A molecular simulation study of an organosilane self-assembled monolayer/ SiO2 substrate interface

Hideaki Yamamoto, Takanobu Watanabe, Iwao Ohdomari

    Research output: Contribution to journalArticle

    14 Citations (Scopus)

    Abstract

    The bonding network of an alkylsilane self-assembled monolayer (SAM) Si O2 substrate interface is investigated by means of canonical Monte Carlo (MC) simulations. SAMSi O2 systems with different interfacial bonding topologies are sampled by the Metropolis MC method, and the AMBER potential with a newly developed organosilicon parameters are used to obtain an optimized structure with a given bonding topology. The underlying substrates are modeled as hydroxy-terminated (100) or (111) cristobalites. The SAMSi O2 interface is characterized by a polysiloxane bonding network which comprises anchoring bonds and cross-linking bonds, namely, molecule-substrate and molecule-molecule Si-O-Si bonds, respectively. We show that at thermal equilibrium, the ratio of the number of anchoring bonds to cross-linking bonds decreases as a total Si-O-Si bond density increases, and that nevertheless, number of anchoring bonds always dominate over that of cross-linking bonds. Moreover we show that the total Si-O-Si bond density strongly affects the lateral ordering of the alkylsilane molecules, and that increase in the Si-O-Si bond density disorders the molecular packing. Our results imply that a lab-to-lab variation in the experimentally prepared SAMs can be attributed to different Si-O-Si bond densities at the SAMSi O2 interface.

    Original languageEnglish
    Article number164710
    JournalJournal of Chemical Physics
    Volume128
    Issue number16
    DOIs
    Publication statusPublished - 2008

    Fingerprint

    Self assembled monolayers
    Molecules
    Substrates
    molecules
    topology
    simulation
    Topology
    Siloxanes
    polysiloxanes
    Monte Carlo method
    Monte Carlo methods
    disorders

    ASJC Scopus subject areas

    • Atomic and Molecular Physics, and Optics

    Cite this

    A molecular simulation study of an organosilane self-assembled monolayer/ SiO2 substrate interface. / Yamamoto, Hideaki; Watanabe, Takanobu; Ohdomari, Iwao.

    In: Journal of Chemical Physics, Vol. 128, No. 16, 164710, 2008.

    Research output: Contribution to journalArticle

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