*2.4. Phase Diagram*

The sol–gel transition phase diagram of mPEG-PELG solutions was measured by the tube inversion method. The copolymer was dissolved using phosphate-buffered saline (PBS, 0.01 M, pH 7.4) at a given concentration in test tube with an inner diameter of 11 mm, and stirred at 0 ◦C for 72 h. The sol–gel status of the solution was observed with increasing the temperature at a rate of 2 ◦C per 10 min. The gelation temperature was determined when the solution kept no flow within 30 s after inverting the test tube.
