  Melanins are promising materials for organic bioelectronics devices like
transistors, sensors and batteries. However, in general, melanin either natural
or synthetic has low solubility in most solvents. In this study, the chemical
structural changes of melanin synthesized, by the auto oxidation of L-DOPA, are
analyzed for a new synthetic procedure using a reactor with oxygen pressure of
4 atm. UV-Vis spectroscopy, FTIR, C-NMR, XPS and TEM are use to characterize
the material. Under oxygen pressure, the synthesis of melanin is accelerated
and the polymer obtained is found to have higher carbonyl groups compared to
conventional synthetic melanin. As a consequence it has higher homogeneity and
is soluble in water. To explain these findings a reaction mechanism is proposed
based on current melanogenesis models.
