Yanfei
Guo, Huanhuan Liu, Dandan Tang, Cangxia Li, Youliang Zhao*, “Facile synthesis
of silica nanoparticles grafted with quaternized linear, comblike and toothbrushlike
copolymers“, Polym. Chem., 2015, 6, 2647–2658 (DOI: 10.1039/c4py01741b).
http://pubs.rsc.org/en/content/articlelanding/2015/py/c4py01741b
Facile construction of solid substrates grafted
with quaternized copolymers by two step reactions comprising the
alkoxysilane–hydroxyl coupling reaction, quaternization and RAFT polymerization
is described. Silica nanoparticles grafted with poly(N,N-dimethylaminoethyl
methacrylate) (PDMA) were initially prepared via tandem linking reaction and RAFT
polymerization and acted as a versatile platform to generate three types of
ion-bearing topological copolymers grafted silica. Bromide-functionalized
agents and polymers were grafted onto the surface-tethered PDMA backbone to
form quaternized random and comblike copolymers grafted silica, and concurrent
quaternization and RAFT processes were performed to generate silica
nanoparticles grafted with toothbrushlike copolymers comprising poly(methyl
methacrylate), polystyrene, poly(N-isopropylacrylamide) and poly(tert-butyl
acrylate) segments. Free polymers and grafted side chains obtained by a tandem
approach usually have similar chain length and low polydispersity, as evident
from hydrolysis, GPC and 1H NMR analyses. The quaternization efficiency of
graft reactions was in the range of 34–79% (for attaching small molecules) and
3.8–7.4% (for grafting polymeric chains). Our preliminary results revealed that
the surface wettability of hybrid films was dependent on some factors such as
macromolecular architecture, quaternization degree, chemical composition and
temperature. This study affords a straightforward and versatile method to
construct quaternized macromolecular architectures grafted onto hydroxyl-rich
solid substrates, and the resulting silica–polymer hybrids may have a great
potential in stimuli-responsive emulsifiers, surface and antibacterial
materials.