Fabrication of porous thin films of block copolymer at the liquid/liquid interface and construction of composite films doped with noble metal nanoparticles

Abstract

Two approaches have been utilized to fabricate thin composite films of amphiphilic polyisoprene-blockpoly(2-vinylpyridine) (PI-b-P2VP) doped with silver and gold nanoparticles. Honeycomb and foam structures were obtained at the interfaces between a chloroform solution of the polymer and aqueous solutions of either AgNO 3 or HAuCl 4 through the first route. For the second route, porous thin films were obtained at the interfaces between a chloroform solution of the crosslinked polymer by S 2 Cl 2 and pure water, immersed in aqueous solutions of either AgNO 3 or HAuCl 4 to adsorb metal precursors and then treated with KBH 4 aqueous solution to form composite films. The catalytic properties of these films were evaluated by assessing the reduction of 4-nitrophenol by KBH 4 in aqueous solutions. It was found that the metal nanoparticles are unstable enough and fused in the film prepared through the first route while the composite film obtained through the second route exhibited good catalytic performance and was more stable during the catalytic reaction. In addition, the porous polymer film is also expected to adsorb other species to form various functional composites. Fig. 7 XPS spectra of sulfur (a, b and d), silver (c) and gold (e) elements in the pure polymer film (a), composite films containing Ag (b and c) and Au (d and e) after treatment with KBH 4 aqueous solution. 69344 | RSC Adv., 2015, 5, 69339-69347 This journal is

Facile solvothermal preparation of Fe3O4–Ag nanocomposite with excellent catalytic performance

“…27 In recent years, self-assembled Ag composite materials have attracted the increasing attention of a large number of scientic researchers, including those in elds such as highperformance nanolms, 28 biosensors, 29 electroless copper plating 30 and catalytic materials. [31][32][33] Thus, in the present work, Ag nanoparticles were speculated to form a magnetic nanocomposite with Fe 3 O 4 particles, which could be expected not only to show good catalytic performance, but also reduce the loss of Ag nanoparticles and increase reusability.…”

Ultrasensitive Chemiresistive Sensor for NO2 Based on Oxidation of a Thiophene Polymer Bearing Oligoethylene Glycol Side Chains

“…The high resolution of N 1s spectra is shown in Figure a, and two different species, one at 399.8 eV and the other at 406.1 eV, were observed on the oxidized film, while no N 1s signal was observed in the pristine film. Based on prior research on NO 2 adsorption on oxide surfaces, species at 406.1 eV can be attributed to physically absorbed NO 2 , while species at 399.8 eV can be attributed to reduced nitrogen. , High-resolution S 2p spectra of NO 2 -doped and pristine pg 4 2T-TT are shown in Figure b; in the pristine film, the S 2p region exhibits two distinct peaks located at binding energies of 162.3 and 163.5 eV, which are attributed to the S 2p 3/2 and S 2p 1/2 spin–orbit components, respectively, and are separated by a spin–orbit splitting of 1.2 eV. , Upon NO 2 exposure, the S 2p peaks shift to a high binding energy of 0.4 eV, indicating the oxidation of the sulfur atom. Results imply that charge transfer occurs between NO 2 and the p­(g42T-TT) film, and the p­(g42T-TT) film also can physically absorb NO 2 molecules.…”

“…Figure S4 shows the results; the film does not recover after 17 h, suggesting the irreversibility of the chemiresistors. This irreversibility can be attributed to the high binding energy between NO 2 and p­(g42T-TT), which arises from the high HOMO level of p­(g42T-TT). ,, The gas sensing setup is illustrated in Figure a. Standard NO 2 gas was diluted with pure nitrogen gas with the flow rate being regulated by a mass flow controller (MFC).…”

Mercaptoalkyl Groups Anchored on the Layer Surface of New α‐Zirconium Phosphate Phosphonates for the Stabilization of Gold Nanoparticles

“…The pair at 163.3/164.5 eV in both figures are attributed to S 2p 3/2 /S 2p 1/2 of R−S−Au, confirming the combination of gold nanoparticles with sulfur [35] . Moreover, the pair at 168.2/169.3 eV in the XPS spectrum of TE_0.7_B (Figure 16) is related to oxidized sulfur that would be generated during the adsorption process of HAuCl 4 , due to the oxidizing abilities of Au(III) [36] …”

“…[35] Moreover, the pair at 168.2/169.3 eV in the XPS spectrum of TE_ 0.7_B (Figure 16) is related to oxidized sulfur that would be generated during the adsorption process of HAuCl 4 , due to the oxidizing abilities of Au(III). [36] Figure 17 shows the Au 4 f XPS spectrum of TE_0.7_B. It is characterised by two photoemission peaks, corresponding to the core-level Au(0) 4f 7/2 and Au 4f 5/2 excitations, separated by a distance of 3.67 eV, with the Au 4f 7/2 binding energy peak position appearing at 84.1 eV.…”