Facile synthesis of thermo-responsive nanogels less than 50 nm in diameter via soap- and heat-free precipitation polymerization
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Owing to their highly desirable properties that combine the properties of both hydrogels and nanomaterials, smart nanogels own great potentials as active nanocarriers in medical applications. In this paper, thermo-responsive nanogels with uniform sizes less than 50 nm in diameter were synthesized using potassium persulfate (KPS)/N,N,N′,N′-tetramethylethylenediamine (TMEDA) as a initiator system via a facile surfactant-free precipitation radical polymerization of N-isopropylacrylamide (NIPAM) at room temperature. Both transmission electron microscopy and dynamic light scattering were used to characterize the morphologies and diameters of the PNIPAM nanogels. All nanogels with spherical shape exhibited a narrow size distribution, and the finest nanogels were 43 nm in diameter on average. The very fine and highly pure nanogels would be more promising for drug delivery carriers than the bulk gels or microgels.
This work is financially supported by the National Natural Science Foundation of China (No. 31370568), Opening Project from CAS Key Laboratory of Engineering Plastics, Institute of Chemistry (China), Public Welfare Projects of Zhejiang Province (No. 2017C33113), and Scientific Research Foundation of Zhejiang Agriculture and Forestry University (No. 2013FR088).
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Conflict of interest
The authors declare that they have no conflict of interest.
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