Figure 20.

Demonstration by Xu et al. ²⁴⁴ of the formation of CaCO₃ films under porphyrin-based Langmuir monolayers. (a) Schematic depicting the template-inhibitor approach to formation of oriented calcite films deposited under Langmuir monolayers. (b) SEM of the CaCO₃ films, with one piece of film placed on top of another to provide a view of the two different sides of the film simultaneously. The smooth side was facing the template and the rough and particulate side was facing the subphase. The inset shows the rough side at higher magnification. (c) Calcite crystal nucleated on the same porphyrin monolayer, but without addition of polymeric inhibitor. The crystal orientation was the same as the CaCO₃ films shown in (b), but the crystal grew into solution with a faceted 3D morphology since it was formed via the conventional nucleation and growth process. (a & b) (Reprinted with permission from ref 244. Copyright 1998 American Chemical Society.) (c) (Reprinted with permission from ref 115. Copyright 1997 American Chemical Society.)