2.5. Characterization of aligned P(3HO)/P(3HB) blend fibres by SEM

Three separated batches of samples belonging to the three fibre groups with different diameters were characterized using a Philips FEI XL30 Field Emission Gun Scanning Electron Microscope (Philips, Netherlands). Three parameters were analysed: (a) fibre diameter, (b) fibre density, and (c) fibre alignment. An average of 27 fibres per fibre group were studied for the determination of fibre diameter and fibre alignment. The same images used to determine parameters (a) and (c) were analysed to measure the density, which was defined as the number of fibres per unit area of the image. Fibre alignment was determined by measuring the angular variance between the fibres. Therefore, a reference line was drawn parallel to a central fibre, from which the angular difference was measured with respect to each fibre across the sample. The resulting data were collected in four groups classified by their angular difference (±0°, 1°, 2°, and 3°).