The aggregation structure of monolayer was determine by the balance of electrostatic repulsion among anionic hydrophilic groups and Van der Waals attraction among hydrophobic groups. The aggregating behavior of 2CnSNa monolayer indicated that when n = 12, an amorphous monolayer was formed in the whole compressing procedure; when n = 14, a crystalline monolayer could be formed at high surface pressure; when n = 16, a crystalline monolayer could be formed even at 0 mN.m-1 surface pressure. The results of TEM observation were in accordance with the results of FT-IR anal. The variation of p-A isotherm with the compression speed was also discussed.

Key words: TRANSMISSION ELECTRON MICROSCOPY, INFRARED SPECTROPHOTOMETRY, MONOMOLECULAR FILMS, ACCUMULATE