[1] INFM, I-20126 Milan, Italy
[2] Univ Milan, Dipartimento Chim Fis & Elettrochim, I-20133 Milan, Italy
[3] Univ Milan, Dipartimento Fisiol Gen & Chim Biol, I-20134 Milan, Italy
[4] Staz Sperimentale Seta, I-20133 Milan, Italy
[5] Ist Guido Donegani SpA, Polimeri Europa, I-28100 Novara, Italy
[6] Univ Milano Bicocca, Dipartimento Fis G Occhialini, I-20126 Milan, Italy