[Macromol. Chem. Phys.] Thermoresponsive Poly(2-Oxazoline) Molecular Brushes by Living Ionic Polymerization: Modulation of the Cloud Point by Random and Block Copolymer Pendant Chains
writer：Ning Zhang , Robert Luxenhofer , Rainer Jordan *
keywords：molecular brush, poly(2-oxazoline), LCST
source：期刊
specific source：Macromolecular Chemistry and Physics
Issue time：2012年
Molecular brushes (MBs) of poly(2-oxazoline)s were prepared by living anionic polymerization of 2-isopropenyl-2-oxazoline to form the backbone and living cationic ring-opening polymerization of 2- n -propyl-2-oxazoline and 2-methyl-2-oxazoline to form random and block copolymers. Their aqueous solutions displayed a distinct thermoresponsive behavior as a function of the side-chain composition and sequence. The cloud point (CP) of MBs with random copolymer side chains is a linear function of the hydrophilic monomer content and can be modulated in a wide range. For MBs with block copolymer side chains, it was found that the block sequence had a strong and surprising effect on the CP. While MBs with a distal hydrophobic block had a CP at 70 ° C, MBs with hydrophilic outer blocks already precipitated at 32 ° C.
http://onlinelibrary.wiley.com/doi/10.1002/macp.201200261/abstract