DE102010014236A1 - Method for coating substrate surface of e.g. cable, with non-metallic character in arts and crafts, involves forming stable nanoparticle layer on surface, and removing non-binding naoparticle by washing with solvent - Google Patents

Abstract

The method involves dispersing a nanoparticle in solvent, and stabilizing colloidal nanoparticle with polymer. A substrate surface to be coated is moistened with stabilized nanoparticle solution. Polymer chains are fixed at the surface, so that a substrate-nanoparticle binding is formed. A stable nanoparticle layer is formed on the surface by collapsing and aggregating a colloidal system. A non-binding nanoparticle is removed by washing with the solvent after completion of a coating process. (Incomplete specification, abstract based on available information published by the patent office).

Description

The invention relates to a surface modification system for the coating of substrate surfaces with non-metallic character, wherein a dispersion of partially polymer-protected nanoparticles is used. The interaction between nanoparticles, substrate surface and polymer chains results in an adhesion promoter layer to which further metallic layers can be attached.

State of the art

The application of metallic layers on surfaces is z. B. performed in the arts and crafts. Here is the surface gilding for bonding the so-called apply oil ( Bachmann et al. Chemistry in our time 23 1989 46 ) used. This consists predominantly of waxy polyunsaturated monocarboxylic acids.

For the metallization of non-conductive surfaces various methods are used. For example, analytics often involves covering with electrically conductive layers (gold sputtering)

For controlled growth of metal nanoparticle layers, other vacuum techniques such as physical vapor deposition (PVD) are used.

In the Bellouet et al. submitted document US6743345 a flexible substrate is metallized. For this purpose, an immobilized precursor is activated by means of laser energy and subsequently reacted with metal salts to be reduced.

The use of nanoparticle dispersions / pastes for the metallization of non-electrically conductive porous substrates is well known. For example, describes Kowalik et al. (Macromol Symp 354 2007 300) the use of 60-80m% Ag pastes to visualize conductive structures on paper.

Gold leaf coating is characterized by a good adhesion. However, when mechanical forces are applied, delamination is detected. Moreover, it is of economic interest to be able to reduce labor time while increasing coating stability.

A disadvantage of sputtering and other vacuum techniques is the high energy consumption, the applicability to predominantly flat substrates and the low adhesion or breakage stability.

The object of the present invention is to bond conductive layers in combination with adhesion-promoting character to surfaces of non-metallic character. Due to the chemical and physical nature of non-metallic surfaces, the wetting and adhesion by adhesion promoters and thus the homogeneous and stable metal coating is problematic. In addition, the environmental and health protection is a challenge.

The object is achieved by a method according to the main claim. Advantageous embodiments are given in the appended claims.

The basic idea relates to the metallization of non-metallic substrates, wherein a more or less adhesion-promoting layer of collapsed nanoparticles constitutes an electrically conductive base for further metal layers.

According to the invention, the object is achieved by a method for coating a substrate surface with a non-metallic character by means of nanoparticles. First, the nanoparticles are dispersed in a solvent. Subsequently, the stabilization of the colloidal nanoparticles with a polymer and / or other additives / surfactants. Thereafter, the substrate surface to be coated is wetted with the stabilized nanoparticle solution, wherein a fixation of the polymer chains takes place on the substrate surface, by physical and / or chemical interaction. In such a way, a substrate nanoparticle bond is formed. By collapsing and aggregating the colloidal system, a stable nanoparticle layer is formed on the substrate surface. In a subsequent step, after completion of the coating process, the unbonded nanoparticles are removed by washing with a solvent. For additional system stabilization, crosslinking steps known to the person skilled in the art can be carried out.

Swelling of the substrate surface may be helpful, especially with regard to interpenetrating networks (IPN). The surface system can be stabilized by further crosslinking steps. If a swelling is not possible for substrate-specific reasons, the adhesion mediation can be mediated by adsorption. These can be reinforced by a certain pore structure of the substrate.

Other metal layers can be applied to the layer of collapsed nanoparticles by a variety of methods. The nanoparticles serve as interaction centers for the subsequent coating. The final step is the drying of the coated substrate surface.

For the purposes of the invention, a substrate surface with a non-metallic character is understood to mean a non-electrically conductive surface. The substrate surface may be part of a non-metallic article of various geometries (eg cable, plate, rod, tube, sphere, tissue, stent-like constructs), a porous substrate, a fiber composite material or the like. The substrate may have a flat or structured surface, which favors the adhesion of the surface modification system. The substrate surface may comprise one or more elements selected from groups 1 to 16 and the lanthanides of the Periodic Table of the Elements, oxides thereof, as well as mixtures, alloys, etc.

In a further embodiment of the invention, the adhesion promoter layer is stabilized by initiating crosslinking steps. For this purpose, crosslinking agents and polymerization initiators can be added to the adhesion promoter system.

The invention will be explained in more detail with reference to some embodiments. Show in:

Embodiment 1

Surface gilding - adhesion

A wood body is impregnated with a polymer-stabilizing metal (nano) particle dispersion, wherein the dispersion can also be mechanically incorporated into the substrate. Swelling of the substrate can cause entanglements between the cellulose chains and the particle-stabilizing polymer chains. Subsequently, a drying step is performed. An additional crosslinking reaction can stabilize the surface system. The immobilized metal (nano) particles can now be used as the first layer for further metallization, eg. As gold occupancy can be used. For this purpose are z. B. Brush processes with thin layers of gold leaf are applied to the substrate.

Embodiment 2:

II. Production of Hybrid Electrodes

A more or less porous glass substrate is immersed in a polymer-stabilized metal (nano) particle dispersion. During heating to about 180 ° C for 1 h, the particles attach to the substrate. Subsequently, a drying step is performed. For further stabilization of the surface system, a sintering step can be carried out. The resulting surface is electrically conductive and can now be further metallized. For this purpose, particularly galvanic processes are suitable.

A downstream sintering step can result in an abrasion-stable glass-metal hybrid system. Such a sintering step can be carried out in vacuum or a special atmosphere at temperatures of 100 ° C upwards.

In a further embodiment, the surface modifications according to the invention constitute the basis for electrodes having an increased surface roughness. By the targeted growth of palladium islands, electrodes of improved catalytic activity can be produced.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 6743345 [0005]

Cited non-patent literature

• Bachmann et al. Chemistry in our time 23 1989 46 [0002]
• Kowalik et al. (Macromol Symp 354 2007 300) [0006]

Claims (1)

No claims have been filed.