Photopolymerization in water of diacetylenes chemisorbed onto noble metal nanoparticles: a spectroscopic study

Abstract

Gold and silver nanoparticles of different size, decorated by a diacetylenic monomer having a COOH anchor group, were prepared in aqueous dispersions. Topochemical polymerization of the colloidal suspensions was obtained by UV irradiation and studied by means of spectroscopic techniques (UV-visible absorption, IR and Raman spectroscopies). A variety of polymer phases were found in the case of silver nanohybrids. The main contribution for this investigation was supplied by the Raman spectra, which provide detailed information on the polymer forms and on the preferred conformation of the alkylic side chains.

FT‐Raman spectroscopy—a rapid and reliable quantification protocol for the determination of natural indigo dye in Polygonum tinctorium

“…[3] The main advantage of Raman techniques compared to FT-IR is the weak resonance of water molecules and hence the possibility of in situ analysis of aqueous samples such as mammalian tissue [4] and biomaterials [5 -8] or even aqueous solutions. [9,10] In addition, laser excitation in the near-infrared (NIR) range does not cause the destruction of samples, and in most cases the spectra are free of fluorescence [11] compared to when using laser excitations in the visible region. [12] Hence, FT-Raman has developed as the preferred method for the analysis of the origin and composition of dyes or pigments in precious and ancient arts and crafts.…”

Novel Polydiacetylene-Functionalized Nanostructures for Sensing Applications

“…the more common, less conjugated red phase, with the exciton and its satellite band at around 551 and 504 nm, respectively, (Figs. 3(b) and 3(c)), and the more unusual highlydelocalized bluish-green one, evidenced by the maximum peaked at 690 nm [9,12,13] (Fig. 3(b)).…”

Structural properties of photochromic polyPCDA: A computational study

“…Experimentally, double and triple CC bond stretching frequencies have been reported at 1513, 1484, 1448 cm À1 and at 2115, 2080, 2073 cm À1 , respectively, for the red, blue and bluish-green forms [12].…”

“…The lowest absorption band centered around 650 nm in the blue form shifts to 540 nm in the red [9][10][11]. Recently, a study on the photopolymerization of 10,12-pentacosadiynoic acid, CH 3 A(CH 2 ) 11 AC"CA C"CA(CH 2 ) 8 ACOOH (PCDA), adsorbed on Ag nanoparticles has reported on a third chromatic form of the polymer [12,13]. At the first stage of UV exposure the blue form is obtained, as indicated by the absorption maximum around 645 nm, which evolves at longer irradiation times into a bluish-green form absorbing at 675 nm and coexisting with the red, k abs,max $ 550 nm.…”