Processing of superhydrophobic, infrared transmissive, Anti-reflective nanostructured surfaces

a nanostructured surface, infrared transmissive technology, applied in the field of making superhydrophobic materials, can solve problems such as increasing the hydrophilicity of materials

Inactive Publication Date: 2017-03-23
THE UNITED STATES OF AMERICA AS REPRESENTED BY THE SECRETARY OF THE NAVY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0009]The present disclosure relates to a method of forming a hydrophobic, anti-reflective material, which is transmissive at at least one wavelength in the ultraviolet to infrared range of the electromagnetic spectrum. The method includes steps providing a substrate having a transmissive wavelength at at least one wavelength in the ultraviolet to infrared range of the electromagnetic spectrum, the substrate comprising at least one surface including nanostructures of a size smaller than the at least one wavelength, functionalizing at least one surface to provide hydroxyl groups thereon, and contacting the at least one surface with a solution comprising a hydrophobic fluoropolymer for a sufficient time to apply at least a monolayer of a fluorine-containing material on the at least one surface.

Problems solved by technology

However, fused silica and the other materials used in these approaches tend to be hydrophilic, which presents obstacles for use of the technologies in certain applications.
Moreover, the application of nanostructures to a surface may increase the hydrophilicity of a material.

Method used

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  • Processing of superhydrophobic, infrared transmissive, Anti-reflective nanostructured surfaces
  • Processing of superhydrophobic, infrared transmissive, Anti-reflective nanostructured surfaces
  • Processing of superhydrophobic, infrared transmissive, Anti-reflective nanostructured surfaces

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0067]UV grade fused-silica substrates, which were randomly pre-patterned on one side with nanostructures extending approximately 800 nm into the surface of the substrate, were subjected to an O2(g) atmosphere for 10 minutes in a March Plasma Reactive Ion Etcher under a pressure of 320 mTorr, and at a power of 200 W. The substrates were then removed, immersed and swirled for 30 seconds in hexanes that contained 0.5% 1H,1H,2H,2H-perfluorooctyl trichlorosilane (PFOTS). The substrates were immediately rinsed with hexanes, blown dry with N2(g) and placed in an oven to bake for 15 minutes at 120° C. The substrates were removed from the oven and allowed to cool.

Water Contact Angle Analysis

[0068]Water contact angle measurements were taken using the devices of Comparative Examples 1-3 and Example 1. The device of Comparative Example 1 had a contact angle indicative of a hydrophilic substance. The contact angle of the device of Comparative Example 3 was found to be nearly 0° (i.e. superhydro...

example 2

[0082]PFOTS (or similar functioning species) can be applied to other optical materials with surface anti-reflective structures to enable superhydrophobicity in other wavelength regions, such as the mid-wave infrared (MWIR) and long-wave infrared (LWIR). The application to substrate materials other than fused silica was demonstrated in Example 2 using germanium substrates. Each device using a germanium substrate had a differently shaped periodic, nanoscale surface pattern as shown in FIG. 2A, FIG. 2B, and FIG. 2C. These non-random patterns include nano-pillars (shown as GeP), truncated nano-cones (shown as GeC), and / or honeycomb patterns (shown as GeHC). The substrates were chemically treated using the same process as described in Example 1.

Water Contact Angle Analysis

[0083]Following chemical modification of the germanium substrates, the contact angle for water was measured following the procedure included above. After chemical modification with PFTOS, each of the germanium substrate...

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Abstract

Methods for producing nanostructured, hydrophobic, superhydrophobic, or hydrophilic, transmissive, anti-reflective surfaces are described. The method for providing a hydrophilic surface includes steps of providing a substrate that is transmissive at at least one wavelength in the infrared to ultraviolet range of the electromagnetic spectrum and comprises at least one surface including nanostructures of a size smaller than the at least one wavelength; and functionalizing the at least one surface with hydroxyl groups thereon. A hydrophobic or superhydrophobic surface can be provided by contacting the at least one surface with a hydrophobic fluoropolymer for a time sufficient to apply at least a monolayer of fluorine-containing material to the at least one surface. These methods provide devices having excellent transmittance and anti-reflectance properties and which are resistant to seawater.

Description

RELATED APPLICATIONS[0001]This application claims the benefit of U.S. provisional application No. 62 / 184,269, filed Jun. 25, 2015.TECHNICAL FIELD[0002]This disclosure pertains to a method of making superhydrophobic, or superhydrophilic materials having nanoscale features that impart anti-glare properties and enhanced transmittance in the ultraviolet (UV), visible and infrared (IR) region of the light spectrum. Such materials may also maintain their wettability characteristics in seawater.BACKGROUND[0003]Nature has provided numerous examples of materials with surfaces having nanoscale features that serve a practical survival purpose for living species. The material that comprises a moth's eye is one such surface. The surface of moth eye provides advantageous transmission and anti-reflection (“AR”) properties that allow a moth to see in dim light and prevents reflection of light off of the moth eye in order to help evade potential predators.[0004]Upon examination, the structure of the...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): G02B1/18G02B1/118B05D5/00B05D3/14B05D1/18
CPCG02B1/18B05D3/142G02B1/118B05D5/00B05D1/18B05D5/083B05D1/185C03C17/30C03C17/32C03C2217/732C03C2217/76B05D5/02B05D2203/35
Inventor BOYD, DARRYL A.FRANTZ, JESSE A.BAYYA, SHYAM S.BUSSE, LYNDA E.SANGHERA, JASBINDER S.KIM, WOOHONGAGGARWAL, ISHWAR D.
Owner THE UNITED STATES OF AMERICA AS REPRESENTED BY THE SECRETARY OF THE NAVY
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