Observation of dynamical heterogeneities and their time evolution on the surface of an amorphous polymer

Hung K. Nguyen, Dong Wang, Thomas P. Russell, Ken Nakajima

    Research output: Contribution to journalArticlepeer-review

    17 Citations (Scopus)

    Abstract

    Although the formation of dynamic heterogeneities in glass-forming materials is believed to play an essential role in determining their properties as the glass transition is approached, direct imaging of these heterogeneities remains a challenge. Here, we report on a direct observation of nanoscale dynamic heterogeneities and their time evolution over ∼103 s on the surface of a glassy polymer, polystyrene (PS), using atomic force microscopy with a 1 nm radius tip. The length scale of these heterogeneities was measured to be ∼2.1 nm and the lifetime was determined to be ∼102 s, in agreement with the length and time scales of heterogeneous dynamics reported for bulk polymers around the glass transition. These results are consistent with the existence of a very thin liquid-like layer at the glassy polymer surface. The validity of the method is confirmed by comparing the properties of surface dynamics of neat and plasticized films.

    Original languageEnglish
    Pages (from-to)1425-1433
    Number of pages9
    JournalSoft Matter
    Volume11
    Issue number7
    DOIs
    Publication statusPublished - 2015 Feb 21

    ASJC Scopus subject areas

    • Chemistry(all)
    • Condensed Matter Physics

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