Conductive Polymer Coatings via Oxidative CVD

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Solution Overview

Problem

Conductive polymer coatings formed by conventional methods often exhibit inhomogeneous properties due to poor surface wetting, leading to non-uniform properties and performance issues in applications such as EMI shielding and electronic devices.

Innovation Solution

The method involves contacting a surface with a gaseous metal-containing oxidant and a gaseous polymerizable species, either in sequence or simultaneously, to form a conductive polymer coating, which can include metallic particles to enhance conductivity and shielding effectiveness, using oxidative chemical vapor deposition techniques that avoid liquid wetting issues and allow for tunable properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If liquid polymer solution is deposited by spray-, dip- or spin-coating techniques, then conductive polymer coatings can be formed, but the coatings become inhomogeneous due to poor solution wetting of the surface

Engineering Contradiction:
Improvecoating uniformityVSAvoidsurface wetting
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent changes the physical state of the polymer solution from liquid to vapor phase. By using chemical vapor deposition, the polymer is deposited as a vapor that condenses and polymerizes on the substrate surface, eliminating the wetting issues associated with liquid coatings and achieving uniform, homogeneous coatings regardless of surface energy characteristics.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention utilizes phase transition by depositing the polymer in vapor phase rather than liquid phase. The vaporized polymer monomers or oligomers condense on the cooled substrate surface and undergo polymerization, forming uniform coatings without the wetting problems inherent in liquid deposition methods.

Inventive Principle:
Principle #36Phase transitions

2Quantity of substance

If conventional liquid coating methods are used, then conductive polymer coatings can be applied to surfaces, but the coatings exhibit non-uniform properties

Engineering Contradiction:
Improvepolymer depositionVSAvoidcoating homogeneity
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent replaces the mechanical liquid deposition process (spray, dip, or spin coating) with a vapor-phase chemical deposition process. This substitution eliminates the mechanical wetting and flow issues that cause non-uniformity, allowing for precise control of polymer deposition and homogeneous coating formation through vapor condensation and polymerization on the substrate surface.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If conductive polymer coatings are formed with poor surface wetting, then coating formation is achieved, but the coatings have non-uniform properties affecting performance

Engineering Contradiction:
Improvecoating formationVSAvoidcoating uniformity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The invention changes the deposition parameters by transitioning from liquid-phase to vapor-phase polymer deposition. This parameter change fundamentally alters the coating formation mechanism, allowing easy coating application through vapor condensation while simultaneously achieving uniform properties, thus resolving the contradiction between ease of manufacture and coating uniformity.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach results in homogeneous, conformal conductive polymer coatings with improved electrical conductivity and EMI shielding performance, capable of meeting military standards across the full EMI spectrum while minimizing weight and maintaining substrate geometry.

Implementation Method 1

contacting said oxidant-enriched surface with a gaseous polymerizable species thereby forming a conductive polymer coating on the surface

Methodology Applied
Scientific EffectOxidative polymerization: Oxidation

Implementation Method 2

contacting said surface with a gaseous polymerizable species thereby forming a polymerizable species-enriched surface

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 3

using oxidative chemical vapor deposition techniques that avoid liquid wetting issues

Methodology Applied
Scientific EffectChemical vapor deposition: Chemical Vapour Deposition

Data Source

PatentUS8227025B2Conductive polymer coatings and methods of forming the same
Publication Date: 2012.07.24 GVD CORP

AI summary

Conductive polymer coatings and methods of forming the same are provided.