Structure and Ultrasonic Sensitivity of the Superparticles Formed by Self-Assembly of Single Chain Janus Nanoparticles

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• 作者：Feng Zhou ; Mingxiu Xie ; Daoyong Chen
• 刊名：Macromolecules
• 出版年：2014
• 出版时间：January 14, 2014
• 年：2014
• 卷：47
• 期：1
• 页码：365-372
• 全文大小：444K
• ISSN：1520-5835

文摘

Single chain Janus nanoparticles (SCJNPs) (tadpole-like Janus nanoparticles) with a PEO (poly(ethylene oxide)) chain as the 鈥渢ail鈥?and a cross-linked PCEMA (poly(2-cinnamoyloxyethyl methacrylate)) chain as the 鈥渉ead鈥?were synthesized conveniently and efficiently by directly photo-cross-linking PCEMA block of PEO-b-PCEMA diblock copolymer in the common solvent DMF; intramolecular cross-linking occurred dominantly at a relatively high concentration of the copolymer when the cross-linking speed is relatively low, leading to SCJNPs. In selective solvent for the 鈥渢ails鈥? the rigid 鈥渉eads鈥?aggregated into superparticles. It is significant that under a gentle ultrasonic treatment (40 kHz for 10 min) the spherical superparticles formed in DMF/ethanol (1/4, v/v) dissociated into individual SCJNPs. It is also demonstrated that even in pure water in which the superparticles have a more closely aggregated structure, there are still hydrophilic channels within the superparticles connecting the surrounding medium and the inside of the superparticles, which allows rapid transport of hydrophilic small molecules within the superparticles, as demonstrated by the fast acid quench of fluorescence of the encapsulated ANS (8-anilino-1-naphthalenesulfonate). These features should make the superparticles promising in the applications as templates for biomimetic mineralization, highly efficient microreactors for interfacial chemical reactions, and ultrasound responsive nanovehicles for controlled drug release.