Abstract: It was confirmed that sodium dodecyl sulfate(SDS) in dilute water solution (higher than its critical aggregation concentration, but lower than its critical micelle concentration) can be crystallized under the treatment of an electro static field from TEM, X-ray diffraction and DSCexperiments. With the effect of the electro-static field, the high-order single-crystals can be formed, and its crystal structure was the same as that from the recrystallized sample in methanol as judged from X-ray diffraction spectra. In DSC, the enthalpy, corresponding to the first-order phase transition from order to disorder structure, was equal between these two samples, but the transition temperature was lower as its crystal size was smaller. On the contrary, the sample without the electro static field treatment only has much lower order structure.

Key words: Sodium dodecyl sulfate, Electro-static field, Introducing crystrallization