Using a Langmuir-Blodgett film of dipalmitoylphosphatidylcholine(DPPC), a model of biomembranes, as a template, we succeed in obtaining oriented KH 2PO 4(KDP) crystals toward crystal face (100) under well-compressed DPPC monolayer. This is explicable in terms of the geometrical complementarity between KDP and the DPPC monolayer. It is found that the distances between the closest K-K (0.416 nm) fit the d(100) network spacing of DPPC monolayer(0.420 nm), which results in that the special activation energy for nucleation exists in the interface covered with DPPC monolayer. DPPC monolayer has a very strong selected catalysis on the crystallization of KDP crystal face (100), and drives KDP rapid and oriented nucleation on the monolayer/solution interface. The oriented KDP crystals show a good second harmonic generation(SHG) signal.
