Facile and controllable synthesis of hybrid silica nanoparticles densely grafted with poly(ethylene glycol) |
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| Authors: | Yudan Shui Yunlan Su Xiao Kuang Weiwei Zhao Yuanli Cai Dujin Wang |
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| Affiliation: | 1. Beijing National Laboratory for Molecular Sciences, Key Laboratory of Engineering Plastics, Institute of Chemistry, Chinese Academy of Sciences, China;2. Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, China |
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| Abstract: | We report that a mixture of good and poor solvents greatly enhances the grafting density of nanosized silica grafted with poly(ethylene glycol) (PEG ) by the ‘grafting to’ method. Methoxypolyethylene glycol (MPEG ) (molecular weight 750, 2000 and 4000 g mol?1) was modified in a controlled manner to prepare epoxide terminated PEG (MPEG‐EO ). Silica nanoparticles were modified with N ‐(2‐aminoethy)‐3‐aminopropylmethyldimethoxysilane through the silanization coupling reaction to obtain a well‐defined siloxane structure. MPEG‐EO was coupled to the modified silica by the reaction of their terminal groups in a mixed solvent (n ‐decane/toluene). The grafting density of MPEG‐EO was found to be controlled by the concentration of MPEG‐EO and the ratio of n ‐decane to toluene in the grafting system. Based on TGA , the maximum grafting density was found to be about 2.8, 1.47 and 0.76 chains nm?2 for molecular weights of 750, 2000 and 4000, respectively, which is extremely high compared to previous reports. This high grafting density can be explained by the decreased chain dimension of PEG in the presence of the poor solvent. The method can be applied to other nanoparticles and polymers which can greatly enhance the application of SiO2 nanocomposites. © 2017 Society of Chemical Industry |
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| Keywords: | Stö ber silica nanoparticles poly(ethylene glycol) mixed solvent grafting density grafting to |
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