Phosphonic Acid-Functionalized Diblock Copolymer Nano-Objects via Polymerization-Induced Self-Assembly: Synthesis, Characterization, and Occlusion into Calcite Crystals

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• 作者：Andreas Hanisch ; Pengcheng Yang ; Alexander N. Kulak ; Lee A. Fielding ; Fiona C. Meldrum ; Steven P. Armes
• 刊名：Macromolecules
• 出版年：2016
• 出版时间：January 12, 2016
• 年：2016
• 卷：49
• 期：1
• 页码：192-204
• 全文大小：895K
• ISSN：1520-5835

文摘

Dialkylphosphonate-functionalized and phosphonic acid-functionalized macromolecular chain transfer agents (macro-CTAs) are utilized for the reversible addition–fragmentation chain transfer (RAFT) dispersion polymerization of benzyl methacrylate (BzMA) at 20% w/w solids in methanol at 64 °C. Spherical, worm-like, and vesicular nano-objects could each be generated through systematic variation of the mean degree of polymerization of the core-forming PBzMA block when using relatively short macro-CTAs. Construction of detailed phase diagrams is essential for the reproducible targeting of pure copolymer morphologies, which were characterized using transmission electron microscopy (TEM) and dynamic light scattering (DLS). For nano-objects prepared using the phosphonic acid-based macro-CTA, transfer from methanol to water leads to the development of anionic surface charge as a result of ionization of the stabilizer chains, but this does not adversely affect the copolymer morphology. Given the well-known strong affinity of phosphonic acid for calcium ions, selected nano-objects were evaluated for their in situ occlusion within growing CaCO₃ crystals. Scanning electron microscopy (SEM) studies provide compelling evidence for the occlusion of both worm-like and vesicular phosphonic acid-based nano-objects and hence the production of a series of interesting new organic–inorganic nanocomposites.