“…The peak at 398.7 eV can be ascribed to the presence of tertiary amine group nitrogens, which have been reported to have binding energies of around 399.0-399.1 eV. 67,68 On the other hand, the peak at 400.1 eV is consistent with the range of binding energies previously reported for amidetype nitrogens (i.e., 399.8-400.7 eV 69,70 ). Significantly, the ratio of the peak areas (peak 400 eV :peak 387.7 eV ) 1.8:1) is quite close to the theoretical value of 2 expected for a PAMAM-OH dendrimer, whose ideal structure contains 124 amide nitrogens and 64 tertiary amine groups.…”
Section: Pt G4 Pamam-oh Synthesis and Characterizationsupporting
We investigated the formation of self-assembled two-dimensional (2-D) arrays of dendrimer-encapsulated platinum nanoparticles (Pt-DENs) using prokaryotic surface-layer (S-layer) proteins as biomacromolecular templates. The Pt-DENs (mean core diameter 1.8 +/- 0.5 nm) were synthesized by chemical reduction of metal ion species complexed within the interior of fourth-generation, hydroxyl-terminated, starburst poly(amidoamine) dendrimers (G4 PAMAM-OH). Detailed structural and elemental composition analyses performed using high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy, electron energy loss spectroscopy, and X-ray photoelectron spectroscopy indicated that the dendrimer-metal nanocomposite particles were crystalline in nature rather than amorphous and that at least some quantity of the platinum found within the particles is present in the expected zerovalent state. By using the S-layer lattices from the acidothermophilic archaeon Sulfolobus acidocaldarius and the Gram-positive bacterium Deinococcus radiodurans as a biotemplate, hexagonal- and honeycomb-ordered arrays of the Pt-DENs were successfully fabricated under a range of different pH conditions via noncovalent nanoparticle-protein interactions. Fast Fourier transform analyses of transmission electron microscopy images verified that the fabricated Pt-DEN assemblies displayed mean periodicities that corresponded well with the lattice constants of the native protein templates (i.e., 22 and 18 nm for S. acidocaldarius and D. radiodurans S layers, respectively). Our results demonstrate that utilizing pre-synthesized Pt-DENs in conjunction with microbial S-layer proteins displaying highly periodic topochemical properties can be an effective, novel route for creating patterned arrays of Pt nanoparticles with potential technological applications.
“…The peak at 398.7 eV can be ascribed to the presence of tertiary amine group nitrogens, which have been reported to have binding energies of around 399.0-399.1 eV. 67,68 On the other hand, the peak at 400.1 eV is consistent with the range of binding energies previously reported for amidetype nitrogens (i.e., 399.8-400.7 eV 69,70 ). Significantly, the ratio of the peak areas (peak 400 eV :peak 387.7 eV ) 1.8:1) is quite close to the theoretical value of 2 expected for a PAMAM-OH dendrimer, whose ideal structure contains 124 amide nitrogens and 64 tertiary amine groups.…”
Section: Pt G4 Pamam-oh Synthesis and Characterizationsupporting
We investigated the formation of self-assembled two-dimensional (2-D) arrays of dendrimer-encapsulated platinum nanoparticles (Pt-DENs) using prokaryotic surface-layer (S-layer) proteins as biomacromolecular templates. The Pt-DENs (mean core diameter 1.8 +/- 0.5 nm) were synthesized by chemical reduction of metal ion species complexed within the interior of fourth-generation, hydroxyl-terminated, starburst poly(amidoamine) dendrimers (G4 PAMAM-OH). Detailed structural and elemental composition analyses performed using high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy, electron energy loss spectroscopy, and X-ray photoelectron spectroscopy indicated that the dendrimer-metal nanocomposite particles were crystalline in nature rather than amorphous and that at least some quantity of the platinum found within the particles is present in the expected zerovalent state. By using the S-layer lattices from the acidothermophilic archaeon Sulfolobus acidocaldarius and the Gram-positive bacterium Deinococcus radiodurans as a biotemplate, hexagonal- and honeycomb-ordered arrays of the Pt-DENs were successfully fabricated under a range of different pH conditions via noncovalent nanoparticle-protein interactions. Fast Fourier transform analyses of transmission electron microscopy images verified that the fabricated Pt-DEN assemblies displayed mean periodicities that corresponded well with the lattice constants of the native protein templates (i.e., 22 and 18 nm for S. acidocaldarius and D. radiodurans S layers, respectively). Our results demonstrate that utilizing pre-synthesized Pt-DENs in conjunction with microbial S-layer proteins displaying highly periodic topochemical properties can be an effective, novel route for creating patterned arrays of Pt nanoparticles with potential technological applications.
“…An increase of about 1.0 eV on the BE value of N 1s indicates the involvement of the nitrogen in hydrogen-bonding interaction. [5][6][7][10][11][12][13][14][15] Figure 5 shows the S 2p spectra of PATM and the PATM/PVPh blends. For PATM, the S 2p spin-orbit split doublet is located at 163.2 and 164.4 eV, with an intensity ratio of 2 to 1, attributed to S 2p 3/2 and S 2p 1/2 , respectively.…”
Section: Resultsmentioning
confidence: 99%
“…The BE value of the high-BE N 1s peak is 400.6 eV. An increase of about 1.0 eV on the BE value of N 1s indicates the involvement of the nitrogen in hydrogen-bonding interaction. − ,− 4 XPS N 1s core-level spectra of PATM (a) and PATM/PVPh blends containing (b) 20, (c) 40, and (d) 60 wt % PVPh.…”
Section: Resultsmentioning
confidence: 99%
“…[5][6][7][8][9] Our recent studies have been focused on the miscibility and interactions in blends of polymers possessing multiple types of interacting sites. [10][11][12][13][14][15] These polymers such as poly(N-acryloyl-N′-methylpiperazine) (PAMP), poly(N-acryloyl-N′-phenylpiperazine) (PAPP), and poly(N-methyl-4-piperidyl methacrylate) (PMPMA) are capable of interacting with proton-donating polymers through two or three types of interacting sites simultaneously.…”
Section: Introductionmentioning
confidence: 99%
“…The formation of a miscible blend between two dissimilar polymers requires the presence of specific interactions. The existence of specific interactions in miscible polymer blends can be detected by spectroscopic techniques such as Fourier transform infrared spectroscopy (FTIR), , solid-state nuclear magnetic resonance spectroscopy (NMR), , and X-ray photoelectron spectroscopy (XPS). − Our recent studies have been focused on the miscibility and interactions in blends of polymers possessing multiple types of interacting sites. − These polymers such as poly( N -acryloyl- N ‘-methylpiperazine) (PAMP), poly( N -acryloyl- N ‘-phenylpiperazine) (PAPP), and poly( N -methyl-4-piperidyl methacrylate) (PMPMA) are capable of interacting with proton-donating polymers through two or three types of interacting sites simultaneously.…”
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