Tunable hydrophilicity on a hydrophobic fluorocarbon polymer coating on silicon

Kai Kolari, Ari Hokkanen

Research output: Contribution to journalArticleScientificpeer-review

12 Citations (Scopus)

Abstract

An efficient, economic, reliable, and repeatable patterning procedure of hydrophobic surfaces was developed. A fluorocarbon polymer derived from the C4F8 gas in an inductively coupled plasma etcher was used as the hydrophobic coating. For a subsequent patterning of hydrophilic apertures on the polymer, a short O2 plasma exposure through a silicon shadow mask was utilized. The overall hydrophilicity of the patterned surface can be tuned by the duration of the O2 plasma exposure, and also by the density and the size of the hydrophilic apertures. The laborious photolithography and tricky lift-off procedures are avoided. Optimization of the whole patterning process is explained thoroughly and supported with experimental data. The hydrophilic adhesion of the patterned polymer was evaluated with aqueous droplets, which were studied on matrices of the hydrophilic apertures of different sizes. The deposition parameters of the fluorocarbon polymer, the size of the droplet required to enable rolling on the patterned surface, and the duration of the O2 plasma exposure were considered as the main parameters. To determine the achievable resolution of the patterning procedure, the subsurface etching beneath the shadow mask was evaluated. The results show that a resolution of less than 10μm can be achieved. The simple hydrophilic patterning procedure described here can be used for the production of on-plane microfluidics, where a controlled adhesion or decohesion of 8–50μl droplets on the surface with a variable hydrophilicity from one location to another can be achieved.
Original languageEnglish
Pages (from-to)1005-1011
Number of pages7
JournalJournal of Vacuum Science and Technology A: Vacuum, Surfaces and Films
Volume24
Issue number4
DOIs
Publication statusPublished - 2006
MoE publication typeA1 Journal article-refereed

Fingerprint

Fluorocarbon Polymers
Fluorocarbons
fluorocarbons
Hydrophilicity
Silicon
coatings
Coatings
apertures
polymers
silicon
Polymers
Plasmas
Masks
adhesion
masks
Adhesion
Inductively coupled plasma
Photolithography
photolithography
Microfluidics

Keywords

  • polymer films
  • sputter etching
  • adhesion
  • plasma
  • plasma deposition
  • plasma deposited coatings
  • etching
  • fluorocarbons
  • polymer coatings
  • silicon

Cite this

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title = "Tunable hydrophilicity on a hydrophobic fluorocarbon polymer coating on silicon",
abstract = "An efficient, economic, reliable, and repeatable patterning procedure of hydrophobic surfaces was developed. A fluorocarbon polymer derived from the C4F8 gas in an inductively coupled plasma etcher was used as the hydrophobic coating. For a subsequent patterning of hydrophilic apertures on the polymer, a short O2 plasma exposure through a silicon shadow mask was utilized. The overall hydrophilicity of the patterned surface can be tuned by the duration of the O2 plasma exposure, and also by the density and the size of the hydrophilic apertures. The laborious photolithography and tricky lift-off procedures are avoided. Optimization of the whole patterning process is explained thoroughly and supported with experimental data. The hydrophilic adhesion of the patterned polymer was evaluated with aqueous droplets, which were studied on matrices of the hydrophilic apertures of different sizes. The deposition parameters of the fluorocarbon polymer, the size of the droplet required to enable rolling on the patterned surface, and the duration of the O2 plasma exposure were considered as the main parameters. To determine the achievable resolution of the patterning procedure, the subsurface etching beneath the shadow mask was evaluated. The results show that a resolution of less than 10μm can be achieved. The simple hydrophilic patterning procedure described here can be used for the production of on-plane microfluidics, where a controlled adhesion or decohesion of 8–50μl droplets on the surface with a variable hydrophilicity from one location to another can be achieved.",
keywords = "polymer films, sputter etching, adhesion, plasma, plasma deposition, plasma deposited coatings, etching, fluorocarbons, polymer coatings, silicon",
author = "Kai Kolari and Ari Hokkanen",
year = "2006",
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language = "English",
volume = "24",
pages = "1005--1011",
journal = "Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films",
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}

Tunable hydrophilicity on a hydrophobic fluorocarbon polymer coating on silicon. / Kolari, Kai; Hokkanen, Ari.

In: Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films, Vol. 24, No. 4, 2006, p. 1005-1011.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Tunable hydrophilicity on a hydrophobic fluorocarbon polymer coating on silicon

AU - Kolari, Kai

AU - Hokkanen, Ari

PY - 2006

Y1 - 2006

N2 - An efficient, economic, reliable, and repeatable patterning procedure of hydrophobic surfaces was developed. A fluorocarbon polymer derived from the C4F8 gas in an inductively coupled plasma etcher was used as the hydrophobic coating. For a subsequent patterning of hydrophilic apertures on the polymer, a short O2 plasma exposure through a silicon shadow mask was utilized. The overall hydrophilicity of the patterned surface can be tuned by the duration of the O2 plasma exposure, and also by the density and the size of the hydrophilic apertures. The laborious photolithography and tricky lift-off procedures are avoided. Optimization of the whole patterning process is explained thoroughly and supported with experimental data. The hydrophilic adhesion of the patterned polymer was evaluated with aqueous droplets, which were studied on matrices of the hydrophilic apertures of different sizes. The deposition parameters of the fluorocarbon polymer, the size of the droplet required to enable rolling on the patterned surface, and the duration of the O2 plasma exposure were considered as the main parameters. To determine the achievable resolution of the patterning procedure, the subsurface etching beneath the shadow mask was evaluated. The results show that a resolution of less than 10μm can be achieved. The simple hydrophilic patterning procedure described here can be used for the production of on-plane microfluidics, where a controlled adhesion or decohesion of 8–50μl droplets on the surface with a variable hydrophilicity from one location to another can be achieved.

AB - An efficient, economic, reliable, and repeatable patterning procedure of hydrophobic surfaces was developed. A fluorocarbon polymer derived from the C4F8 gas in an inductively coupled plasma etcher was used as the hydrophobic coating. For a subsequent patterning of hydrophilic apertures on the polymer, a short O2 plasma exposure through a silicon shadow mask was utilized. The overall hydrophilicity of the patterned surface can be tuned by the duration of the O2 plasma exposure, and also by the density and the size of the hydrophilic apertures. The laborious photolithography and tricky lift-off procedures are avoided. Optimization of the whole patterning process is explained thoroughly and supported with experimental data. The hydrophilic adhesion of the patterned polymer was evaluated with aqueous droplets, which were studied on matrices of the hydrophilic apertures of different sizes. The deposition parameters of the fluorocarbon polymer, the size of the droplet required to enable rolling on the patterned surface, and the duration of the O2 plasma exposure were considered as the main parameters. To determine the achievable resolution of the patterning procedure, the subsurface etching beneath the shadow mask was evaluated. The results show that a resolution of less than 10μm can be achieved. The simple hydrophilic patterning procedure described here can be used for the production of on-plane microfluidics, where a controlled adhesion or decohesion of 8–50μl droplets on the surface with a variable hydrophilicity from one location to another can be achieved.

KW - polymer films

KW - sputter etching

KW - adhesion

KW - plasma

KW - plasma deposition

KW - plasma deposited coatings

KW - etching

KW - fluorocarbons

KW - polymer coatings

KW - silicon

U2 - 10.1116/1.2207149

DO - 10.1116/1.2207149

M3 - Article

VL - 24

SP - 1005

EP - 1011

JO - Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films

JF - Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films

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