The role of wetting effects on the development of latent fingermarks

Fingermarks are believed to be unique to each individual and hence play a pivotal role as a form of evidence. However, despite significant ongoing research into fingermark recovery techniques, there are still many areas that need to be explored. Due to the immense potential of fingermarks as an effe...

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Main Author: Thandauthapani, Tshaiya Devi
Format: Thesis (University of Nottingham only)
Language:English
Published: 2019
Subjects:
Online Access:https://eprints.nottingham.ac.uk/56453/
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author Thandauthapani, Tshaiya Devi
author_facet Thandauthapani, Tshaiya Devi
author_sort Thandauthapani, Tshaiya Devi
building Nottingham Research Data Repository
collection Online Access
description Fingermarks are believed to be unique to each individual and hence play a pivotal role as a form of evidence. However, despite significant ongoing research into fingermark recovery techniques, there are still many areas that need to be explored. Due to the immense potential of fingermarks as an effective method of identifications an attempt has been made in the present work to analyse one particular area that has been overlooked - the impact of wetting properties of different surfaces. The aim of the study is to investigate the physical and chemical changes in fingermark constituents deposited on polymer substrates of different water contact angles when recovered using the cyanoacrylate fuming technique with the use of camera and FTIR spectroscopy. The effect of aging and the environmental conditions on latent fingermarks was also studied. Meanwhile, visualisation of latent fingermark on metal substrates developed using the conventional technique (cyanoacrylate fuming and staining) was compared with the chemical images obtained from ToF-SIMS. Images from optical microscope showed the influence of substrate wetting properties in the distribution of both types of sweat material (sebaceous and eccrine) which in turn affected the cyanoacrylate polymerisation. On hydrophilic substrates, the fingermark was deposited as a continuous film that allowed higher cyanoacrylate polymerisation whereas on hydrophobic surfaces an irregularly shaped fingermark deposit led to lower amount of cyanoacrylate polymerisation. Aging of fingermarks was shown to be influenced by the underlying substrate wetting properties as fingermark constituents decreased more rapidly on hydrophobic surfaces. The eccrine fingermark aged significantly faster than sebaceous fingermark due to the more volatile nature of the fingermark constituents. Experimental evidence showed that both types of marks developed well by producing a clear fingermark pattern with cyanoacrylate fuming after aged for a week when the marks were not exposed to environmental conditions in comparison to the marks that were aged for the same period of time but exposed to airflow and light. The chemical images from ToF-SIMS demonstrated an exceptional quality of fingermarks (clear ridge definitions and sweat pore position) on the metal surfaces for periods of up to 26 days after deposition when the samples were stored at ambient conditions whereas conventional techniques showed little to no evidence of fingermarks being present on the metal surfaces after a few days.
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spelling nottingham-564532025-02-28T14:28:25Z https://eprints.nottingham.ac.uk/56453/ The role of wetting effects on the development of latent fingermarks Thandauthapani, Tshaiya Devi Fingermarks are believed to be unique to each individual and hence play a pivotal role as a form of evidence. However, despite significant ongoing research into fingermark recovery techniques, there are still many areas that need to be explored. Due to the immense potential of fingermarks as an effective method of identifications an attempt has been made in the present work to analyse one particular area that has been overlooked - the impact of wetting properties of different surfaces. The aim of the study is to investigate the physical and chemical changes in fingermark constituents deposited on polymer substrates of different water contact angles when recovered using the cyanoacrylate fuming technique with the use of camera and FTIR spectroscopy. The effect of aging and the environmental conditions on latent fingermarks was also studied. Meanwhile, visualisation of latent fingermark on metal substrates developed using the conventional technique (cyanoacrylate fuming and staining) was compared with the chemical images obtained from ToF-SIMS. Images from optical microscope showed the influence of substrate wetting properties in the distribution of both types of sweat material (sebaceous and eccrine) which in turn affected the cyanoacrylate polymerisation. On hydrophilic substrates, the fingermark was deposited as a continuous film that allowed higher cyanoacrylate polymerisation whereas on hydrophobic surfaces an irregularly shaped fingermark deposit led to lower amount of cyanoacrylate polymerisation. Aging of fingermarks was shown to be influenced by the underlying substrate wetting properties as fingermark constituents decreased more rapidly on hydrophobic surfaces. The eccrine fingermark aged significantly faster than sebaceous fingermark due to the more volatile nature of the fingermark constituents. Experimental evidence showed that both types of marks developed well by producing a clear fingermark pattern with cyanoacrylate fuming after aged for a week when the marks were not exposed to environmental conditions in comparison to the marks that were aged for the same period of time but exposed to airflow and light. The chemical images from ToF-SIMS demonstrated an exceptional quality of fingermarks (clear ridge definitions and sweat pore position) on the metal surfaces for periods of up to 26 days after deposition when the samples were stored at ambient conditions whereas conventional techniques showed little to no evidence of fingermarks being present on the metal surfaces after a few days. 2019-07-17 Thesis (University of Nottingham only) NonPeerReviewed application/pdf en arr https://eprints.nottingham.ac.uk/56453/1/PhD%20Thesis_Tshaiya%20Devi.pdf Thandauthapani, Tshaiya Devi (2019) The role of wetting effects on the development of latent fingermarks. PhD thesis, University of Nottingham. fingermarks fingerprints identification polymers
spellingShingle fingermarks
fingerprints
identification
polymers
Thandauthapani, Tshaiya Devi
The role of wetting effects on the development of latent fingermarks
title The role of wetting effects on the development of latent fingermarks
title_full The role of wetting effects on the development of latent fingermarks
title_fullStr The role of wetting effects on the development of latent fingermarks
title_full_unstemmed The role of wetting effects on the development of latent fingermarks
title_short The role of wetting effects on the development of latent fingermarks
title_sort role of wetting effects on the development of latent fingermarks
topic fingermarks
fingerprints
identification
polymers
url https://eprints.nottingham.ac.uk/56453/