Synthesis of Metallic and Metal Oxides Nanoparticles by using Poly(4- vinylpyridine) (P4VP), Poly(2-vinylpyridine) (P2VP) Homopolymers and Polyphosphazene-b-P2VP Block Copolymers as Solid Templates

Abstract Starting from poly(4-vinylpyridine) [(P4VP)n; Mw = 6000 (1a); 160000 (1b)]; poly(2-vinylpyridine) Mw = 37500 (1c) and [N=P(O2CH2CF3)]m-b-P2VP20 block copolymers [m = 20 (2a); 60 (2b) and 100 (2c)], series of metal- containing homopolymers {[P4VP(PtCl2)x]6000 (1a-Pt), [P4VP(PtCl2)x]160000 (1b-Pt), [P2VP(PtCl2)x]37500 (1c-Pt), [P4VP(ZnCl2)x]6000 (1a-Zn), [P4VP(ZnCl2)n]160000 (1b-Zn), [P2VP(ZnCl2)n]37500 (1c-Zn), [P4VP(Eu(NO3)3]6000 (1a-Eu), and [P4VP(Eu(NO3)3]160000 (1b-Eu) P2VP[(Eu(NO3)3]37500 (1c-Eu) and block copolymers {[N=P(O2CH2CF3)]20-b-[P2VP(Eu(NO3)3)x]20 (2a-Eu), [N=P(O2CH2CF3)]60-b-[P2VP(Eu(NO3)3)x]20 (2b-Eu) and [N=P(O2CH2CF3)]100-b-[P2VP(Eu(NO3)3)x]20 (2c-Eu)} have been successfully prepared by using a direct a straight forward solution metodólogy. Solid-state pyrolysis of the as prepared metal containing polymeric precursors lead to the formation of a variety of different metallic and metal oxide nanoparticles (Pt, ZnO, Eu2O3 and EuPO4) depending on the composition and nature of the polymeric template precursor. Thus, whereas Eu2O3 nanostructures were obtained from europium-containing homopolymers (1a-Eu, 1b-Eu and 1c-Eu), EuPO4 nanostructures were achieved when phosphorus-containing block copolymer precursors (2a-Eu, 2b-Eu and 2c-Eu) were employed. Importantly, and although both Eu2O3 and EuPO4 nanostructures exhibit a strong luminescence emission, this is strongly influenced by the nature and composition of the macromolecular metal-containing polymer template. Thus, when P2VP europium-containing homopolymers (1a-Eu, 1b-Eu and 1c-Eu) were employed, the highest emission intensity corresponds to the lowest molecular weight homopolymer template (1a-Eu), whereas opposite behavior was observed when block copolymer precursors (2a-Eu, 2b-Eu and 2c-Eu) were used (highest emission intensity corresponds to 2c-Eu). The intensity ratio of the emission transitions 5D0→ 7F2/5D0→ 7F1 suggest a different symmetry around the Eu3+ ions depending on the nature of the polymeric precursor, which also influences the sizes of the as prepared Pt, ZnO, Eu2O3 and EuPO4 nanostructures.