Fig. 7.

TEM and optical micrographs of calcite crystals precipitated in the presence of 4 nm PGMA-NPs. a Low-magnification bright field TEM image of an FIB-cross-sectioned calcite lamella showing the areas from which the selected area electron diffraction patterns (SAED) were taken. b STEM HAADF EDX mapping showing the homogeneous distribution of Ca and Au. c Corresponding SAED patterns demonstrate that single crystallinity is maintained throughout the crystal shown in a. d Off-zone axis SAED pattern showing rings corresponding to gold, which matches with diffraction pattern of Au NPs alone. e–g Optical micrographs of calcite crystals grown at concentrations e 0.001 wt%, f 0.005 wt%, and g 0.02 wt% 4 nm PGMA-NPs.