Nanoscale Thermomechanics of Wear-Resilient Polymeric Bilayer Systems
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- 作者：Tassilo Kaule ; Yi Zhang ; Sebastian Emmerling ; Sascha Pihan ; Renate Foerch ; Jochen Gutmann ; Hans-J眉rgen Butt ; R眉diger Berger ; Urs Duerig ; Armin W. Knoll
- 刊名：ACS Nano
- 出版年：2013
- 出版时间：January 22, 2013
- 年：2013
- 卷：7
- 期：1
- 页码：748-759
- 全文大小：696K
- 年卷期：v.7,no.1(January 22, 2013)
- ISSN：1936-086X
文摘
We explore the effect of an ultrathin elastic coating to optimize the mechanical stability of an underlying polymer film for nanoscale applications. The coating consists of a several nanometer thin plasma-polymerized norbornene layer. Scanning probes are used to characterize the system in terms of shear-force-induced wear and thermally assisted indentation. The layer transforms a weakly performing polystyrene film into a highly wear-resistive system, ideal for high-density and low-power data storage applications. The result can be understood from the indentation characteristics with a hot and sharp indenter tip. The latter gives rise to a deformation mode in the fully plastic regime, enabling a simple interpretation of the results. The softening transition and the yield stress of the system on a microsecond time scale and a nanometer size scale were obtained. We show that the plastic deformation is governed by yielding in the polystyrene sublayer, which renders the overall system soft for plastic deformation. The ultrathin protection layer contributes as an elastic skin, which shields part of the temperature and pressure and enables the high wear resistance against lateral forces. Moreover, the method of probing polymers at microsecond and nanometer size scales opens up new opportunities for studying polymer physics in a largely unexplored regime. Thus, we find softening temperatures of more than 100 掳C above the polystyrene glass transition, which implies that for the short interaction time scales the glassy state of the polymer is preserved up to this temperature.