Surface modification of polyethylene films via bromination: Reactions of brominated polyethylene with aromatic thiolate compounds

Polyethylene-bromine (PE-Br) was modified by nucleophilic substitution reactions with aromatic thiolate compounds. The amount of replacement was examined in terms of S/C mole ratio using X-ray photoelectron spectroscopy. The stronger the electron donating in the substituent group on thiolate anion, the higher the amount of substitution reaction at the PE-Br surface. The S/C ratio is the largest for PE-S-Ph-NH₂ due to the enhancing nucleophilicity of thiolate anion by the amino group. The ratio in PE-S-Ph-COOH is the smallest because of the electron-withdrawing character of the COOH group. However, the film revealed an improvement in wettability, due to high hydrophilicity.