Surface properties of amphiphilic graft copolymer containing different oligo segments

- An amphiphilic graft copolymer composed of hydrophilic and hydrophobic oligo segments was synthesized.
- The hydrophilic or hydrophobic segment was reversibly enriched outermost surface on the polymer membrane.
- This switching behavior was further seen to be a repeatable responsive property.

Two types of novel amphiphilic graft copolymers were synthesized by macromonomer method, and the copolymers were composed of 2-hydroxyethyl acrylate (HEA) or 2-methoxyethyl acrylate (MEA) along with macromonomers with amorphous poly(trimethylene carbonate) (PTMC) and biocompatible poly(ethylene glycol) monomethyl ether (mPEG) segments. The copolymers prepared exhibited low glass transition temperatures, where the mobility of the PTMC segment was high at room temperature. The synthesized polymers were further spin-coated onto a glass substrate, and the polymer-coated surfaces were evaluated using static contact angle measurement. The initial contact angle was influenced by change in the composition ratio of the PTMC macromonomer. However, the wettability of the polymer membrane could be rapidly and reversibly changed from hydrophobic to more hydrophilic upon varying its external environment such as its immersion into different solvents. These results indicated that the copolymer containing PTMC and mPEG segments regulated the surface wettability of its main chain polymer and composition ratio of the macromonomer. This change in wettability most likely occurred due to the mobility of the flexible PTMC segments in the copolymer. Therefore, this copolymer with rapid surface responsiveness has the potential to be used as a surface modifier in biomaterial fields.

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