T. M. Putvinski

Polar orientation of dyes in robust multilayers by zirconium phosphate-phosphonate interlayers.

Polar orientation of molecules in solids leads to materials with potentially useful properties such as nonlinear optical and electrooptical activity, electrochromism, and pyroelectricity. A simple self-assembly procedure for preparing such materials is introduced that yields multiple polar dye monolayers on solid surfaces joined by zirconium phosphate-phosphonate interlayers. Second harmonic generation (SHG) shows that the multilayers have polar order that does not decrease with increasing numbers (up to a large number) of monolayers in the film. The inorganic interlayers, as determined by SHG, impart excellent orientational stability to the dye molecules, with the onset of orientational randomization above 150�C.

Self-assembly: its use in at-the-surface imaging schemes for microstructure fabrication in resist films

Abstract The self-assembly of refractory films on organic resist surfaces is used to provide an etching mask during the plasma transfer of patterns through underlying organic resists. Multilayer self-assembly using ZrOCl2 and H4P2O7 reagents affords multilayer structures that are selectively bound to oxidized resist layers. Imaging is achieved using phenolic resin materials that are exposed to 193 nm radiation.

Electrical and nonlinear optical properties of zirconium phosphonate multilayer assemblies

Multilayer assembly of organic chromophores with inorganic interlayers is a facile technique for the preparation of nonlinear optical materials with well-defined architectures. Recent reports of T. M. Mallouk (University of Texas-Austin) have indicated that zirconium organodiphosphonates form particularly stable surface multilayers that can be constructed straightforwardly one monolayer at a time. We have synthesized a series of chromophores with shapes and functional groups designed for layerwise deposition as zirconium phosphonates. These include electron donating thiophene oligomers, electron accepting quinodimethanes, and dipolar azo dyes. Cohesive, electrically insulating, thermally stable films of these compounds as layered phosphonates on various substrates were prepared with predictable thicknesses and, in some cases, polar order. Second harmonic intensity from the polar azo dye films was proportional to the thickness squared, consistent with theory. The dielectric and optical responses of a variety of other kinds of samples are discussed.