ma6b01792_si_001.pdf (1.99 MB)
Synthesis of Hybrid Silica Nanoparticles Densely Grafted with Thermo and pH Dual-Responsive Brushes via Surface-Initiated ATRP
journal contribution
posted on 2016-12-15, 09:51 authored by Lei Wu, Ulrich Glebe, Alexander BökerThis work introduces
a synthesis of well-defined thermo and pH
dual-responsive poly(N-isopropylacrylamide)-b-poly(4-vinylpyridine)-grafted
silica nanoparticles (SNPs-g-PNIPAM-b-P4VP) via surface-initiated atom transfer radical polymerization
(ATRP). ATRP initiators were attached onto the surfaces of silica
nanoparticles followed by ATRP of N-isopropylacrylamide
(NIPAM). During the surface-initiated ATRP, free sacrificial initiator
and halogen exchange were utilized to render the polymerization in
a controlled manner. Because of the retention of the polymer chain’s
end-group functionality, chain extension with 4-vinylpyridine
(4VP) from the obtained PNIPAM-grafted SNPs (SNPs-g-PNIPAM) was successfully conducted. Kinetics of the chain extension
was studied in detail, showing the livingness of this reinitiation
process. Subsequent quaternization of the outer P4VP block with methyl
iodide led to the synthesized hybrid nanoparticles being well dispersed
in aqueous solution. This well dispersibility affords the possibility
to study the pH- and thermoresponsive behavior of the diblock copolymer
chains on the nanoparticle surface.