Photochemical fabrication of a well-defined diblock copolymer nanotemplate using 172-nm vacuum ultraviolet light

Atsushi Hozumi, Shuichi Asakura, Akio Fuwa, Naoto Shirahata

    Research output: Contribution to journalArticle

    6 Citations (Scopus)

    Abstract

    Well-ordered nanopore arrays were successfully prepared from polystyrene (PS) and poly(methyl methacrylate) (PMMA) diblock copolymer (DBC) film based on a photochemical approach using 172-nm vacuum ultraviolet (VUV) light. Since the etching selectivity between the PS and PMMA domains against activated oxygen species generated by the VUV irradiation of atmospheric oxygen molecules was markedly different, PMMA was preferentially decomposed, resulting in the formation of PS nanopore arrays. Both the photoetching rate and final morphology depended greatly on the atmospheric pressure during VUV irradiation. Since at 10 Pa the PS domains degraded less due to the shortage of oxygen molecules in the atmosphere, the residual matrix kept its fine nanostructures up to 40 min of irradiation. The matrix could be eliminated completely when irradiation was extended to 60 min at this pressure. On the other hand, at 103 Pa the DBC film was removed completely from the substrate within 10 min of irradiation. However, at 103 Pa, not only the decomposition of the PMMA domains, but also the photoetching rate of the PS domains accelerated significantly resulting in marked distortion of the generated nanostructures. By selecting an appropriate atmospheric pressure and time for VUV irradiation, we were able to control both nanoarray formation and elimination without the use of any physical and/or chemical treatment.

    Original languageEnglish
    Pages (from-to)875-878
    Number of pages4
    JournalJournal of Colloid and Interface Science
    Volume285
    Issue number2
    DOIs
    Publication statusPublished - 2005 May 15

    Keywords

    • 172-nm vacuum ultraviolet light
    • Diblock copolymer
    • Nanopore array
    • Photoetching

    ASJC Scopus subject areas

    • Colloid and Surface Chemistry
    • Physical and Theoretical Chemistry
    • Surfaces and Interfaces

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