Cationic‐Polymer‐Functionalized Zinc Oxide Quantum Dots: Preparation and Application to Iron(II) Ion Detection

Abstract

This research focuses on the synthesis of ZnO quantum dots with a cationic polymer coating consisting of poly[2-(methacryloyloxy)ethyl]-ammonium chloride-co-poly(poly-ethyleneglycol methyl methacrylate (p(METAC-PEOMEMA)) for Fe 2 + detection. The copolymers of p(METAC-PEOMEMA) at various molar ratios of METAC/PEOMEMA (100/0, 38/62, and 9/91) were synthesized by RAFT polymerization. The p(METAC-PEOMEMA) capped trisodium citrate-ZnO quantum dot (p(METAC-PEOMEMA)-ZnO QDs) were prepared via ionic interaction of trisodium citrate-ZnO QDs and p(METAC-PEOMEMA). The optical properties of the polymer-capped ZnO QDs were studied by UV-Vis and fluororescence spectrophotometry. The p(METAC-PEOMEMA)-ZnO QDs exhibited excellent properties such as high monodispersity in particle sizes, good stability, excellent water dispersibility, and good quantum yield of 27-32%. The p (METAC 9 -PEOMEMA 91 )-ZnO QDs is quenched by Fe 2 + with a good selectivity over other metal ions such as Fe 3 + , Hg 2 + , Co 2 + , Pb 2 + , Cd 2 + , Ni 2 + , Ag + , Cu 2 + , and Na + . A good linear relationship between relative fluorescence intensity and the concentration of Fe 2 + ion was observed over an Fe 2 + concentration range from 0.47 μM to 5.6 μM, with a limit of detection and limit of quantitation at 0.34 μM and 0.51 μM, respectively. Its application for the detection of Fe 2 + ion in drinking water samples was demonstrated.[a] Dr.

Journey of ZnO quantum dots from undoped to rare-earth and transition metal-doped and their applications

“…From the different available detection methods such as colorimetry, 128–130 mass spectrometry, 131–133 atomic absorption spectroscopy, 134–136 electrochemical 137–140 and fluorescence 141–145 methods, the fluorescence methods are the most reliable and effective because of their high sensitivity, high efficiency, and operative simplicity. Praethong Laopa and Tirayut Vilaivan 40 synthesized cationic polymer-coated ZnO QDs for the selective detection of the Fe( ii ) ion. The fluorescence study of p(METAC38-PEOMEMA62)–ZnO, p(METAC100–PEOMEMA0)–ZnO, and p(METAC9-PEOMEMA91)–ZnO QDs was investigated in the presence and absence of 10.71 μM metal ions such as Fe 2+ , Fe 3+ , Hg 2+ , Co 2+ , Pb 2+ , Cd 2+ , Ni 2+ , Ag + , Cu 2+ , and Na + .…”

“…38,39 Thus, ZnO QDs can be used as the uorescence probe for the detection of metal ion impurities in drinking water as the detection limit for several ions is very low. 40 ZnO QDs show strong anti-microbial properties at a specic pH 42 as ZnO can be easily dissolved into Zn 2+ . Protected (QDs with any capping agent) QDs release Zn 2+ ion at a specic location depending upon the capping agent.…”

“…38,39 Thus, ZnO QDs can be used as the fluorescence probe for the detection of metal ion impurities in drinking water as the detection limit for several ions is very low. 40 …”

Exploring Functional Polymers in the Synthesis of Luminescent ZnO Quantum Dots for the Detection of Cr6+, Fe2+, and Cu2+

“…This leads to a decrease in their optical and electronic properties. To overcome this issue, several strategies can be employed, including the use of stabilizing agents, such as β-cyclodextrin [4,7], organosilanes [13,14], and polymers [14][15][16][17]. These agents can be added together during the ZnO QDs synthesis (in situ) [14] or post-modification [15] to preserve the stability and luminescence of ZnO QDs.…”

RAFT Hydroxylated Polymers as Templates and Ligands for the Synthesis of Fluorescent ZnO Quantum Dots

“…Research on zinc oxide quantum dots (ZnO QDs) has received considerable interest due to their photoluminescent (PL) properties and nanoscale size [1]. Being an inexpensive and environmentally friendly material makes it an attractive option for its applications in the biological field for the delivery of anti-tumor drugs [2][3][4], as an antimicrobial agent [5][6][7], or in bioimaging [8], but also in other applications such as anti-counterfeiting technology [9], gas sensors [10,11], the detection of metal ions [12][13][14][15][16][17][18], photocatalysis [17][18][19], and optoelectronics [20][21][22][23][24][25]. A recent review on the synthesis, properties, and applications of ZnO QDs was carried out by Singh et al [1].…”