Synthesis of Cylindrical Polymer Brushes with Umbrella-Like
Side Chains via a Combination of Grafting-from and Grafting-onto Methods
- Publication date
- Publisher
Abstract
Cylindrical polymer brushes with
umbrella-like side chains have
been synthesized by a combination of grafting-from and grafting-onto
methods. First, the polymer brushes with azido end-functionalized
poly(<i>tert</i>-butyl acrylate) (P<i>t</i>BA-N<sub>3</sub>) side chains, PBIEM-<i>g</i>-(P<i>t</i>BA-N<sub>3</sub>), were prepared by atom transfer radical polymerization
(ATRP) of <i>t</i>BA monomers using polyinitiator PBIEM
followed by a substitution of bromo-side terminals with sodium azide.
Subsequently, polyamidoamino dendrons of three generations with a
propargyl focal point (G<i>n</i>) were introduced onto the
brush-shaped P<i>t</i>BA-N<sub>3</sub> by copper-catalyzed
azide–alkyne cycloaddition (CuAAC) coupling reaction. The efficiency
of CuAAC between P<i>t</i>BA-N<sub>3</sub> side chains and
G<i>n</i> has showed a dependence on generation number <i>n</i> of the dendrons. At the feed ratio of [G<i>n</i>]:[N<sub>3</sub>] = 1:1, the grafting efficiency of the first generation
dendron (G1) reached above 95%, whereas that of G2 and G3 was at least
84% and 73%, respectively. AFM images indicated that diameter of the
brushes hybridized with G3 increased obviously than that of the brushes
without dendrons