An attempt to separate roughness from interdiffusion in the interfacial broadening between two immiscible polymers
An attempt to separate roughness from interdiffusion in the interfacial broadening between two immiscible polymers
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DOI：
10.1021/ma990306u
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发表时间：
2000-03
期刊：
影响因子：
5.5
通讯作者：
V. Stone;R. Legras;X. Arys;A. Jonas
中科院分区：
文献类型：
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作者：
V. Stone;R. Legras;X. Arys;A. Jonas
用X射线反射法（XRR）和X射线漫散射法（XDS）对聚苯乙烯（PS）和氯化聚丁二烯（CPB）在150 ℃下的界面形成过程进行了详细的研究。通过XRR测定平衡熔体界面宽度σ（m）（150 ℃）= 18.8 +/-0.3埃。在该方法中，在相干区域上平均的横向波动a必须被认为源自均聚物相互扩散（σ（CPB/PS））和界面粗糙度（σ（r））：σ（m）（2）= σ（CPB/PS）（2）+ σ（r）（2）。在文献中，界面粗糙度通常被描述为由于样品制备的残余粗糙度（假设1）或在界面处建立的毛细管波动（假设2）。的性质和重要性的界面粗糙度进行评估，XDS扫描，其中包括检测所产生的横向相关性的粗糙度分布的漫（离镜面）散射。虽然假设1可以明确拒绝从我们的XDS数据的分析，至少有两个同样有价值的理论拟合数据被发现在退火过程中的界面粗糙度变化的假设。在第一种情况下，相互扩散受到限制，并且界面宽度由粗糙度决定（σ（r）> σ（CPB/PS））。在第二种情况下，情况正好相反：sigma（CPB/PS）远大于sigma（r）。前者的图片是更接近现有的毛细作用的分子理论的预测，并通过平均场参数计算的Flory-Huggins相互作用参数给出了一个更好的协议从CPB和PS的溶解度参数获得的相互作用参数。
A detailed study of the interface formation between polystyrene (PS) and chlorinated polybutadiene (CPB) at 150 degrees C is carried out on bilayer samples by X-ray reflectometry(XRR) and X-ray diffuse scattering (XDS). An equilibrium melt interfacial width sigma(m)(150 degrees C) = 18.8 +/- 0.3 Angstrom is determined by XRR. Lateral fluctuations being averaged over the coherence area in this method, a, must be considered as originating from both homopolymer interdiffusion (sigma(CPB/PS)) and interfacial roughness (sigma(r)): sigma(m)(2) = sigma(CPB/PS)(2) + sigma(r)(2). Interfacial roughness is generally described in the literature to be due to either a residual roughness from sample preparation (hypothesis 1) or capillary fluctuations building up at the interface (hypothesis 2). The nature and importance of the interfacial roughness are assessed by XDS scans, which include the detection of the diffuse (off-specular) scattering arising from lateral correlations in the roughness profile. While hypothesis 1 can be unambiguously rejected from the analysis of our XDS data, at least two equally valuable fits of theory to data are found under the hypothesis that the interfacial roughness changes during annealing. In the first one, interdiffusion is restricted, and the interfacial width is dominated by roughness (sigma(r) > sigma(CPB/PS)). In the second one, the reverse is true: sigma(CPB/PS) much greater than sigma(r). The former picture is closer to predictions from existing molecular theories of capillarity and gives for the Flory-Huggins interaction parameter computed through mean-field arguments a better agreement with the interaction parameter obtained from solubility parameters of CPB and PS.