Grafting of high-density poly(ethylene glycol) monolayers on Si(111)

X. Y. Zhu, Y. Jun, D. R. Staarup, R. C. Major, S. Danielson, V. Boiadjiev, W. L. Gladfelter, B. C. Bunker, A. Guo

Research output: Contribution to journalArticlepeer-review

101 Scopus citations


A strategy has been developed for the grafting of poly(ethylene glycol) (PEG) monolayers onto the atomically flat Si(111) surface. This process involves the direct interaction of the HO-functional group on PEG with a chlorine-terminated silicon surface. The resulting monolayers show exceptional flatness, with mean roughness on the angstrom scale. Film thickness is determined by ellipsometry, X-ray photoelectron spectroscopy, and atomic force microscopy. Results for different molecular weights reveal that the grafted PEG molecules are in a brushlike configuration at low molecular weight (MW = 200, 300) and a more coil-like configuration at higher molecular weight (MW = 1000, 2000). The surface density of grafted PEG molecules is significantly higher than those reported in the literature and decreases with increasing molecular weight, from 92% at MW = 300 to 35% at MW = 2000. Both the brushlike and the coil-like configurations show excellent properties of protein resistance.

Original languageEnglish (US)
Pages (from-to)7798-7803
Number of pages6
Issue number25
StatePublished - Dec 11 2001


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