Surface characterizations of poly(ethylene terephthalate) film modified by a carbohydrate-bearing photoreactive azide group

Grafting of a carbohydrate UV-reactive molecule, the β-d-galactopyranosyl-(1–4)-1-N-[2-(4-azidophenyl amino)-ethylamino]-1-deoxy-d-glucitol (AzPhLac), has been achieved on poly(ethylene terephthalate) film. The dependence of surface density and yield of grafted AzPhLac have been studied versus the number of moles of UV-treated AzPhLac via the deposit of a drop of solution with a known volume and concentration. A nearly complete grafting of initial AzPhLac molecules was reached for the lowest concentration and lowest volume of solution deposit conditions. Grafting density values in the range of 29–181 nmol/cm2 confirm the polymeric nature of the grafted layer. FTIR–ATR demonstrated the heterogeneity in thickness of the grafted surface due to the drop-deposit method and solvent evaporation process. AFM (imaging) allowed us to find a correlation between grafting density and rms roughness. Water-contact angle and AFM (contact mode) gave further evidence of the hydrophilic nature of the extreme surface.