Sliding behavior of water drops on sol-gel derived hydrophobic silica films

Sanjay S. Latthe, Sunetra L. Dhere, Charles Kappenstein, Hiroaki Imai, V. Ganesan, A. Venkateswara Rao, Pratap B. Wagh, Satish C. Gupta

Research output: Contribution to journalArticlepeer-review

39 Citations (Scopus)

Abstract

Control on the wettability of solid state materials is a classical and key issue in surface engineering. Optically transparent methyltriethoxysilane (MTES)-based silica films with water sliding angle as low as 9° were successfully prepared by two-step sol-gel co-precursor method. The emphasis is given to the effect of trimethylethoxysilane (TMES) as a co-precursor on water sliding behavior of silica films. The coating sol was prepared with molar ratio of methyltriethoxysilane (MTES), methanol (MeOH), acidic water (0.01 M, oxalic acid) and basic water (12 M, NH 4 OH) kept constant at 1:12.73:3.58:3.58 respectively, and the molar ratio of TMES/MTES (M) was varied from 0 to 0.22. The static water contact angle as high as 120° and the water sliding angle as low as 9° was obtained by keeping the molar ratio (M) of TMES/MTES at 0.22. When the modified films were cured at temperature higher than 280 °C, the films became superhydrophilic. Further, the humidity study was carried out at a relative humidity of 90% at 30 °C over 60 days. We characterized the water repellent silica films by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), % of optical transmission, humidity tests and static and dynamic water contact angle (CA) measurements.

Original languageEnglish
Pages (from-to)3259-3264
Number of pages6
JournalApplied Surface Science
Volume256
Issue number10
DOIs
Publication statusPublished - 2010 Mar 1

Keywords

  • Humidity
  • Hydrophobicity
  • Sol-gel process
  • Stability
  • Wetting

ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics
  • Physics and Astronomy(all)
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films

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