Traiphol Rakchart
Department of Chemistry, Faculty of Science, Naresuan University, Phitsanulok 65000, Thailand.
J Colloid Interface Sci. 2007 Jun 1;310(1):217-28. doi: 10.1016/j.jcis.2007.01.027. Epub 2007 Jan 19.
This study compares the stability of various polymeric thin films supported on SiO(x)/Si substrate. Dewetting behaviors of polystyrenes (PS), polychloromethylstyrenes, and random poly(styrene-co-chloromethylstyrene)s are investigated by utilizing atomic force microscopy. A systematic addition of the chloromethylstyrene (ClMS) unit into PS chain causes the increase of segment polarity, affecting interfacial and interchain interactions in thin films. It is found that stability of the polymeric films depends on two major parameters, ratio of the ClMS unit and film thickness. For approximately 5 nm thick film, the addition of only 5 mol% ClMS unit causes a drastic increase of its stability, attributed to the enhanced interfacial interactions between ClMS group and SiO(x) layer. Further increasing the ClMS mole ratio to 20, 45, and 100% is accompanied by a systematic increase of the film stability. Thicker films (thicknesses approximately 22 and approximately 45 nm) of the copolymer with 5 mol% ClMS unit exhibit rather different behavior. They are found to be less stable compared to the PS films. However, the films of copolymers with ClMS unit of 20, 45, and 100% are still much more stable than the PS films. These dewetting behaviors of the copolymers are correlated to the interfacial interactions, interchain interactions and segmental segregation in thin films.
本研究比较了负载在SiO(x)/Si衬底上的各种聚合物薄膜的稳定性。利用原子力显微镜研究了聚苯乙烯（PS）、聚氯甲基苯乙烯和无规聚（苯乙烯-共-氯甲基苯乙烯）的去湿行为。向PS链中系统地添加氯甲基苯乙烯（ClMS）单元会导致链段极性增加，从而影响薄膜中的界面和链间相互作用。研究发现，聚合物薄膜的稳定性取决于两个主要参数，即ClMS单元的比例和薄膜厚度。对于厚度约为5 nm的薄膜，仅添加5 mol%的ClMS单元会使其稳定性急剧增加，这归因于ClMS基团与SiO(x)层之间增强的界面相互作用。将ClMS摩尔比进一步提高到20%、45%和100%时，薄膜稳定性会系统性增加。含5 mol% ClMS单元的共聚物制成的较厚薄膜（厚度约为22 nm和约45 nm）表现出相当不同的行为。发现它们与PS薄膜相比稳定性较差。然而，含20%、45%和100% ClMS单元的共聚物薄膜仍然比PS薄膜稳定得多。这些共聚物的去湿行为与薄膜中的界面相互作用、链间相互作用和链段偏析相关。
