Effect of Confinement on Structural Relaxation in Ultrathin Polymer Films Investigated by Local Dielectric Spectroscopy

被引：39

作者：

Nguyen, Hung K. ^{[2
]}

Prevosto, Daniele ^{[1
]}

Labardi, Massimiliano ^{[1
]}

Capaccioli, Simone ^{[1
,2
]}

Lucchesi, Mauro ^{[1
,2
]}

Rolla, Pierangelo ^{[1
,2
]}

机构：

[1] CNR IPCF, Dip Fis Largo Pontecorvo 3, I-56127 Pisa, Italy

[2] Univ Pisa, Dipartimento Fis Enrico Fermi, I-56127 Pisa, Italy

来源：

MACROMOLECULES | 2011年 / 44卷 / 16期

关键词：

GLASS-TRANSITION; DYNAMICS; MOBILITY; MICROSCOPY; LAYERS;

D O I：

10.1021/ma200440z

中图分类号：

O63 [高分子化学（高聚物）];

学科分类号：

070305 ; 080501 ; 081704 ;

摘要：

The effect of confinement on structural relaxation in ultrathin poly(vinyl acetate) films has been studied by local dielectric spectroscopy. This scanning probe method allows the investigation of dielectric relaxation at nanometer scale of supported ultrathin films having a free surface. Measurements have been performed at ambient pressure and controlled atmosphere on films with decreasing thickness. A deviation of dynamic properties from the bulk behavior, showing up as an increase of the relaxation rate, was observed starting from film thickness of 35 nm, which corresponds to about 3 times the gyration radius of polymer chains. A 2-fold increase of relaxation rate was measured for the thinnest investigated film of 18 nm. Local dielectric spectroscopy is therefore an effective method to elucidate confinement effects on relaxation dynamics in ultrathin polymer films with a free upper surface.

引用

页码：6588 / 6593

页数：6

共 32 条

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