incorporating a complementary backbone structure between chemisorbed and crystallizing molecules of 4-hydroxybiphenyl favors its crystallization in a new monoclinic crystal packing arrangement.

Influence of interfacial features in the supramolecular assembly of 3,5-dihydroxybenzylalcohol based dendrimers on Si/SiO2 surfaces.

Self-organization of 3,5-dihydroxybenzylalcohol (DHBA) based dendrimers of generations 0-3 (G0-G3) on bare and functionalized single crystal silicon (Si/SiO2) surfaces has been examined. The underlying monolayer plays a significant role in the supramolecular assembly leading to ordered structures of DHBA (G0) and generation 1-3 (G1-G3) dendrimers at interfaces. Ordered hyperbranched structures are formed on surfaces containing self-assembled monolayers with complimentary features to the assembling molecules, whereas no such organized assemblies are observed on unfunctionalized surfaces.

Templated crystallization of octadecanol on patterned nanoassemblies.

A serial templating methodology using linked aminosilane/stannane units and simple beaker chemistry yields thin film nanoassemblies on semiconductor surfaces that provide nucleating sites for crystallization of octadecanol, the morphologies of which could be tailored using subtle variations in the backbone structure of bridged aminosilane/stannanes.