2.5.1. Electron Microscopy

The morphologies of the MCM-41 type particles as well as the electrospun PHBV fibers and films were observed by scanning electron microscopy (SEM) using an S-4800 device from Hitachi (Tokyo, Japan). The samples were fixed to beveled holders using conductive double-sided adhesive tape and sputtered with a mixture of gold-palladium under vacuum prior to observation. An accelerating voltage of 10 kV was used. For the cross-section observations, the films were previously cryo-fractured by immersion in liquid nitrogen.

Detailed morphology of the MCM-41 particles and their distribution in the PHBV fibers was further studied by transmission electron microscopy (TEM) using a JEOL 1010 from JEOL USA, Inc. (Peabody, MA, USA) using an accelerating voltage of 100 kV. The estimation of the dimensions was performed by means of the Aperture software from Apple (Cupertino, CA, USA) using a minimum of 20 SEM or TEM micrographs in their original magnification.
