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US-12624457-B2 - Thermal decomposition metallization process

US12624457B2US 12624457 B2US12624457 B2US 12624457B2US-12624457-B2

Abstract

A method for forming a conductive metal-polymer composite coated polymer includes providing a polymer substrate and immersing the polymer substrate in a metal solution. The method further includes decomposing the metal solution in a thermally controlled environment and reducing the metal solution to metal such that the metal is deposited on a surface of the polymer substrate. After reducing the metal solution, the method includes treating the surface with a polymer coating to form the metal-polymer composite coated polymer.

Inventors

  • Jar-Wha Lee
  • Zachary Douglas Adams
  • Mark Andrew Maltese

Assignees

  • GLENAIR, INC.

Dates

Publication Date
20260512
Application Date
20191127

Claims (16)

  1. 1 . A method for forming a conductive metal-polymer composite coated polymer, the method consisting of: providing a cellulose-based polymer substrate having a permeable, open porous structure, the cellulose-based polymer selected from the group consisting of viscose rayon, extra-long staple cotton, lyocell, mercerized cotton, modal, and combinations thereof; immersing the cellulose-based polymer substrate in a metal solution, the metal solution comprising an organometallic silver compound in an organic solvent; decomposing the metal solution in a thermally controlled environment to reduce the organometallic silver such that the metal is deposited on a surface of the cellulose-based polymer substrate; and treating the surface with a functional coating after reducing the metal solution to form the metal-polymer composite coated polymer.
  2. 2 . The method of claim 1 , wherein the metal solution is selected from the group consisting of organic or inorganic salts of copper, silver, aluminum, gold, iron, nickel, and combinations thereof.
  3. 3 . The method of claim 1 , wherein the organometallic silver compound is selected from the group consisting of silver acetate, silver octanoate, silver nonanoate, silver neodecanoate, silver undecanoate, silver dodecanoate, silver nitrate, diamminesilver (I), silver (I) hexafluoropentanedionate-cyclooctadiene, silver 2-ethylhexylcarbamate, silver phenolate, and combinations thereof.
  4. 4 . The method of claim 1 , wherein the metal solution comprises an organic solvent selected from the group consisting of xylene, acetone, toluene, benzene, n-methyl pyrrolidone, ethanol, water, and combinations thereof.
  5. 5 . The method of claim 1 , wherein the metal solution comprises an organometallic silver compound in toluene.
  6. 6 . The method of claim 1 , wherein the metal solution comprises an additive selected from the group consisting of ethyl cellulose, graphene nano-platelets, polystyrene-block-poly (ethylene-ran-butylene)-block-polystyrene-graft malefic anhydride, poly (ethylene-co-ethyl acrylate), ethylene-acrylic acid, hexadecyltrimethoxysilane, triethoxy (vinyl) silane, metallic nanoparticles, and combinations thereof.
  7. 7 . The method of claim 1 , wherein the functional coating is selected from a group consisting of ethyl cellulose, graphene nano-platelets, polystyrene-block-poly (ethylene-ran-butylene)-block-poly styrene-graft malefic anhydride, poly (ethylene-co-ethyl acrylate), ethylene-acrylic acid, hexadecyltrimethoxysilane, triethoxy (vinyl) silane, low density polyethylene, polyethylene terephthalate, poly (vinyl butryal-co-vinyl alcohol-co-vinyl acetate), poly vinyl butyral, polystyrene-block-polybutadiene-block-polystyrene, polyurethane, and combinations thereof.
  8. 8 . The method of claim 1 , further comprising, prior to immersing the cellulose-based polymer substrate in a metal solution, modifying the surface of the cellulose-based polymer substrate with a pretreatment surface modification solution.
  9. 9 . The method of claim 8 , wherein the pretreatment surface modification solution is selected from a group consisting of sulfuric acid, hydrochloric acid, hydrofluoric acid, nitric acid, phosphoric acid, perchloric acid, lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, calcium hydroxide, and combinations thereof.
  10. 10 . The method of claim 1 , wherein decomposing the metal solution comprises a continuous process.
  11. 11 . The method of claim 10 , wherein the cellulose-based polymer substrate is in contact with the metal solution for about 3 to about 12 seconds and is in the thermally controlled environment for about 40 to about 60 seconds.
  12. 12 . The method of claim 10 , wherein the cellulose-based polymer substrate is in contact with the metal solution for about 45 to about 55 seconds and is in the thermally controlled environment for about 160 to about 180 seconds.
  13. 13 . The method of claim 1 , further comprising immersing the cellulose-based polymer substrate in the metal solution, decomposing the metal solution in the thermally controlled environment, and reducing the metal solution to metal such that the metal is deposited on the surface of the cellulose-based polymer substrate more than once before treating the surface with the polymer coating.
  14. 14 . The method of claim 13 , wherein an average temperature in the thermally controlled environment is lower during a first decomposing step than in a subsequent decomposing step.
