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EP-4735244-A1 - COATED STRUCTURED SUBSTRATES AND METHODS OF MAKING SAME

EP4735244A1EP 4735244 A1EP4735244 A1EP 4735244A1EP-4735244-A1

Abstract

The present disclosure provides a coated structured article. The article includes a substrate with a structured major surface including features, in which the structured major surface includes protruding features and/or recessed features. The article also includes a coating disposed on at least a portion of the features, the coating including a first material and a second material. The first material has a first binding group and the second material has a second binding group, and the first binding group and the second binding group have complementary interactions. A method of making the article is also provided. The method includes depositing layers using layer-by-layer self-assembly to form a coating on a structured substrate.

Inventors

  • TIU, Brylee David B.
  • STENSVAD, Karl K.
  • NELSON, Caleb T.
  • PIETZ, Brandon R.
  • BEDOYA, CEDRIC
  • SOLOMON, JEFFREY L.
  • SCHMIDT, DANIEL J.
  • TARNOWSKI, David J.

Assignees

  • 3M Innovative Properties Company

Dates

Publication Date
20260506
Application Date
20240520

Claims (20)

  1. What is claimed is: 1. An article comprising: a substrate comprising a structured major surface comprising features, wherein the structured major surface comprises protruding features, recessed features, or a combination thereof; and a coating disposed on at least a portion of the features, the coating comprising a first material and a second material, wherein the first material comprises a first binding group and the second material comprises a second binding group, and wherein the first binding group and the second binding group have complementary interactions.
  2. 2. The article of claim 1, wherein the features have a pitch that is less than half of a predetermined wavelength of light.
  3. 3. The article of claim 1 or claim 2, wherein the coating is a refractive index contrast layer comprising a refractive index contrast material adjacent to the structured major surface of the substrate forming a structured bilayer with a structured interface, wherein the structured bilayer acts locally on an amplitude, phase, or polarization of light, or a combination thereof and imparts a light phase shift that varies as a function of position of the structured bilayer on the substrate, and the light phase shift of the structured bilayer defines a predetermined operative phase profile.
  4. 4. The article of any of claims 1 to 3, wherein the coating comprises a three-dimensional porous matrix, wherein the first material comprises nanoparticles.
  5. 5. The article of claim 4, wherein the second material comprises a polyelectrolyte.
  6. 6. The article of claim 4, wherein the second material comprises nanoparticles.
  7. 7. The article of any of claims 4 to 6, wherein the nanoparticles comprise silicon dioxide.
  8. 8. The article of any of claims 4 to 7, wherein the coating comprises a third material disposed in at least a portion of a plurality of pores of the porous matrix.
  9. 9. The article of claim 8, wherein the third material comprises a silicon-containing material.
  10. 10. The article of claim 9, wherein the third material comprises at least one of polydimethylsiloxane, a polysilsesquioxane, a polysiloxane, a silicone, a silicone acrylate, a silicate, a polycarbosilane, a polysilazane, or a siloxane-organic copolymer.
  11. 11. The article of any of claims 1 to 10, wherein the features comprise a top surface opposite the substrate and wherein the top surface of at least a portion of the features lacks the coating disposed thereon.
  12. 12. The article of any of claims 1 to 10, further comprising a layer of an inorganic material disposed on the coating opposite the substrate.
  13. 13. The article of any of claims 1 to 12, wherein the coating and the features have different refractive indices from each other.
  14. 14. The article of any of claims 1 to 13, wherein a difference in refractive index of the coating from the refractive index of the features (ΔRI) is at least 0.75.
  15. 15. The article of any of claims 1 to 14, wherein the structured major surface comprises a plurality of protruding features each comprising a base extending from the major surface and a top distal to the major surface, wherein a diameter at the base is equal to or greater than a diameter at the top, and wherein a plurality of coated features each has a diameter at a top of the protruding feature that is greater than a diameter of a base.
  16. 16. The article of any of claims 1 to 15, exhibiting a transmission of at least 80% of light in a wavelength range of 1000 nanometers (nm) to 2000 nm.
  17. 17. The article of any of claims 1 to 16, exhibiting optical metasurface properties within a wavelength range of at least one of 700 nm to 2500 nm or 1300 nm to 6000 nm.
  18. 18. A method of making an article, the method comprising: obtaining a substrate comprising a structured major surface comprising features, wherein the structured major surface comprises protruding features, recessed features, or a combination thereof; and disposing onto the structured major surface a plurality of layers deposited by layer-by-layer self- assembly, thereby forming a coating disposed on at least a portion of the features, the coating comprising a first material and a second material, wherein the first material comprises a first binding group and the second material comprises a second binding group, and wherein the first binding group and the second binding group have complementary interactions.
  19. 19. The method of claim 18, further comprising depositing a second coating on the coating opposite the substrate, optionally wherein the depositing is performed using vapor deposition.
  20. 20. The method of claim 18 or claim 19, wherein the coating comprises a three-dimensional porous matrix, and wherein the method further comprises depositing a third material into a plurality of pores of the porous matrix, optionally wherein the third material is deposited by applying a solution of the third material onto the coating.

