Affinity of Polystyrene Films to Hydrogen-Passivated Silicon and Its Relevance to the Tg of the Films
Affinity of Polystyrene Films to Hydrogen-Passivated Silicon and Its Relevance to the Tg of the Films
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DOI：
10.1021/ma901851w
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发表时间：
2009-10-13
期刊：
影响因子：
5.5
通讯作者：
Tsui, Ophelia K. C.
中科院分区：
文献类型：
--
作者：
Fujii, Yoshihisa;Yang, Zhaohui;Tsui, Ophelia K. C.
在氢钝化硅 (H-Si) 支撑的聚苯乙烯 (PS) 薄膜的玻璃化转变温度 T-g 中观察到了不同的厚度依赖性。有人建议，在空气中高温退火时，这些薄膜的聚合物/基底界面（即PS/Si）虽然埋在PS层下面，但可能会被氧化，使薄膜呈现不同的聚合物/基底界面（即PS/SiOx-Si），这可能解释了观察到的T-g的不同厚度依赖性。在本实验中，我们检查 PS/H-Si 薄膜的埋入衬底界面是否确实可以通过在空气中 150 摄氏度下退火来氧化。我们的结果表明，H-Si 表面上确实形成了一层残留膜，但它是 PS 的结合层。 X 射线光电子能谱 (XPS) 分析以及残余膜油与初始 PS 厚度的独立性证明，埋在 PS 膜下方的 H-Si 衬底不会因退火而氧化。我们讨论了如何在这些薄膜的 T-g 中观察到不同厚度依赖性的可能解释。
Qualitatively different thickness dependences have been observed in the glass transition temperature, T-g of polystyrene (PS) films supported by hydrogen-passivated silicon (H-Si). It has been suggested that upon annealing at high temperatures in air, the polymer/substrate interface of these films (i.e., PS/Si), though buried underneath the PS layer, might be oxidized, rendering the films a different polymer/ substrate interface (i.e., PS/SiOx-Si), which may account for the different thickness dependences of the T-g observed. In this experiment, we examine if the buried Substrate interface of PS/H-Si films can indeed be oxidized by annealing the films at 150 degrees C in air. Our result shows that a residual film does form on top of the H-Si surface, but it is a bound layer of PS. X-ray photoelectron spectroscopic (XPS) analyses and independence of the residual film oil the initial PS thickness evidence that the H-Si substrate buried underneath a PS film is not oxidized by annealing. We discuss a possible explanation to how the different thickness dependences may be observed in the T-g of these films.