Research Article Received: 10 September 2014 Revised: 11 November 2014 Accepted article published: 26 December 2014 Published online in Wiley Online Library: (wileyonlinelibrary.com) DOI 10.1002/pi.4861 Non-toxic luminescent carbon dot/poly (dimethylacrylamide) nanocomposite reagent for latent fingermark detection synthesized via surface initiated reversible addition fragmentation chain transfer polymerization Jessirie Dilag, a,b Hilton Kobus, c Yang Yu, a Christopher T Gibson a and Amanda V Ellis a* Abstract Here, non-toxic luminescent carbon nanoparticles, namely carbon dots (C-dots), were facilely synthesized via a one-pot hydrothermal route. Raman, Fourier transform infrared, fluorescence, carbon NMR and X-ray photoelectron spectroscopies revealed that the C-dots possessed a graphitic-like core with an oxidized surface. The oxidized surface of the C-dots allowed for functionalization of the C-dots with a 2-methyl-2-[(dodecylsulfanylthiocarbonyl)sulfanyl]propanoic acid chain transfer agent. Poly(N,N-dimethylacrylamide) (p(DMA)) was then grafted from the C-dot surface via surface initiated reversible addition fragmentation chain transfer (RAFT) polymerization. The resulting luminescent C-dot/polymer nanocomposite, C-dot/p(DMA), was analyzed using UV-visible and fluorescence spectrometry verifying that the functionalized surface was responsible for the C-dots’ luminescence. This C-dot/p(DMA) nanocomposite was water soluble and was used as a solution for the luminescent detection of latent fingermarks deposited on non-porous aluminium foil substrates. © 2014 Society of Chemical Industry Keywords: nanoparticle; carbon; fingermark detection; RAFT polymerization; forensic science INTRODUCTION Fingermark detection in forensic sciences is an indispensable source of evidence for identification purposes. Current attempts to improve the visualization of latent fingermarks are often driven towards luminescent enhancement or detection to obtain opti- mum contrast between the detected latent fingermark and the surface. With current advances in nanoscience and nanotechnol- ogy there has been a drive towards the synthesis and application of fluorescent quantum dots (QDs) in fingermark reagents. 1 – 7 QDs exhibit extraordinary optical and electrical properties making them a desirable component to integrate into these reagents. However, they are conventionally made of toxic metals, in partic- ular cadmium, the most common being cadmium sulfide (CdS) and cadmium selenium (CdSe) QDs. 1 – 11 This work describes a non-toxic approach in which nano-carbons are used, in par- ticular, luminescent carbon nanoparticles called carbon dots (C-dots). 12 – 35 C-dots differ from other carbon nanomaterials such as fullerenes, graphene or nanodiamonds in the amount of graphitic structure or sp 2 character and the degree of oxidation. 14 Interestingly, the source of C-dot fluorescence emission differs from graphene QDs and nanodiamonds. In the case of nanodiamonds and graphene QDs, radiative processes occur within the graphitic core with  - * electronic transfers whereas with C-dots there is devel- oping evidence that fluorescence emission arises from radiative processes occurring at the surface – as a result of oxidation or sur- face passivation. 12 – 14 Oxidation of the surface leaves the surface of the C-dots decorated with oxygen-containing functional groups such as COOH, C - OH and C = O. In particular, it is suggested that the COOH groups are responsible for C-dot luminescent behaviour under UV illumination. 12 – 14,20 – 22 Surface oxidation of C-dots comes about from the synthesis route selected, whether it is from a top down approach (e.g. laser ablation 18 ) or a bottom ∗ Correspondence to: Amanda V Ellis, Flinders Centre for Nanoscale Science and Technology, Flinders University, Sturt Road, Bedford Park, SA 5042, Australia. E-mail: amanda.ellis@flinders.edu.au a Flinders Centre for Nanoscale Science and Technology, Flinders University, Sturt Road, Bedford Park, SA 5042, Australia b Centre for Forensic Science, University of Technology Sydney, Broadway, Ultimo, NSW 2007, Australia c School of Chemical and Physical Sciences, Flinders University, Sturt Road, Bed- ford Park, SA 5042, Australia Polym Int (2015) www.soci.org © 2014 Society of Chemical Industry