Controlled synthesis of polymethylene-b-poly(ethylene glycol) as well as its crystallization and self-assembly behavior

Abstract

Polymethylene-b-poly(ethylene glycol) (PM-b-PEG) with different block length ratio was synthesized by a combination of polyhomologation and coupling reaction. The effect of hydrophilic and hydrophobic block length on the crystallization process and self-assembly behavior of PM-b-PEG was self-assembled were investigated. The results showed that with the increase of methylene units, the crystallization temperature of PM block raised from 54.59 °C to 70.93 °C gradually, while that of the PEG block reduced from 17.54 °C to 15.23 °C. In addition, the amphiphilic PM-b-PEG was self-assembled into star-like micelles in water, and its diameter extended from 98.2 nm to 151.9 nm as the block length of hydrophobic PM increased from 30 to 70. And the micelles also exhibit super stability when the concentration of copolymer precursor is 0.50 ∼ 0.90 mg/ml and the storage temperature lies in the range of 25 ∼ 60 °C.