Sigma Laboratories of Arizona, Inc.

Gordon Goodyear

Angelo Yializis

Vladimir Gordyienko

Marlowe Engquist

A high surface area valve-metal capacitor electrode is formed on a moving substrate in vacuum by a continuous multilayer vapor-phase deposition process under conditions of substrate temperature and speed that produce continuously growing, uninterrupted dendritic structures. The process is carried out in an atmosphere of inert gas, preferably including He or Ar, with or without an impurity gas such as oxygen. The substrate may be a valve-metal foil or wire, a metal screen, a polymer film, an organic or inorganic fiber, or a composite material. The direction of motion of the moving substrate may be reversed during the deposition process in order to increase the porosity of the dendrites. The electrode may be passivated using an oxygen-containing plasma before exposure to air. The process may also be carried out under conditions that produce boundary-layer turbulence in order to promote the continuously growth of uninterrupted dendritic structures.

High-Surface Capacitor Electrode

Functionalized multilayer structures are manufactured by a process whereby a substrate material is treated with a reactive-gas plasma to form an activated layer on the surface thereof, and then by depositing a liquid functional monomer on the activated layer to form a self-assembled functional layer. Any excess liquid monomer must be allowed to re-evaporate in order to obtain optimal functionality on the surface of the resulting structure. The deposition of the liquid layer is preferably carried out with high kinetic energy to ensure complete penetration of the monomer throughout the body of the substrate. For particular applications, prior to formation of the reactive layer the substrate may be coated with a high glass-transition temperature polymer or a metallic layer.

Self-assembled functional layers in multilayer structures

Polymer-based optically-variable devices (OVDs) for security applications and methods for producing the same. The uniformity of thickness of the structure of such devices is optimized by controlling previously neglected process parameters such as the temperature distribution of the deposition nozzle, the substrate and the deposition drum, their emissivities, the micro-roughness of the substrate, and the rate of monomer re-evaporation. Re-evaporation is minimized by initiating radiation-curing within two seconds of monomer deposition. A method includes equipment reducing all sources of emissivity non-homogeneities, such as surface blemishes in the surface areas exposed to the substrate to preferentially fabricate substrates with haziness less than 5% and gloss greater than 90%. Controlling, a maximum variation of thickness of the transmissive layer of an OVD ensures that no appreciable color-shift variation is visible to the naked eye.

Methods for fabrication of polymer-based optically variable devices

A multilayer dielectric structure is formed by vacuum depositing two-dimensional matrices of nanoparticles embedded in polymer dielectric layers that are thicker than the effective diameter of the nanoparticles, so as to produce a void-free, structured, three-dimensional lattice of nanoparticles in a polymeric dielectric material. As a result of the continuous, repeated, and controlled deposition process, each two-dimensional matrix of nanoparticles consists of a layer of uniformly distributed particles embedded in polymer and separated from adjacent matrix layers by continuous polymer dielectric layers, thus forming a precise three-dimensional nanoparticle matrix defined by the size and density of the nanoparticles in each matrix layer and by the thickness of the polymer layers between them. The resulting structured nanodielectric exhibits very high values of dielectric constant as well as high dielectric strength.

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Tucson, AZ, United States of America

Gordon Goodyear