Preparation of oligoamide-ended poly(ethylene glycol) and hydrogen-bonding-assisted formation of aggregates and nanoscale fibers

An oligoamide-ended poly(ethylene glycol) (PEG) with a PEG weight-average molecular weight of 5000 (PEG-5000-oligoamide), with 3,5-bis-[2-(5-acetylamino- 2-isobutoxy-benzoylamino)-acetylamino]-benzoyl as the oligoamide, was synthesized. PEG-5000-oligoamide aggregated in chloroform or toluene via hydrogen-bonding interactions among the oligoamide strands as a core and PEG, which was soluble in the solvents, as a shell. When a chloroform solution of PEG-5000-oligoamide at a concentration of approximately 0.06 g/L was cast onto a silicon wafer or a mica plate, rapid solvent evaporation induced its self reassembly as nanonbers.