371307.fig.004a
(a)
371307.fig.004b
(b)
371307.fig.004c
(c)
Figure 4: SEM micrographs showing the cross-sections of swollen and subsequently freeze-dried PHB films with different PAA nanogel content: (a) PHB; (b) (w/w) PAA; (c) (w/w) PAA.