Nanoscale analysis of the interaction between cyanoacrylate and vacuum metal deposition in the development of latent fingerprints on LDPE

Vacuum metal deposition (VMD) has been previously demonstrated as an effective development technique for latent fingerprints, and in some cases has been shown to enhance prints developed with cyanoacrylate (superglue) fuming. This work utilises scanning electron microscopy (SEM) to investigate the interactions of the two development techniques when applied to latent fingerprints on low density polyethylene (LDPE). Cyanoacrylate (CA) is shown to act principally on the eccrine deposits around sweat pores, where polymerisation results in long polymer fibrils a few hundred nanometres in width. Subsequent VMD processing results in additional areas of development, for example between pores. However, the primary mode of deposition of zinc is by interaction with the polymerised CA, the fibrils of which become decorated with zinc nanoparticles. Areas with limited CA deposition and no significant polymerisation are also enhanced with the VMD process, resulting in increased print development.