Taiichi Furukawa

Synthesis of functionalized poly(ethylene oxide) macromonomers

Functionalized poly(ethylene oxide) (PEO) macromonomers (α-tertiary amino and ω-methacryloyl groups) were prepared by ring-opening polymerization of living PEO anions using 2-[2-(N,N-dimethylamino)-ethoxy]ethanol potassium alkoxides as an initiator with glycidyl methacrylate. Terminal double bond functionality was controlled in the range of 1–1.5 per molecule in toluene as the hydrocarbon solvent. However, gelation was observed upon such ring-opening polymerization system in tetrahydrofuran solvent. These macromonomers can be applied for the synthesis of peripheral functionalized stars and polymer brushes as the starting materials.

Architecture and solution properties of amphiphilic polymer brushes with peripheral charged ions.

Functionalized poly(ethylene oxide) (PEO) macromonomers (alpha -tertiary amino and omega -methacryloyl groups) were prepared by ring-opening polymerization of live PEO anions end-capped with styrene oxide using 2-[2-(N ,N -dimethylamino)-ethoxy]ethanol potassium alkoxides as an initiator with methacryloyl chloride. PEO brushes were synthesized by free-radical homopolymerization of such PEO macromonomers. These brushes were converted into peripherally charged brushes by quaternization. We studied the solution properties of both types of brushes from the viewpoint of charge effect. It was found from dynamic light scattering (DLS) that the polymer brushes formed a single macromolecule in solution due to crowding of side chains. It was speculated from angular dependence measurements that the polymer brushes with large aspect ratios took a geometrical anisotropic conformation such as a cylinder. In methanol with a low dielectric constant, radius of gyration (R(G)), and cross-sectional radius of gyration (R(G,C)) of the polymer brushes with charged side chains were smaller than those of the polymer brushes without charges. In a solvent with a low dielectric constant such as methanol, ionic groups do not dissociate and condense. On the other hand, these physical values in an aqueous solution were somewhat larger than those of the polymer brushes without charges. In water with a high dielectric constant, peripherally charged brushes were strongly stabilized by electric double layers.