Structurally-colored articles and methods for making and using structurally-colored articles
One or more aspects of the present disclosure are directed to bladders that incorporate a multi-layer optical film that impart a structural color to the bladder. The present disclosure is also directed to articles including the bladders having a multi-layer optical film, and methods for making articles and bladders having a multi-layer optical film.
1. An article of footwear comprising:
a footwear upper; and
an inflated bladder comprising:
a top wall operably secured to the footwear upper;
a bottom wall opposite the top wall; and
one or more sidewalls extending between the top wall and the bottom wall of the inflated bladder, wherein the top wall, the bottom wall, and the one or more sidewalls collectively define an interior region of the inflated bladder, and wherein the one or more sidewalls each comprise an interior-facing side and an exterior-facing side; and
a multi-layer optical film operably disposed on the interior-facing side or exterior-facing side of at least one of the one or more sidewalls to impart a structural color having at least one hue to the one or more sidewalls;
wherein the multi-layer optical film comprises:
a first layer compositionally comprising a non-oxide metal; and
a second layer disposed on the first layer and compositionally comprising a first metal oxide; and
wherein the multi-layer optical film is a multi-layer reflector or a multi-layer filter comprising at least two adjacent layers having different refractive indices and at least one of the layers of the multi-layer reflector or filter has a thickness that is about one-fourth of the wavelength of the visible light to be reflected by the multi-layer optical film to produce the structural color.
2. The article of footwear of claim 1 , wherein the first metal oxide is titanium dioxide or silicon dioxide.
3. The article of footwear of claim 1 , wherein the multi-layer optical film comprises:
a third layer compositionally comprising a second metal oxide that is different from the first metal oxide.
4. The article of footwear of claim, wherein at least one of the layers of the multilayer reflector or multi-layer filter comprises a material selected from the group consisting of: silicon dioxide, titanium dioxide, zinc sulfide, magnesium fluoride, tantalum pentoxide, and a combination thereof.
5. The article of footwear of claim 1 , wherein the structural color imparted to the one or more sidewalls has a single hue regardless of viewing angle.
6. The article of footwear of claim 1 , wherein the structural color imparted to the one or more sidewalls has a metallic appearance.
7. The article of footwear of claim 1 , wherein the structural color imparted to the one or more sidewalls has two or more hues.
8. The article of footwear of claim 1 , wherein each color visible at each possible angle of observation is assigned to a single hue selected from the group consisting of the primary, secondary and tertiary colors on the red yellow blue (RYB) color wheel, all of the assigned hues fall into a single hue group, wherein the single hue group is one of a) green-yellow, yellow, and yellow-orange; b) yellow, yellow-orange and orange; c) yellow-orange, orange, and orange-red; d) orange-red, and red-purple; e) red, red-purple, and purple; f) red-purple, purple, and purple-blue; g) purple, purple-blue, and blue; h) purple-blue, blue, and blue-green; i) blue, blue-green and green; and j) blue-green, green, and green-yellow.
9. The article of footwear of claim 1 , wherein the structural color produced by the multi-layer optical film is different from the color of the underlying bladder wall.
10. The article of footwear of claim 1 , wherein the multi-layer optical film contains no pigments and no dyes.
11. The article of footwear of claim 1 , wherein the bladder wall further includes an average wall thickness between the interior-facing side and exterior-facing side that is less than 5 millimeters.
12. The article of footwear of claim 1 , wherein the multi-layer optical film has from 2 to 20 layers, each layer independently having a thickness of about 10 to 500 nanometers.
13. The article of footwear of claim 1 , wherein the multi-layer optical film has from 2 to 20 layers, each layer independently having a thickness of about 10 to 500 nanometers, wherein the multi-layer optical film contains no pigments and no dyes, and the structural color produced by the multi-layer optical film is a single-hued color.
14. The article of footwear of claim 1 , further comprising a primer layer disposed on the multi-layer optical film.
15. The article of footwear of claim 1 , wherein the multi-layer optical film, as disposed onto the bladder, when measured according to the CIE 1976 color space under a given illumination condition at two observation angles between −15 degrees and +60 degrees, has a first color measurement at a first angle of observation having coordinates L 1 * and a 1 * and b 1 *, and a second color measurement at a second angle of observation having coordinates L 2 * and a 2 * and b 2 *, wherein the L 1 * and L 2 * values may be the same or different, wherein the a 1 * and a 2 * coordinate values may be the same or different, wherein the b 1 * and b 2 * coordinate values may be the same or different, and wherein the ΔE* ab between the first color measurement and the second color measurement is less than or equal to about 100, where ΔE* ab =[(L 1 *−L 2 *) 2 +(a 1 *−a 2 *) 2 +(b 1 *−b 2 *) 2 ] 1/2 .
16. The article of footwear of claim 1 , wherein the inflated bladder further comprises a plurality of topographical structures extending from the interior-facing or exterior-facing side of at least one of the one or more sidewalls such that the multi-layer optical film covers the plurality of topographical structures.
17. The article of footwear of claim 16 , wherein the first side of the multi-layer optical film covers the plurality of topographical structures, and the first layer of the multi-layer optical film at least partially conforms to the plurality of topographical structures.
18. The article of footwear of claim 1 , further comprising a gas retained within the interior region of the bladder.
19. The article of footwear of claim 18 , wherein the gas consists essentially of nitrogen.
20. The article of footwear of claim 18 , wherein the bladder wall exhibits a gas transmission rate of 15 cm 3 /m 2 ·atm·day or less for an average wall thickness of 20 mils.