Patterning by Etching at the Nanoscale (PENs) on Si(111) through the controlled etching of PDMS

Mathew Perring, Michael Mitchell, Paul J.A. Kenis, Ned B. Bowden

Research output: Contribution to journalArticle


Patterned polymer brushes were grown from organic monolayers on Si(111) using ring-opening metathesis polymerization catalyzed by the Grubbs' first generation catalyst. The Grubbs' catalyst reacted through cross metathesis with an olefin-terminated monolayer on Si(111) such that it was attached to the monolayer. Next, a polydimethylsiloxane slab patterned in bas-relief was placed on this surface to form microchannels. Undecenoic acid was added to the microchannels to react with and remove the Grubbs' catalyst from the surface exposed in the microchannels. Next, the microchannels were etched by tens of nanometers to several micrometers with F-. This etching exposed fresh monolayers on the silicon terminated with the Grubbs' catalyst. A solution of bicyclo[2.2.1]hept-5-ene-2-carboxylic acid was added to the microchannels and polymer brushes grew by ring-opening metathesis polymerization only on the newly exposed surface. A range of polymer brushes with widths from 70 nm to several micrometers was fabricated. This method is exciting because an entire surface can be patterned simultaneously and it is not limited by the wavelength of light. Rather, the width of the polymer brushes is determined by the amount of polydimethylsiloxane that is etched from the microchannels. In addition, this method can be used to pattern surfaces inside of existing microchannels. These polymer brushes were characterized by a combination of methods including X-ray photoelectron spectroscopy, scanning Auger spectroscopy, scanning electron microscopy, and optical microscopy.

Original languageEnglish (US)
Pages (from-to)2903-2909
Number of pages7
JournalChemistry of Materials
Issue number11
StatePublished - May 29 2007

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Chemistry

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