Crystallization Behavior of Poly(蔚-caprolactone) Chains Confined in Nanocylinders: Effects of Block Chains Tethered to Nanocylinder Interfaces

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• 作者：Shintaro Nakagawa ; Takumi Tanaka ; Takashi Ishizone ; Shuichi Nojima ; Yasuhiko Kakiuchi ; Kazuo Yamaguchi ; Seiichi Nakahama
• 刊名：Macromolecules
• 出版年：2013
• 出版时间：March 26, 2013
• 年：2013
• 卷：46
• 期：6
• 页码：2199-2205
• 全文大小：373K
• 年卷期：v.46,no.6(March 26, 2013)
• ISSN：1520-5835

文摘

The crystallization behavior of poly(蔚-caprolactone) (PCL) chains (i.e., PCL block + PCL homopolymer systems) spatially confined in nanocylinders with different diameters D has been investigated as a function of the mole fraction of PCL homopolymers f_homo existing in the PCL chains. The nanocylinders with PCL chains inside were prepared using the microphase separation of PCL-block-polystyrene (PCL-b-PS) diblock copolymers with a photocleavable o-nitrobenzyl group (ONB) between PCL and PS blocks, and subsequently ONB was cleaved by a controlled irradiation of UV light to get the PCL chains with various f_homo. In the isothermal crystallization process, the crystallinity of PCL chains showed an exponential time evolution (or first-order kinetics) for all the systems investigated. The half-time of crystallization of PCL chains with 0 < f_homo < 1 was found to be intermediate between those of PCL blocks (f_homo = 0) and PCL homopolymers (f_homo 1); it decreased moderately with increasing f_homo in a smaller nanocylinder (D 14.9 nm) but increased slightly in a larger nanocylinder (D 17.2 nm). We discussed the effects of tethered PCL blocks on the crystallization mechanism of PCL chains confined in nanocylinders on the basis of a general theory for polymer nucleation.