Modulus, confinement, and temperature effects on surface capillary wave dynamics in bilayer polymer films near the glass transition.
Modulus, confinement, and temperature effects on surface capillary wave dynamics in bilayer polymer films near the glass transition.
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模量、限制和温度对玻璃化转变附近双层聚合物薄膜表面毛细波动力学的影响。
DOI：
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发表时间：
2012
影响因子：
8.6
通讯作者：
J. Torkelson
中科院分区：
文献类型：
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作者：
C. M. Evans;S. Narayanan;Zhang Jiang;J. Torkelson
我们报道了用X射线光子相关光谱测量27-127 nm聚苯乙烯(PS)双层膜顶层表面毛细波弛豫时间(τ)。当∼10 °C高于PS玻璃化转变温度(T(G))时，τ以底层模数跟踪，在较软的基板上以低的面内散射波矢显著减小。相对于毛细管波理论，我们还报道了PS层在纳米约束下的硬化行为。在PS T(G)+40 °C时，这两种影响都可以忽略不计。我们演示了相邻的聚合物结构域如何在相当长的尺度上影响动力学。
We report relaxation times (τ) for surface capillary waves on 27-127 nm polystyrene (PS) top layers in bilayer films using x-ray photon correlation spectroscopy. At ∼10 °C above the PS glass transition temperature (T(g)), τ tracks with underlayer modulus, being significantly smaller on softer substrates at low in-plane scattering wave vector. Relative to capillary wave theory, we also report stiffening behavior upon nanoconfinement of the PS layers. At PS T(g)+40 °C, both effects become negligible. We demonstrate how neighboring polymer domains impact dynamics over substantial length scales.