Synthesis of Molecular Brushes with Block Copolymer Side Chains Using Atom Transfer Radical Polymerization

Abstract

Brush macromolecules having poly(n-butyl acrylate-block-styrene) and poly(styrene-blockn-butyl acrylate) side chains have been synthesized by the "grafting from" approach using atom transfer radical polymerization (ATRP). The molecular weights of the resulting polymers were characterized by gel permeation chromatography (GPC) using refractive index and multiangle light scattering detection. The block copolymer side chains were cleaved from the backbone and analyzed by GPC, confirming the synthesis of well-defined copolymer brushes. Visualization of individual molecules by atomic force microscopy (AFM) enabled analysis of the conformation and microstructure of the brush macromolecules on mica surface. The brushes with the pnBuA core were almost fully stretched, while the inverted structure with the pS core exhibited longitudinal contraction compared to the contour length of the main chain. In addition, the poly(n-butyl acrylate-block-styrene) brushes demonstrated a characteristic necklace morphology which was attributed to the interplay between the extension of the pnBuA core and microphase segregation of the pS tails.

Solution Behavior of Temperature‐Responsive Molecular Brushes Prepared by ATRP

“…Due to the wide range of monomers that can be polymerized by ATRP, molecular brushes with interesting solution properties can be envisioned. The synthesis of molecular brushes by grafting from via ATRP have involved the polymerization of acrylate, [15][16][17] methacrylate, [18] and styrenic [15][16][17] monomers.…”

Comb Copolymer Brush with Chemically Different Side Chains

“…20 Using atom transfer radical polymerization, molecular brushes with block copolymer side chains have been prepared as well. 21 The experimental characterization of the comb copolymer brush conformation in dilute solution is a highly nontrivial issue. It was achieved recently by Schmidt and co-workers [21][22][23][24][25][26][27][28] using a combination of light scattering experiments and theoretical modeling.…”

“…21 The experimental characterization of the comb copolymer brush conformation in dilute solution is a highly nontrivial issue. It was achieved recently by Schmidt and co-workers [21][22][23][24][25][26][27][28] using a combination of light scattering experiments and theoretical modeling. Since the high grafting density is supposed to lead to a stiff molecular structure, the modeling has been based on the Kratky-Porod wormlike chain model.…”

Architecture of multi-component copolymer brushes

“…However, the semi-dilute solution properties of cylinder brushes (P2VP block, 33 mol%) showed a clear plateau region in the rheological data, which originated from the entanglement effect. More recently, Matyjaszewski and co-workers [13] have also synthesized diblock copolymer brushes by the 'grafting from' approach, using atom transfer radical polymerization (ATRP).…”