A facile strategy to fabricate covalently linked raspberry-like nanocomposites with pH and thermo tunable structures

Abstract

The preparations of covalently linked raspberry-like composite particles often suffer from uncontrolled particle shape and surface morphology, tedious reactions to introduce surface reactive groups, inefficient inter-particle reactions, and rigorous requirements for the formation of hierarchical structure. In this study, we developed a facile strategy to fabricate a kind of size-controlled, positively charged, alkoxysilanes-functionalized nanoparticles (Tsi-PDMAEMA-PSt NPs) via a combination of the ability of RAFT polymerization to design macromolecular architectures and the process of polymer self-assembly to produce well-defined NPs. Tsi-PDMAEMA-PSt NPs can effectively deposit on the outer surface of negatively charged silica microspheres and then form stable silica@polymer particles by the reaction between alkoxysilanes and surface silanols. The surface morphology, particle size, ζ-potential, structure stability as well as pH and thermo-responsiveness of the prepared composite particles were investigated. The results indicated that the prepared silica@polymer particles possessed unique raspberry-like surface structures with high stability and controllability. Moreover, the surface morphology and dispersion state of silica@polymer particles in water can respond to the change of pH and temperature. Consequently, considering the high simplicity and controllability, the design herein provided a promising route to prepare the long-stable raspberry-like composite microspheres with unique surface morphologies and stimuli-responsive properties for a wide range of possible applications.