Example 20
A polyurea copolymer containing benzophenone photoreactive end group is synthesized as follows. 8 mg of 4-aminobenzophenone (40 umol, Sigma Aldrich, St. Louis, Mo.) is dissolved in 15 ml of isopropanol, to which 185 mg of dipiperidyl propane (0.88 mmole, Sigma Aldrich, St. Louis, Mo.) and 52.8 mg of Jeffamine™ ED600 (0.88 mmol Sigma Aldrich, St. Louis, Mo.) is added. After all the amines dissolve, 0.42 ml of isophorone diisocyanate (2 mmol, Sigma Aldrich, St. Louis, Mo.) is added via syringe and the reaction mixture stirs at room temperature for 2 hours. The benzophenone-terminated polyurea can be used without further purification.