  15. 15 . The method of claim 1 , wherein an average temperature in the thermally controlled environment is in a range of about 90 to about 300° C.
  16. 16 . The method of claim 1 , wherein decomposing the metal solution in the thermally controlled environment includes maintaining conductive contact between a heating element and the cellulose-based polymer substrate.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the priority benefit of U.S. Provisional Patent App. No. 62/771,814 filed Nov. 27, 2018, which is incorporated herein by reference in its entirety. TECHNICAL FIELD The present disclosure relates generally to a thermal decomposition metallization process and conductive metal-polymer composite coated polymer substrates prepared by the provided processes. BACKGROUND Electrically conductive metal-coated polymer fibers have been proposed as a solution to the need in the art for improved conductive materials. However, there remains unmet needs in the art for improved methods of preparing metal-coated fibers. SUMMARY According to one embodiment, a method for forming a conductive metal-polymer composite coated polymer includes providing a polymer substrate and immersing the polymer substrate in a metal solution. The method further includes decomposing the metal solution in a thermally controlled environment and reducing the metal solution to metal such that the metal is deposited on a surface of the polymer substrate. After reducing the metal solution, the method includes treating the surface with a polymer coating to form the metal-polymer composite coated polymer. BRIEF DESCRIPTION OF THE DRAWINGS The present disclosure will be more readily understood from a detailed description of some example embodiments taken in conjunction with the following figures. FIG. 1 is a flowchart for a method for forming a conductive metal-polymer composite coated polymer according to an embodiment. FIG. 2 is a flowchart for a method for forming a conductive metal-polymer composite coated polymer according to an embodiment. FIG. 3 is a cross-section of a metal-coated polymer fiber bundle made according to an embodiment at 270× magnification. FIG. 4 is a cross-section of a metal-coated polymer fiber bundle made according to an embodiment at 600× magnification. FIGS. 5A-5D are surface morphology SEM images from raw mercerized cotton fiber made according to an embodiment. DETAILED DESCRIPTION In one embodiment, a method is provided for fabricating metal-coated polymer surfaces having high electrical conductivity. The polymer surfaces may include, but not be limited to, surfaces of a polymer fiber(s) or a polymer sheet(s). In some embodiments, a method comprises decomposing a metal based solution or solutions on the surface of a polymer fiber(s) or sheet(s) utilizing an in-situ thermal reduction of metal salts and coating a final functional polymer onto the polymer fiber(s) or sheet(s) to entrap the continuous, conductive metal network and create a quasi-bilayer polymer/metal composite coating that adheres to the designated fiber or sheet. In some embodiments, one or more of the steps set forth above may be repeated one or more times. In some embodiments, a method for forming a highly conductive metal-polymer composite coated polymer is provided comprising: providing a polymer substrate such as, for example, a polymer fiber or polymer sheet; immersing the polymer in a metal based solution; decomposing the metal solution in a thermally controlled environment; reducing the metal solution to metal such that conductive metal is deposited on the surface of the polymer; and subsequently treating the surface with a conformal polymer coating. Depending on the porosity of the selected substrate, the deposited metal may also be present on surfaces throughout the fiber matrix of the substrate. Adhesion and entrapment of metal to the polymer substrate depends on variety of factors, including but not limited to: interaction of polymer functional groups with solution substituents, concentration of additives in the metal solution, post-treatment functional coating, and method of thermal decomposition. In addition, depending upon which polymer substrate is chosen, a pretreatment surface modification step may be used in order to enhance susceptibility of the substrate to subsequent coatings. A variety of polymer substrates can be metallized using the thermal decomposition metallization process. Ideally the substrate has a permeable, open porous structure and high heat resistance. Substrates with high elongation and low glass transition/melting temperatures are less ideal, as expansion and contraction of the substrate can negatively impact conductive contact following metallization. High moisture regain typically serves as an indicator for a porous polymer substrate. Greater substrate surface area also allows for more adsorption of the metal solution and, in turn, more conductive polymers. Most non-cellulose-based substrates require surface modification prior to metallization, as they are non-porous and would otherwise have poor retention of metal solution, resulting in decreased adhesion characteristics upon reduction to metal. Potential substrates include cellulose-based polymers, such as viscose rayon, extra-long staple (ELS) Supima® cotton, Tencel® lyocell, mercerized cotton, Lenzing Moda