ИСТИНА

Poly(3-hydroxybutirate) (PHB) is a semicrystalline biocompatible polymer. In the current work the morphology of ultrathin PHB films was studied by atomic-force microscopy (AFM). The ultrathin films consisted of amorphous drops and semicrystalline lamellae. The crystallization of amorphous drops was visualized at 85C. At higher temperature (125-150C) the crystallization was too fast to be followed by AFM however it was possible to observe the fragmentation of the lamellae and the increase in their height. The obtained data can be explained in terms of relaxation of a metastable film. Upon heating the film adopts the energetically preferable morphology by three interconnected processes: crystallization of the amorphous drops, decrease of the PHB-mica contact area and lamellar thickening.