Studies of Two-Dimensional Morphology at Surface-Functionalized Polyethylene Films

Abstract

Polyethylene simultaneously functionalized with both pyrene labels and amine quencher groups has been studied to determine the extent to which self-organization and segregation of functional groups occurred during formation of a surface-bifunctionalized polymer. By measuring pyrene fluorescence in the presence of surface-bound amine quencher, pyrene fluorescence after the surface bound quenchers had been protonated, and the total amount of polymer-bound pyrene based on the amount of quenching seen with a large excess of an external quencher, we have been able to show that the mixture of functional groups at the surface is not highly segregated. The suggested integrated morphology was further supported by studies where the ratio of pyrene to internal quencher was varied over approximately 2 orders of magnitude. These studies of a bifunctional surface-modified polymer also showed that the percentage of bound pyrene that was internally quenched varied in a roughly linear way with the molar ratio of pyrene to internal quencher and that mild annealing did not change the observed two-dimensional morphology.