The effect of a series of parameters on the defects in Langmuir-Blodgett (LB) films and the effect of these parameters on the formation of calcium oxalate monohydrate (COM) crystals were investigated by scanning electronic microscopy (SEM) and fluorescence microscopy. The investigated parameters included the kinds of substrates, temperature, deposition parameters (such as deposition surface pressure, compression rate, dipping speed) and the layers of LB films. The defective domains in LB films could induce the formation of circular patterns of COM crystals. The number of such patterns obtained on the quartz substrates was about 5% of that on the mica substrates. When the temperature decreased from 25 to 18 ℃, noncircular patterns of COM crystals appeared and the diameter of these patterns tended to increase. As the deposition surface pressure increased from 2 to 10 mN/m, the number of circular patterns of crystals on the mica substrates decreased and the number of noncircular patterns increased. As the compression rate increased, the number of defects in the LB films increased. As the number of the layers of LB film increased from one to two, three and five, the number of the induced patterns decreased gradually and the size of the patterns also decreased. It indicated that the number of defects in single-layered LB films was more than that in multilayer LB films, and single-layered LB films were more likely to be affected by the substrates.

Key words: Langmuir-Blodgett film, monolayer, calcium oxalate, biomineralization, calculus