Talreja Manish, Kusaka Isamu, Tomasko David L
William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, 140 West 19th Avenue, Columbus, Ohio 43210, USA.
J Chem Phys. 2009 Feb 28;130(8):084902. doi: 10.1063/1.3077861.
We have used polymer density functional theory to analyze the equilibrium density profiles and interfacial properties of thin films of polymer in the presence of CO(2). Surface tension, surface excess adsorption of CO(2) on polymer surface, and width of the interface are discussed. We have shown the changes in these properties in the presence of CO(2) and with increasing film thickness and their inverse linear relationship with increasing chain length. One of our important findings is the evidence of segregation of end segments toward the interface. We have introduced a new method of representing this phenomenon by means of Delta profiles that show increase in segregation owing to the presence of CO(2) and with increasing chain length. We also make predictions for the octacosane-CO(2) binary system near the critical point of CO(2). Our results indicate qualitative trends that are comparable to the similar experimental and simulation studies.
我们运用聚合物密度泛函理论分析了在二氧化碳存在的情况下聚合物薄膜的平衡密度分布和界面性质。讨论了表面张力、二氧化碳在聚合物表面的表面过量吸附以及界面宽度。我们展示了在二氧化碳存在时、随着薄膜厚度增加这些性质的变化，以及它们与链长增加呈反比的线性关系。我们的一项重要发现是末端链段向界面偏析的证据。我们引入了一种通过δ分布来表示这一现象的新方法，该方法表明由于二氧化碳的存在以及链长的增加，偏析现象增强。我们还对接近二氧化碳临界点的二十八烷 - 二氧化碳二元体系进行了预测。我们的结果表明了定性趋势，这些趋势与类似的实验和模拟研究结果相当。
