Order-Order Transition (OOT) in ABC Triblock Copolymer Thin Film Induced in Solvent vapor

摘要

The power of using a triblock copolymer when compared to a traditional diblock copolymer is evidenced by the ability to exploit and combine the advantages of two separate diblock copolymer systems. For example, Russell and co-workers 1reported the synthesis and the self-assembly of a very useful ABC triblock copolymer induced in neutral solvent vapor and have obtained defect-free nanoporous thin films. Up to our knowledge, many thin-film studies on the well-ordered morphology of ABC triblock copolymer induced in the solvent vapor have focused on the utility of the good solvent vapor.2-10In some diblock copolymer thin films, the well-ordered morphologies can be observed induced in the strongly selective solvent vapor. 11 Though not in equilibrium, such structures may be of particular interest as they significantly increase the number of patterns to be created by a given polymer. How is the effect of solvent selectivity on the morphologies of ABC triblock copolymer thin films? Here, we study the morphology evolution of ABC thin film induced both in saturated good solvent vapor, which shows slight selectivity to A block, and in saturated strongly selective solvent vapor for two end blocks at room temperature. Two different order-order-transition (OOT) processes could be presented.