*2.3. Polymer Preparation*

A commercial polyurethane resin, Tecoflex EG-100A (Lubrizol Advanced Materials, Inc., Gastonia, NC, USA), was employed to investigate behavior of additives in controlled polymer solutions. Polymer solutions were prepared (0.1 g polymer in 1 mL chloroform), to which photoactive additives, C60 and EO3–C60, were incorporated. After addition of additives, the solutions were vigorously vortexed to ensure complete mixing. After allowing for air bubbles to escape, polymer solutions were poured out into aluminum pans, loosely covered, and allowed to dry. Films with final additive concentrations of 0.25, 0.5, 1.0, 2.5, and 5.0 wt% were prepared.
