Crystallization and Morphology of Autophobic Dewetted Poly（ε-caprolactone）-b-poly（L-lactide） Diblock Copolymer Ultrathin Films  

作　　者：严德荣 黄海瑛 何天白 

机构地区：[1]State Key Laboratory of Polymer Physics and Chemistry,Changchun Institute of Applied Chemistry,Chinese Aead-emy of Sciences,Graduate School of Chinese Academy of Sciences Changchun,Jilin 130022,China

出　　处：《Chinese Journal of Chemistry》2012年第9期2198-2204,共7页中国化学（英文版）

摘　　要：We have investigated the crystallization and morphological behaviors of poly（ε-caprolactone）-b-poly（L-lactide） （PCL-b-PLLA） in its autophobic dewetted ultrathin films （-11 nm） using atomic force microscopy （AFM） and transmission electron microscopy （TEM）. The autophobic dewetting process creates a well defined film geometry containing an extremely thin wetting layer （-4.5 nm） with densely distributed micrometer droplets atop, which re- stricts the primary nucleation process to occurring only in the droplets. In addition to the normally encountered flat-on lamellae, the growth of edge-on lamellae in such a thin wetting layer has been observed on both of two crys- tallization paths. In thermal crystallization, flat-on lamellae are favored at small supercoolings while edge-on la- mellae appear at very large supercoolings both in the droplets and the wetting layer. For cold crystallization, the edge-on lamellae can form easily in the droplets and grow into the wetting layer even at very small supercoolings. These observations are explained on the basis that the nucleation and lamellar orientation are strongly affected by the film geometry, the crystallization paths, and the applied supercoolings.We have investigated the crystallization and morphological behaviors of poly（ε-caprolactone）-b-poly（L-lactide） （PCL-b-PLLA） in its autophobic dewetted ultrathin films （-11 nm） using atomic force microscopy （AFM） and transmission electron microscopy （TEM）. The autophobic dewetting process creates a well defined film geometry containing an extremely thin wetting layer （-4.5 nm） with densely distributed micrometer droplets atop, which re- stricts the primary nucleation process to occurring only in the droplets. In addition to the normally encountered flat-on lamellae, the growth of edge-on lamellae in such a thin wetting layer has been observed on both of two crys- tallization paths. In thermal crystallization, flat-on lamellae are favored at small supercoolings while edge-on la- mellae appear at very large supercoolings both in the droplets and the wetting layer. For cold crystallization, the edge-on lamellae can form easily in the droplets and grow into the wetting layer even at very small supercoolings. These observations are explained on the basis that the nucleation and lamellar orientation are strongly affected by the film geometry, the crystallization paths, and the applied supercoolings.

关 键 词：CRYSTALLIZATION autophobic dewetting poly（ε-caprolactone）-b-poly（L-lactide） ultrathin film 

分 类 号：TQ131.13[化学工程—无机化工] O484.1[理学—固体物理]