Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Synthesis of water-soluble melanin   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.

26
The categories of this paper are: bayes-an
22
The categories of this paper are: chao-dyn
2
The categories of this paper are: math
32
The categories of this paper are: atom-ph
13
The categories of this paper are: quant-ph
30
The categories of this paper are: q-alg
35
The categories of this paper are: mtrl-th
27
The categories of this paper are: comp-gas
31
The categories of this paper are: ao-sci
6
The categories of this paper are: astro-ph
10
The categories of this paper are: q-bio
19
The categories of this paper are: eess
20
The categories of this paper are: acc-phys
5
The categories of this paper are: gr-qc
1
The categories of this paper are: cs
24
The categories of this paper are: dg-ga