Anomalous Confinement Slows Surface Fluctuations of Star Polymer Melt Films

被引：13

作者：

Zhang, Fan ^{[1
]}

He, Qiming ^{[1
,4
,5
,6
]}

Zhou, Yang ^{[1
]}

Narayanan, Suresh ^{[3
]}

Wang, Chao ^{[2
]}

Vogt, Bryan D. ^{[2
]}

Foster, Mark D. ^{[1
]}

机构：

[1] Univ Akron, Dept Polymer Sci, Akron, OH 44325 USA

[2] Univ Akron, Dept Polymer Engn, Akron, OH 44325 USA

[3] Argonne Natl Lab, Xray Sci Div, Argonne, IL 60439 USA

[4] Univ Chicago, Inst Mol Engn, Chicago, IL 60637 USA

[5] Argonne Natl Lab, Div Mat Sci, Lemont, IL 60439 USA

[6] Argonne Natl Lab, Inst Mol Engn, Lemont, IL 60439 USA

来源：

ACS MACRO LETTERS | 2018年 / 7卷 / 07期

关键词：

POLYSTYRENE FILMS; THIN; DYNAMICS; CHAIN; ADSORPTION; SUBSTRATE; MECHANISM; SOLIDS; LIMIT;

D O I：

10.1021/acsmacrolett.8b00278

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 unusually large film thickness at which confinement effects manifest themselves in surface fluctuations of unentangled four-arm star polymers has been defined using film thicknesses from 10R(g) to 107R(g). For 15k four-arm star polystyrene (SPS), confinement appears at a thickness between 112 nm (40R(g)) and 72 nm (26R(g)), which is remarkably larger than the thicknesses at which confinement appears for unentangled 6k linear (<15 nm, <7R(g)) and 6k and 14k cyclic (24 and 22 nm, respectively) polystyrenes. Data for 15k star films can be rationalized using a two-layer model with a 17 nm (6R(g)) thick highly viscous layer at the substrate, which is significantly thicker than the 1R(g) thick "irreversibly adsorbed" layer. For a 29 nm (10R(g)) thick film, more striking confinement occurs due to the combined influence of both interfaces. These results underscore the extraordinary role long-chain branching plays in dictating surface fluctuations of thin films.

引用

页码：834 / 839

页数：11

共 30 条

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