A series of perylene diimide (PDI) derivatives based on pentaphenylbenzene backbone (n-PDI

n = 2

3

4) were synthesized by 2-(2-methoxyethoxy)-ethanol

triethylene glycol monomethyl ether

methyl tetraglycol

3

4

9

10-perylenetetracarboxylic dianhydride as starting materials. By varying the staring materials

n-PDI (n = 2

3

4) with 2

3

and 4 swallow-tail substituents were obtained. The structures of n-PDI (n = 2

3

4) were characterized by IR

1H NRM. Thermogravimetric analysis (TGA) and derivative thermogravimetry (DTG) show that the decomposition temperatures of n-PDI (n = 2

3

4) are all above 200℃

indicative of well thermal stability of n-PDI (n = 2

3

4) in corrosion additive field. The surface active parameters and the thermodynamic parameters of n-PDI were investigated. A series of surface active parameters were obtained from surface tension measurement. It indicated that n-PDI (n = 2

3

4) with the shorter ethoxy chain showed the higher surface activity. The thermodynamic parameters of micellization process and the gas-liquid interface adsorption process were derived from critical micelle concentration (CMC) at different temperatures. It indicated that micellization process and the gas-liquid interface adsorption process were spontaneous. Gibbs free energy of the micellization was determined mainly by entropy at low temperature. At higher temperature

however it was mainly dominated by enthalpy. SEM image showed that gemini surfactants on the zinc electrodes have corrosion inhibition.