Controllable Nanostructure Formation through Enthalpy-Driven Assembly of Polyoxometalate Clusters and Block Copolymers

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• 作者：Dan Li ; Xiangmeng Jia ; Xiao Cao ; Tianyang Xu ; Haolong Li ; Hujun Qian ; Lixin Wu
• 刊名：Macromolecules
• 出版年：2015
• 出版时间：June 23, 2015
• 年：2015
• 卷：48
• 期：12
• 页码：4104-4114
• 全文大小：813K
• ISSN：1520-5835

文摘

The coassembly of block copolymers (BCPs) with nanoscale inorganic objects is an important route to fabricate nanostructured polymer composites. However, the immiscibility of inorganic/polymeric interface is a recurring challenge to overcome, particularly for inorganic clusters, such as the polyoxometalates (POMs)/BCPs system. In this paper, we present a general method to incorporate POMs into BCP matrices, in which a POM cluster is embedded as a core in a supramolecular star polymer (SSP) whose arms possess the same chemical composition as a BCP segment. Because of the enthalpic interaction between SSP arms and BCP segments, the SSP can carry POM into BCP matrices to realize their coassembly. By this way, we successfully localize a Keggin-type POM cluster [CoW₁₂O₄₀]^{6鈥?/sup> modified with polystyrene (PS) arms into the PS domain of poly(styrene-b-ethylene oxide) micelles, which induces the formation of a series of hybrid micelles with spherical, toroidal, and bicontinuous structures. The morphological transition of micelles can be adjusted by the length of PS arms and the content of cluster cores. The mechanism is studied by both experimental methods and simulations. An unconventional mechanism for toroid formation is disclosed for the first time, which follows a sphere鈥搑osary鈥搕oroid pathway. Furthermore, the electrostatically bonded structure of SSP is found to play a crucial role on this pathway. These results not only pave the way for fabricating cluster鈥損olymer nanocomposites with controllable structures but also provide new insights into comprehending the self-assembly behavior of complex polymer systems.}