Birefringence Control of Semicrystalline Block Copolymers by Crystallization under Confinement

作者：Li Ming Chia; Chang Guang Wei; Lin Tao; Ho Rong Ming^*; Chuang Wei Tsung; Kooi Steven

来源：Langmuir, 2010, 26(22): 17640-17648.

DOI：10.1021/la1034432

A series of semicrystalline block copolymers (BCPs), poly(4-vinylpyridine)-block-poly(epsilon-caprolactone)(P4VP-PCL), with lamellar phases have been synthesized. P4VP-PCL BCP thin films with large-scale, oriented lamellar microdomains were obtained by rimming coating process followed by oscillated shearing using a homemade shear device. Owing to the vitrified P4VP microdomains and strongly segregated microphase separation, specific PCL crystalline chain orientation can be formed from the growth of anisotropic PCL crystallites under confinement so as to uniformly increase the birefringence of the BCP thin films. The enhanced birefringence corresponds well with the increase of PCL crystallinity. Consequently, the birefringence of the P4VP-PCL thin-films can be fine-tuned by PCL crystallization. The variation on the birefringence of the BCP thin films attributed to crystallization and melting is a reversible process with respect to temperature. The BCP thin films can thus he used as temperature-stimulated materials with controllable birefringence via crystallization kinetics.

• 出版日期2010-11-16
• 单位清华大学