Levicky R, Koneripalli N, Tirrell M, Ankner JF, Kaiser H, Satija SK
NIST Center for Neutron Research, Gaithersburg, Maryland 20899.
Macromolecules. 1998 Jul 28;31(15):4908-14. doi: 10.1021/ma9716185.
Compositional variation in blends of triblock and diblock copolymer films can be used to adjust the film response to a selective solvent. We investigated the relationship between blend composition and film structure in ordered films containing poly(styrene-b-2-vinylpyridine) (PS-P2VP) diblocks and PS-P2VP-PS triblocks. The study focuses on films possessing a lamellar morphology. Methanol, a strongly selective solvent for P2VP, is used to swell the films. Since methanol solvates P2VP but not PS, periodic multilayer structures result in which solvent-rich P2VP domains are separated by undissolved PS domains. The film structure is characterized in the dry and swollen states with neutron reflectivity. Although the dry state morphology dimensions are practically identical for all samples, in the swollen state films richer in triblock swell less due to higher density of bridges interconnecting the PS domains. Furthermore, in swollen triblock-containing samples, polymer concentration variations in P2VP domains are suppressed and the PS domains are better aligned with respect to the substrate.
三嵌段和二嵌段共聚物薄膜共混物的组成变化可用于调节薄膜对选择性溶剂的响应。我们研究了含有聚（苯乙烯-b-2-乙烯基吡啶）（PS-P2VP）二嵌段和PS-P2VP-PS三嵌段的有序薄膜中，共混物组成与薄膜结构之间的关系。该研究聚焦于具有层状形态的薄膜。甲醇是P2VP的强选择性溶剂，用于使薄膜溶胀。由于甲醇能溶剂化P2VP而不能溶剂化PS，因此形成了周期性的多层结构，其中富含溶剂的P2VP域被未溶解的PS域隔开。用中子反射率对干燥和溶胀状态下的薄膜结构进行表征。尽管所有样品的干燥状态形态尺寸实际上相同，但在溶胀状态下，由于连接PS域的桥密度较高，富含三嵌段的薄膜溶胀较小。此外，在含有三嵌段的溶胀样品中，P2VP域中的聚合物浓度变化受到抑制，并且PS域相对于基底的排列更好。
