Nowadays, biomaterials with amphiphilic properties are undergoing remarkable development. Here, we present one such development, in which we prepared amphiphilic graft copolymers, with a main chain composed of hydroxyethyl acrylamide (HEAA), to introduce hydrophilicity, and a side chain composed of poly(trimethylene carbonate) (PTMC) to introduce tunable hydrophobicity. These macromonomers were created with a novel molecular design, which introduced a ring-opening polymerization by the hydroxyl end group of HEAA in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene, and were analyzed by (1)H NMR and gel permeation chromatography. The amphiphilic graft copolymers were shown to form a hydrogel, the swelling ratio of which was greatly influenced by the number of trimethylene carbonate units. These copolymers also exhibited the Tyndall phenomenon in aqueous solution; they aggregated spontaneously due to hydrogen bonding and hydrophobic interactions, and a sodium 8-anilino-1-naphthalenesulfonate (ANS) fluorescence probe was introduced into the hydrophobic domain. The solution property of ANS in the polymer solution was analyzed by fluorescence measurement and (1)H NMR. The maximum fluorescence wavelength of ANS shifted to shorter wavelengths as the degree of polymerization of the hydrophobic PTMC, the composition of the macromonomer, and the concentration of the copolymer increased. The resulting copolymer formed a polymer micelle structure due to the tunable hydrophobic domain formation in selected solvents. Therefore, these amphiphilic graft copolymers containing a PTMC segment are excellent candidates for use as hydrophobic drug delivery carriers.

New macromonomers based on poly(trimethylene carbonate) (PTMC) were designed and synthesized under precisely controlled conditions using conventional ring-opening polymerization (ROP) techniques. We found that PTMC was connected via the hydroxyl group of N-hydroxyethyl acrylamide (HEAA) or 2-hydroxyethyl acrylate (HEA). However, the preparation of the macromonomers was strongly affected by the concentration of the organic catalyst, inducing unfavorable side reactions. Optimized ROP could be performed by adjusting the concentration of the organic catalyst, 1,8-diazabicyclo[5.4.0]undec-7-ene. The polymerization degree of HEAA-PTMC and HEA-PTMC was maintained in the range of 10 to 50. The reaction was confirmed from the results of 1 H NMR. In this study, we focused on HEAA-PTMC macromonomers. We synthesized the amphiphilic graft copolymer using HEAA and optimal synthetic conditions were proposed.

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