No Cover Image

Journal article 478 views 114 downloads

Melanin system composition analyzed by XPS depth profiling

J.V. Paulin, James McGettrick Orcid Logo, C.F.O. Graeff, Bernard Mostert Orcid Logo

Surfaces and Interfaces, Volume: 24, Start page: 101053

Swansea University Authors: James McGettrick Orcid Logo, Bernard Mostert Orcid Logo

  • 56371.pdf

    PDF | Accepted Manuscript

    ©2021 All rights reserved. All article content, except where otherwise noted, is licensed under a Creative Commons Attribution Non-Commercial No Derivatives License (CC-BY-NC-ND)

    Download (1.4MB)

Abstract

The melanins are a class of natural pigments ubiquitous throughout the biosphere. These pigments are gaining significant attention as advanced materials due to their biocompatibility, optical and electrical properties. The most common form of melanin, eumelanin, has a well-known problem of insolubil...

Full description

Published in: Surfaces and Interfaces
ISSN: 2468-0230
Published: Elsevier BV 2021
Online Access: Check full text

URI: https://cronfa.swan.ac.uk/Record/cronfa56371
Tags: Add Tag
No Tags, Be the first to tag this record!
Abstract: The melanins are a class of natural pigments ubiquitous throughout the biosphere. These pigments are gaining significant attention as advanced materials due to their biocompatibility, optical and electrical properties. The most common form of melanin, eumelanin, has a well-known problem of insolubility in most common solvents. The insolubility has made standard chemical analysis challenging, leading to researchers opting to use X-Ray photoelectron spectroscopy (XPS). However, standard XPS used on melanins and related materials have been limited to being a surface technique, and hence reported values to date may not reflect the bulk. In this work, we have investigated with XPS depth-profiling method the chemical information of the surface and the bulk of powder and thin-films eumelanin and several melanin derivatives. These latter derivatives are modified melanins designed to overcome the insolubility of the standard systems. Our result indicates that there are only few differences in the chemical composition of the melanin chemical structure between the surface and bulk, for either the powder of film samples. Our results show that a basic surface probe is sufficient to obtain an accurate elemental composition for basic melanin samples. As such, our analysis indicates that XPS characterization is an important characterization of polyindolequinone systems in general such as the melanins and polydopamines.
Keywords: X-Ray Photoelectron Spectroscopy, Depth-profile XPS, Polyindolequinone, Eumelanin, Melanin derivatives, Polydopamine
College: Faculty of Science and Engineering
Start Page: 101053