Figure 5. Surface morphologies of different coatings after immersion in DMEM with 10% FBS for different time.

(a) HF samples, the surface kept flat during the entire immersion process, unless some white spots observed at day 30; (b) PLLA, with immersion time increasing, gas pockets formed and grew, leading to delamination of the coating; (c) HM/PLLA, within 30 days of immersion, the composite coating kept flat without gas pockets; scale bar represents 1 mm.