Kandar AK, Basu JK. Experimental evidence for interplay of dynamic heterogeneity and finite-size effect in glassy polymers.
THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2011;
34:95. [PMID:
21947894 DOI:
10.1140/epje/i2011-11095-6]
[Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2011] [Accepted: 07/08/2011] [Indexed: 05/31/2023]
Abstract
Despite two decades of extensive research, direct experimental evidence of a dynamical length scale determining the glass transition of confined polymers has yet to emerge. Using a recently established experimental technique of interface micro-rheology we provide evidence of finite-size effect truncating the growth of a quantity proportional to a dynamical length scale in confined glassy polymers, on cooling towards the glass transition temperature. We show how the interplay of variation of polymer film thickness and this temperature-dependent growing dynamical length scale determines the glass transition temperature, which in our case of 2-3 nm thick films, is reduced significantly as compared to their bulk values.
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