Formation of silver clusters by borohydride reduction of AgNO3 in polyacrylate aqueous solutions

Abstract

Chemical synthesis of the compounds of silver clusters and polyacrylate was performed using sodium borohydride as a metal cation reducing agent. The effect of silver cation content on spectral properties and structure of the synthesized metal-polymer systems was studied by optical spectroscopy and transmission electron microscopy.

Borohydride reduction of Ag+ in aqueous poly(acrylic acid-co-acrylamide) solutions

“…However, at [NaBH 4 ] > 1.05 × 10 -5 M, a broad absorption band with a maximum at At [NaBH 4 ] 1.76 × 10 -5 -2.81 × 10 -5 M, the absorption band in the range of 280-350 nm is broad ened toward longer wavelengths, the intensity of absorption in the visible region further increases with more pronounced separation into two bands with maxima at 450-500 and ≈600 nm (LAB). The maxi mum of the LAB, which is related to the formation of weakly charged linear silver clusters (m ≥ 8, n ≤ 4) [2][3][4], is shifted toward the infrared region due to the linear ordering of clusters on the copolymer chain, with the leading increase being observed for the inten sity of this band (Fig. 2).…”

“…It was assumed that the formation of blue silver requires the presence of excess carboxyl groups and their rather dense arrange ment in polyanion chains [3]. It was hypothesized [4] that the position of the long wave absorption band (LAB), which imparts the characteristic blue color to the solutions, and its shift in the reaction mixture spectrum in a region of 600-800 nm are due to linear ordering of silver clusters coordinated by oxygen atoms of two neighboring carboxyl groups.…”

Morphology of Silver Nanoparticles in the Micelle-Forming Block Copolymers

“…The process of nanoparticle formation was controlled by the changes in the position (λ max ) and the integral intensity (S) of the surface plasmon resonance band (SPRB), which was displayed in a visible region of spectrum [14]. More detail this experiment has been presented in previous works [21,22].…”

“…The reduction of silver ions was carried out in aqueous polymer solutions with the eightfold molar excess of NаВН 4 that allowed achieving practically complete conversion of Ag + ions to zero-valent state in a selected region of AgNO 3 concentrations (С AgNO3 = 1.82·10 −2 kg·m −3 ) [14,15]. We used concentration of the polymeric matrices С m = 2.0 kg·m −3 .…”

“…Polymeric solutions was mixed with AgNO 3 and kept for 30 min in a dark box; then the reducing agent was added. At the same time, borohydride anions participate also in some side reactions, due to which their essential excess is used to enhance the yield of Ag nanoparticles [14]. Also the reduce Ag nanoparticles without polymer matrix (test system) was investigated.…”