The Interphase Electric Properties of SDS/n‐C₅H₁₁OH/L‐Phenylalanine/H₂O System

Abstract

The interphase electric properties of the SDS/n‐C₅H₁₁OH/L‐phenylalanine (L‐phe)/H₂O system have been investigated by the method of AC impedance. The results show that at the constant weight ratio of n‐C₅H₁₁OH/H₂O=50/50 and the total L‐phe concentration, with an increase of the total concentration of sodium dodecyl sulfate (SDS) in the system, the structure of the upper phase always takes W/O (water/oil) form, whereas that of the lower phase changes from O/W (oil/water) to BI (bi‐continuous) when the total concentration of SDS reaches 3.0%. The microstructure transition of microemulsions at the SDS concentration of 3.0% makes the increase of the interphase capacitance and interphase charge‐transfer current apparently slow down with further increase of SDS concentration. In addition, L‐phe can transfer from the lower phase to the upper phase with increase of the total SDS concentration. At a constant concentration of SDS, with an increase of the total L‐phe concentration, the concentrations of L‐phe in both the upper and lower phases increase the interphase capacitance and the interphase charge‐transfer current of the system increase first rapidly and then slowly, but the interphase resistivity of the system decreases first rapidly and then slowly.

Keywords:

• SDS
• microemulsion
• L‐phenylalanine
• capacitance
• resistivity
• charge‐transfer current

Acknowledgment

This work was supported by the National Nature Science Foundation of China (20233010).