Anisotropy reduction in coating of conductive films
Provided herein is a method of forming a conductive film, the method comprising: providing a coating solution having a plurality of conductive nanostructures and a fluid carrier; moving a web in a machine direction; forming a wet film by depositing the coating solution on the moving web, wherein the wet film has a first dimension extending parallel to the machine direction and a second dimension transverse to the machine direction; applying an air flow across the wet film along the second dimension, whereby at least some of the conductive nanostructures in the wet film are reoriented; and allowing the wet film to dry to provide the conductive film.
1. A conductive film, comprising:
a plurality of conductive nanostructures, wherein:
at least some of the plurality of conductive nanostructures are reoriented,
the conductive film has a first dimension and a second dimension perpendicular to the first dimension,
both the first and the second dimensions are perpendicular to a normal of the conductive film,
the conductive film has an anisotropy, which is defined as a ratio (RTD/RMD) of a first sheet resistance (RMD) and a second sheet resistance (RTD),
the first sheet resistance (RMD) is measured at a given location along the first dimension and the second sheet resistance (RTD) is measured at the given location along the second dimension, and
the anisotropy is greater than 1 and less than 1.5 according to a reorientation of the at least some of the plurality of conductive nanostructures.
2. The conductive film of claim 1 , wherein:
the conductive film has a plurality of anisotropies, each of the plurality of anisotropies is defined as the ratio (RTD/RMD) of the first sheet resistance (RMD) and the second sheet resistance (RTD),
for each of the plurality of anisotropies, the first sheet resistance (RMD) is measured at a given location along the first dimension and the second sheet resistance (RTD) is measured at the given location along the second dimension,
the conductive film has a maximum anisotropy and a minimum anisotropy among the plurality of anisotropies, and
a difference between the maximum anisotropy and the minimum anisotropy is less than 25% of the minimum anisotropy according to a reorientation of the at least some of the plurality of conductive nanostructures.
3. The conductive film of claim 2 , wherein the difference between the maximum anisotropy and the minimum anisotropy is less than 10% of the minimum anisotropy.
4. The conductive film of claim 1 , wherein the plurality of conductive nanostructures have a hollow core.
5. The conductive film of claim 1 , wherein the plurality of conductive nanostructures have a solid core.
6. The conductive film of claim 1 , wherein the plurality of conductive nanostructures are isotropically-shaped.
7. The conductive film of claim 1 , wherein the plurality of conductive nanostructures are anisotropically-shaped.
8. The conductive film of claim 1 , wherein the plurality of conductive nanostructures are silver nanowires.