A Simple Route To Improve Inorganic Nanoparticles Loading Efficiency in Block Copolymer Micelles

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• 作者：Weikun Li ; Shanqin Liu ; Renhua Deng ; Jianying Wang ; Zhihong Nie ; Jintao Zhu
• 刊名：Macromolecules
• 出版年：2013
• 出版时间：March 26, 2013
• 年：2013
• 卷：46
• 期：6
• 页码：2282-2291
• 全文大小：734K
• 年卷期：v.46,no.6(March 26, 2013)
• ISSN：1520-5835

文摘

The formation of well-defined polymer/inorganic nanoparticles (NPs) hybrid micelles with high loading of the NPs is critical to the development of nanomaterials with desired optical, electric, magnetic, and mechanical properties. Herein, we introduce a simple strategy to encapsulate monodisperse polystyrene (PS)-grafted Au NPs into the PS core of PS-b-poly(4-vinylpyridine) (PS-b-PVP) micelles through block copolymer (BCP)-based supramolecular assembly. We demonstrate that selective incorporation of gold NPs into the PS cores during the assembly process can induce the formation of well-ordered hybrid micelles with spherical, cylindrical, or nanosheet morphologies. The number of NPs in each micelle can be effectively increased by simply increasing the content of NPs and adjusting the ratio of 3-n-pentadecylphenol (PDP) to the P4VP units accordingly. The balance between the NP loading (increasing the volume fraction of PS domain) and the PDP addition (increasing the volume fraction of PVP(PDP) domain) maintains the same micellar morphology while achieving high NP loading. Moreover, strong enthalphic attraction of H-bonding between PDP and P4VP can increase the effective interaction parameter of the system to maintain the strong segregation, leading to the formation of ordered structures. The mass density of NPs in the hybrid micelles was further enhanced after removal of the added PDP from the supramolecules. No macrophase separation or order鈥搊rder morphological transition was observed even when the volume fraction of PS-grafted NPs (蠁_NP-M) in the hybrid micelles reached 84.1 vol % (or 68 wt % on the ligand free NPs basis). Furthermore, we show that ordered clusters of NPs were generated within the spherical micelles when the 蠁_NP-M reached 72.5 vol %. This directed supramolecular assembly provides an easy means to tailor the interactions between BCPs and NPs, thus generating ordered structures which can only be achieved when the loading of NPs is high enough. This approach is versatile and applicable to different types of NPs and different micellar aggregates and supramolecular pairs. It offers a new route for preparing hybrids with applications in the fields of molecular electronic devices, high-density data storage, nanomedicine, and biosensors.