Fig. 3. Receding contact angles measured with a sessile-drop
technique for water drops (8-10 mm base diameter; pH 6) on
the PET (detergent bottle) and PVC (pine oil bottle) treated
with a 2 wt% NaOH solution at 75-80°C as a function of alkaline
treatment time. After 30 min of alkaline treatment the
samples were conditioned in a 5-40 mg/l solution (75-80’(Z)
of diisodecyl phthalate plasticizer for 30 min. Samples were
rinsed and dried before contact angle measurements.