Figure 1. Characterization of PDLLA-PEG-PDLLA micelle at low concentrations and schematic diagram showing the thermogelling behavior.

(A,B) TEM image and particle size of micelles at 25 °C (S3, 0.1 wt%). (C,D) Particles size distribution spectrum of micelles (S3, 1 wt% and 10 wt%) at different temperatures, each measurement performed after an equilibration for 10 min. (E) The schematic diagram of the process of temperature-induced physical gelation. The amphiphilic block copolymers self-assemble into core-shell-like micelles in aqueous solution (25 wt%) and then gelate between room temperature and body temperature due to the augment and aggregation of the micelles after heating.