Fig. 4

Calcite crystals precipitated in the presence of PGMA and 14 nm PGMA-NPs. a Optical micrograph of crystals grown in the presence of 1 wt% PGMA polymer only. b–h Analyses of crystals precipitated in the presence of 0.05 wt% of PGMA-NPs. b Optical micrograph, c SEM image of FIB cross-section and d STEM HAADF image of a lamellar cut from a crystal. e Segmented STEM tomograms of a sectioned lamella from a representative crystal shown perpendicular to the lamella and at two angles. f A low-magnification TEM image of a sectioned lamella from a crystal and the corresponding selected area electron diffraction (SAED) pattern, recorded off the zone axis, to enable diffraction rings from the gold NPs to be readily observed. Two further SAED patterns from the areas indicated are also shown, demonstrating the single crystal structure. g Single crystal diffraction pattern (recorded with a single crystal diffractometer) taken from a crystal ≈70 μm in size. The reconstructed (unwarped) layer of the diffraction pattern along the [0 0 1] direction is shown, where this was obtained by full rotations of the crystal. h Lab powder XRD diffractograms of PGMA-NP/calcite nanocomposite crystals containing 4 and 14 nm NPs.