Surface modification of polyethylene through bromination

Surface bromination of low-density polyethylene (LDPE) was carried out by b rief exposure to gaseous bromine followed by UV irradiation. X-ray photoele ctron spectroscopy suggests two different types of C-Br groups. Atomic forc e microscopy and wetting studies reveal that excessive bromination is accom panied by severe surface roughening. A nucleophilic substitution reaction w as used to introduce surface 4-aminobenzenethiolate functionalities. UV spe ctral analysis indicates a grafting density of 2.9 bromine atoms per 100 An gstrom(2) for the first bromination cycle.