Graphite materials and devices with surface micro-texturing
Flexible graphite and other graphite materials with surface micro-texturing, and methods and apparatuses for micro-texturing the surface of flexible graphite and other graphite materials are provided. Micro-texturing can be used to modify wettability and/or adhesion characteristics of a flexible graphite surface. Micro-textured flexible graphite materials can be advantageously used in applications where the material is in contact with liquid water or other liquids.
1. A method for making a material or an article, said method comprising micro-texturing at least a portion of at least one major surface of a flexible graphite material with an array of features and forming said material or said article into a component of a fuel cell, wherein at least one dimension of said array of features and/or a spacing between features in said array of features is less than 100 μm, the component of the fuel cell comprises a flow field plate comprising flow channels, and the array of features is within the flow channels.
2. The method of claim 1 wherein at least one dimension of said array of features or a spacing between features in said array of features is in the range between and inclusive of 10 μm to 100 μm.
3. The method of claim 1 wherein at least one dimension of said array of features or a spacing between features in said array of features is in the range between and inclusive of 10 μm to 50 μm.
4. The method of claim 1 wherein a depth or a height of said array of features is in the range between and inclusive of 15 μm to 50 μm and a spacing between features in said array of features is in the range between and inclusive of 15 μm to 25 μm.
5. The method of claim 1 wherein said micro-texturing comprises embossing said at least a portion of said at least one major surface of said flexible graphite material with said array of features.
6. The method of claim 1 wherein said micro-texturing comprises embossing said at least a portion of said at least one major surface of said flexible graphite material using a die.
7. The method of claim 1 wherein said micro-texturing comprises embossing said at least a portion of said at least one major surface of said flexible graphite material using a wafer die.
8. The method of claim 1 wherein said micro-texturing comprises embossing said at least a portion of said at least one major surface of said flexible graphite material using a roller embossing device.
9. The method of claim 1 wherein said micro-texturing increases the hydrophobicity of said at least a portion of said at least one major surface of said flexible graphite material.
10. The method of claim 1 wherein the contact angle of a water droplet on said flexible graphite material prior to said micro-texturing is less than 70°, and the contact angle of a water droplet on said at least a portion of said at least one major surface of said flexible graphite material that is micro-textured with said array of features is greater than 90°.
11. The method of claim 1 wherein said method further comprises, prior to said micro-texturing, reducing the roughness of said at least a portion of said at least one major surface of said flexible graphite material by pressing said flexible graphite material against a smooth surface.
12. The method of claim 1 wherein said flexible graphite material consists essentially of graphite.
13. The method of claim 1 wherein said flexible graphite material comprises a resin.
14. A method for making a material or an article, said method comprising embossing at least a portion of at least one major surface of a flexible graphite material with an array of features, using a roller embosser patterned with said array of features or a die patterned with said array of features, and forming said material or said article into a component of a fuel cell wherein at least one dimension of said array of features and a spacing between features in said array of features are less than 100 μm, the fuel cell comprises a flow field plate comprising flow channels, and the array of features is within the flow channels.