An integrated method for developing and transferring latent fingerprints based on interfacial separation of polydopamine films

Abstract

The invention discloses an integrated method for implementing latent fingerprint development and transfer based on polydopamine film interface separation. The method comprises the following steps: (1) coating one side of a PDMS (Polydimethylsiloxane) film with a PDA (Polydopamine) film to form a composite film; (2) performing aging pretreatment on a carrier carrying latent fingerprints, then lightly attaching the carrier to the composite film in a mode that the PDA film is used as a contact face, standing for 5s-20min, and then separating the PDMS film from the PDA film, wherein the PDA film and latent fingerprint contact part is left on the PDMS film marked as a transfer film, and the other part is left on the carrier; and (3) separately performing electroless deposition of silver on the transfer film and the carrier to obtain a latent fingerprint image with matched male and female sides. By adopting the method, the latent fingerprints can be developed on different surfaces, and can also be transferred to the PDMS surface for sampling and storage, so that the method has huge application potential in scene fingerprint extraction and the like.

Description

technical field [0001] The invention belongs to the technical field of latent fingerprint development, and in particular relates to an integrated method for realizing latent fingerprint development and transfer based on polydopamine film interface separation. Background technique [0002] Fingerprints are the concave-convex lines or the imprints left by the folds of the skin on the fingertips at the end of the fingers. They are distributed in a "wave" shape (ridges) and ups (valleys). They are different from person to person and remain unchanged throughout life. It was once called "the head of evidence" by the judiciary. Fingerprints can be divided into three categories: obvious fingerprints (transfers from hands stained with paint, blood, ink, etc.), molded fingerprints (formed by fingers touching and imprinting on soft substances such as candles and clay), and invisible fingerprints. Latent fingerprints (transferred from finger secretions and invisible pollutants carried ...

AI Technical Summary

Problems solved by technology

Optical visualization methods generally require complex instrument assistance and are not suitable for on-site analysis. For example, luminescence methods require chemiluminescence instruments, infrared spectroscopy and mass spectrometry require spectrometers, reflection methods require laser lamps, etc. Higher requirements, such as powder method is difficult to show on wet surface, water immersion object and rough surface, vacuum metal deposition method is difficult to show on porous surface, etc.; chemical display method, such as ninhydrin method and DFO method, due to ninhydrin and DFO The reaction is slow at room temperature, and it will react with the chemical components in the fingerprint, resulting in a long development time and affecting the further analysis of the fingerprint; so the physical and chemical visualization method is a method used more in the field of fingerprint development

[0004] As for the physical and chemical visualization method, the application of the visualization agent is the key to determine the quality of fingerprint visualization, but the physical and chemical visualization of the prior art still has the disadvantages of poor development quality and high requirements on the carrier surface, which is not conducive to on-site fingerprint extraction and sampling preservation. And it cannot realize the synchronization of fingerprint development and storage

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