Fig. 2. Domain orientations of HA scaffolds fabricated under different cooling rates (1, 5, and 10°C/min) and using PDMS wedges with various slope angles (α ≈ 0°, 5°, 10°, and 20°).

All the samples were prepared from a 20 volume % HA slurry. SEM images show the scaffold cross sections parallel to the cold finger. Each domain, delimited by a given orientation, was labeled with artificial colors. Insets: For every image, the Fourier transform indicates the alignment of global domains. (A to D) At the lowest cooling rate (1°C/min), no obvious large-scale aligned lamellar structure was observed regardless of the slope angle. (E to L) At higher cooling rates of 5 (E to H) and 10°C/min (I to L), domains appeared to become more aligned with increasing slope angle. For slope angles of 10° and 20°, a large single domain can be observed across the whole sample length.