Description

COATED STRUCTURED SUBSTRATES AND METHODS OF MAKING SAME BACKGROUND Various structured substrates are known, having engineered structured shapes. Further developments in articles having structured surfaces would be desirable. SUMMARY In a first aspect, an article is provided. The article comprises a substrate comprising a structured major surface comprising features, wherein the structured major surface comprises protruding features, recessed features, or a combination thereof. The article also comprises a coating disposed on at least a portion of the features, the coating comprising a first material and a second material. The first material comprises a first binding group and the second material comprises a second binding group, and the first binding group and the second binding group have complementary interactions. In a second aspect a method of making an article is provided. The method comprises obtaining a substrate comprising a structured major surface comprising features, wherein the structured major surface comprises protruding features, recessed features, or a combination thereof. The method further comprises disposing onto the structured major surface a plurality of layers deposited by layer-by-layer self-assembly, thereby forming a coating disposed on at least a portion of the features. The coating comprises a first material and a second material. The first material comprises a first binding group and the second material comprises a second binding group, and the first binding group and the second binding group have complementary interactions. Infrared (IR) metasurfaces are planar devices composed of subwavelength structures (i.e., meta- atoms) and can steer the polarization, phase, and amplitude of electromagnetic waves at the wavelengths between 0.700 micrometers and 300 micrometers. Their ability to control the properties of electromagnetic waves, particularly polarization, in the longer IR wavelength region allows these materials to play an important role for various applications including optical sensing, thermal imaging, and free-space wireless communication. Fabricating metasurfaces based on silicon is widely known since silicon-based processes are common and readily available for wafer-based processes (e.g., up to 300 mm in diameter). However, many possible use cases require large part sizes, flexible substrates, or extremely high part volumes. In those cases, processing on flexible films would likely be preferrable if equivalent capabilities existed. There are distinct challenges when trying to transfer silicon metasurface processes to roll-to-roll (R2R) formats. For instance, the high temperatures required for deposition and etching would be damaging to most polymeric film substrates; IR wavelength functions require larger features when compared to visible wavelength metasurfaces, resulting in longer deposition times to generate thicker layers and increasing heat to the substrate; thick inorganic layers can be fragile yet highly stressed on flexible films, which can lead to web- handing challenges as well as fracturing or poor adhesion of the deposited layers; and materials to be used in the final construction must have appropriate optical properties in the desired IR wavelength region. Articles according to the present disclosure are formed using layer-by-layer assembly of a coating on a structured substrate, which can be coated using a R2R format at temperatures of 100 °C or less. The above summary of the present disclosure is not intended to describe each disclosed embodiment or every implementation of the present disclosure. The description that follows more particularly exemplifies illustrative embodiments. In several places throughout the application, guidance is provided through lists of examples, which examples may be used in various combinations. In each instance, the recited list serves only as a representative group and should not be interpreted as an exclusive list. BRIEF DESCRIPTION OF THE DRAWINGS FIG.1 is a flow chart of an exemplary method according to the present disclosure. FIG.2 is a scanning electron microscopy (SEM) image of a cross-section of a portion of an exemplary article according to the present disclosure. FIG.3 is an SEM image of a cross-section of a portion of another exemplary article according to the present disclosure. FIG.4 is a schematic cross-sectional view of a stack of bi-layers. FIG.5 is a schematic cross-sectional of a portion of a further exemplary article according to the present disclosure. FIG.6A is an SEM image of a cross-section of a portion of a structured substrate. FIG.6B is an SEM image of a cross-section of a portion of an exemplary article according to the present disclosure, including a coating on the substrate of FIG.6A. FIG.7 is an SEM image of a cross-section of a portion of an exemplary coating according to the present disclosure. FIG.8 is an SEM image of a cross-section of a portion of another exemplary coating according to the