Nanotextured silica surfaces with robust superhydrophobicity and omnidirectional broadband supertransmissivity

Kyoo Chul Park, Hyungryul J. Choi, Chih Hao Chang, Robert E. Cohen, Gareth H. McKinley*, George Barbastathis

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

338 Scopus citations

Abstract

Designing multifunctional surfaces that have user-specified interactions with impacting liquids and with incident light is a topic of both fundamental and practical significance. Taking cues fromnature, we use tapered conical nanotextures to fabricate the multifunctional surfaces; the slender conical features result in large topographic roughness, while the axial gradient in the effective refractive index minimizes reflection through adiabatic index-matching between air and the substrate. Precise geometric control of the conical shape and slenderness of the features as well as periodicity at the nanoscale are all keys to optimizing the multifunctionality of the textured surface, but at the same time, these demands pose the toughest fabrication challenges. Here we report a systematic approach to concurrent design of optimal structures in the fluidic and optical domains and a fabrication procedure that achieves the desired aspect ratios and periodicities with few defects and large pattern area. Our fabricated nanostructures demonstrate structural superhydrophilicity or, in combination with a suitable chemical coating, robust superhydrophobicity. Enhanced polarization-independent optical transmission exceeding 98% has also been achieved over a broad range of bandwidth and incident angles. These nanotextured surfaces are also robustly antifogging or self-cleaning, offering potential benefits for applications such as photovoltaic solar cells.

Original languageEnglish (US)
Pages (from-to)3789-3799
Number of pages11
JournalACS nano
Volume6
Issue number5
DOIs
StatePublished - May 22 2012

Keywords

  • Antifogging
  • Antireflective
  • Enhanced transmission
  • High aspect ratio nanostructure
  • Self-cleaning
  • Wetting

ASJC Scopus subject areas

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)

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