Photo-Cross-Linked Diblock Copolymer Micelles: Quantitative Study of Photochemical Efficiency, Micelles Morphologies and their Thermal Behavior

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• 作者：Dao L锚 ; Livie Li茅nafa ; Trang N. T. Phan ; Damien Deleruyelle ; Renaud Bouchet ; S茅bastien Maria ; Denis Bertin ; Didier Gigmes
• 刊名：Macromolecules
• 出版年：2014
• 出版时间：April 8, 2014
• 年：2014
• 卷：47
• 期：7
• 页码：2420-2429
• 全文大小：517K
• 年卷期：v.47,no.7(April 8, 2014)
• ISSN：1520-5835

文摘

Amphiphilic block copolymers based on azido-functional polystyrene (PVBA) and hydrophilic poly(ethylene oxide) (PEO) have been synthesized by nitroxide mediated polymerization and used to prepare aqueous spherical micelles. These micelles consisting of a PEO corona and a PVBA core were stabilized by cores cross-linking under UV irradiation without addition of photoreagent. The efficiency of the core cross-linking was estimated in term of the conversion of azide groups to dibenzyldiazene junctions with liberation of gaseous nitrogen molecules. The micellar structures were studied by dynamic light scattering (DLS) and atomic force microscopy (AFM). Differential scanning calorimetry (DSC) was used to characterize the thermal behavior of freeze-dried micelles. Attachment of PEO block to a rigid core modified considerably the thermal behavior of PEO. We observed a decrease of about 15 掳C for the crystallization temperature and 50% for the degree of crystallinity of cross-linked micelles submitted to 45 min UV irradiation compared to pristine copolymer.