Surface-chemistry technology for microfluidics

Winky L W Hau, Dieter W. Trau, Nikolaus J. Sucher, Man Wong, Yitshak Zohar

Research output: Contribution to journalArticle

79 Scopus citations


A new technology to pattern surface charges, either negatively or positively, using a standard photolithography process is introduced. A positively charged poly(allylamine hydrochloride) (PAH) layer is coated onto a negatively charged silicon oxide surface by electrostatic self-assembly (ESA). Combined with photolithography in a lift-off-based process, several different surface charge patterns were successfully produced. Due to definition of the pattern by photolithography, no limitations in the pattern geometry exist. Any surface charge pattern can be created to enable fine control of fluid motion in microfluidic devices. Physical properties of this PAH layer were characterized. The generation of a bi-directional shear flow was demonstrated by using alternating longitudinal surface charge pattern with a single driving force, i.e. an externally applied electric field inside a microchannel.

Original languageEnglish (US)
Pages (from-to)272-278
Number of pages7
JournalJournal of Micromechanics and Microengineering
Issue number2
Publication statusPublished - Mar 2003
Externally publishedYes


ASJC Scopus subject areas

  • Computational Mechanics
  • Mechanics of Materials
  • Materials Science(all)
  • Instrumentation

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