Modulation of the effective viscosity of polymer films by ultraviolet ozone treatment

POLYMER

卷:116

Article

Yu, Xuanji^1,2  Beharaj, Anjeza³  Grinstaff, Mark W.³  Tsui, Ophelia K. C.^1,2,4 

[1] Boston Univ, Dept Phys, Boston, MA 02215 USA

[2] Boston Univ, Div Mat Sci & Engn, Boston, MA 02215 USA

[3] Boston Univ, Dept Chem, Boston, MA 02215 USA

[4] Hong Kong Univ Sci & Technol, Dept Phys, Kowloon, Hong Kong, Peoples R China

关键词: Polymer thin films;    Effective viscosity;    Nanoconfinement;    Surface modification;   

DOI  :  10.1016/j.polymer.2017.01.046

来源: Elsevier

【 摘 要 】

Nanoconfinement of a polymer film affords a reduction of the glass transition temperature (Tg) and effective viscosity (heff). Early on, Prof. Tisato Kajiyama pioneered the idea of enhanced polymer mobility at the free surface. This concept is now well established, and accounts for the Tg and heff reductions of thin polymer films. To pay tribute to Prof. Kajiyama's seminal contribution, it is fitting to report in this special issue the use of ultraviolet ozone (UVO) to chemically modify the surface of polymer films and thereby alter their dynamical properties for the first time. Specifically, we show that with a brief exposure time of only 1.0 s under typical UVO treatment conditions, the heff of polystyrene (PS) films supported by silica changes from decreasing to rapidly increasing as the film thickness is decreased upon the UVO treatment. As such, the tendency of the films to spontaneously rupture on heating is significantly lessened. Considering the simplicity and inexpensiveness of the method, our results demonstrate that UVO treatment is an attractive method to refine the dynamical properties of polymer films and improve their thermal stability. (C) 2017 Elsevier Ltd. All rights reserved.

【 授权许可】

Free