Fluorescent amphiphilic silica nanopowder for developing latent fingerprints

Developing latent fingerprints with silica nanopowder is strategically beneficial due to its synthetic simplicity, low production cost, high surface area and easy tailoring of surface phenomena. However, it is necessary to optimize the surface amphiphilicity of silica nanoparticles for their use in a powder dusting method. In this work, we demonstrate the tuning of amphiphilicity of silica nanopowders (average size 135 +/- 10 nm) by modifying hydrophilic silica surfaces with different alkyl chains (e.g. -C5H11, -C11H23 and -C17H35). This structural amendment maximizes the efficacy of silica nanopowder for developing latent fingerprints. It was also observed that -C11H23 and -C17H35 containing amphiphilic silica nanopowders perform very efficiently for latent fingerprint development under visible light. To produce a luminescent silica nanopowder with a similar surface character, a Pt(II)C<^>N<^>N-C12H25 luminophore with long hydrophobic aliphatic chain (-C12H25) was introduced to the silica surface. This fluorescent and amphiphilic silica nanopowder performs very efficiently for developing latent fingerprints on various surfaces under illumination with 365 nm wavelength UV light.