Abstract: Using a Langmuir-Blodgett film of dipalmitoylphosphatidylcholine(DPPC), a model of biomembranes, as a template, we succeed in obtaining oriented KH₂PO₄(KDP) crystals toward crystal face (100) under well-compressed DPPCmonolayer. This is explicable in terms of the geometrical complementarity between KDPand the DPPCmonolayer. It is found that the distances between the closest K-K (0.416 nm) fit the d(100) network spacing of DPPCmonolayer(0.420 nm), which results in that the special activation energy for nucleation exists in the interface covered with DPPCmonolayer. DPPCmonolayer has a very strong selected catalysis on the crystallization of KDPcrystal face (100), and drives KDPrapid and oriented nucleation on the monolayer/solution interface. The oriented KDPcrystals show a good second harmonic generation(SHG) signal.

Key words: Dipalmitoylphosphatidylcholine, KDP, Oriented growth, Second harmonic generation