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Motoo Tanaka, Y. Kawabata, and M. Matsumoto
[Kobunshi Ronbunshu, Vol.52, No.10, pp.666-668, 1995]
When drops of aqueous NaCl are deposited on LB films of arachidic acid and w-tricosenoic acid (TA), NaCl crystals with the (111) face attached to the LB films result in 30-50 % of cases as shown in Figure 1. This suggests that the molecules apposed at the film surface reorganize on exposure to the NaCl solution in such a manner that the hydrophilic groups are attached to the film/water interface. The arrangement of hydrophilic groups at the reorganized interface is similar but not the same to that of the corresponding monolayer at the monolayer/water interface. This is further supported by the fact that NaCl crystals growing on the (110) face were found on the stearylamine LB film surface. The polymerization of TA LB films suppressed the crystallization of NaCl on the (111) face.
Fig. 1. Polarizing micrograph of NaCl crystals growing on a 5-layer LB film of arachidic acid.