Synthesis of mesoporous SiO ₂ coating containing chlorine phenol–formaldehyde resin (Cl–PFR) composites for effective fingerprint detection

As a type of nonmetals fluorescent reagent, the described chlorine phenol–formaldehyde resin (Cl–PFR) nanoparticles (NPs) were synthesized using a facile method. The as-synthesized Cl–PFR NPs can emit strong green fluorescence emission under 365 nm ultraviolet (UV) light irradiation. As mesoporous silica (MSN) NPs have a large specific area, strong adsorption, and uniform dispersion, MSN-coated Cl–PFR composites were prepared by mixing Cl–PFR and MSN NPs together. The as-synthesized multifunctional composites combining the advantages of the green fluorescence of Cl–PFR, and the strong adhesion of MSN was applied to detect potential fingerprints. Different base fingerprints (glass, paper, aluminium sheets, rough stones, tape) could be clearly observed in the presence of the Cl–PFR@MSN–NH2 composites. Furthermore, fingerprints that had been aged for 3 months and washed with water several times could also be clearly displayed using the multifunctional composites. This study provided a simple, economical, and nontoxic fluorescent reagent for application in fingerprint detection.