Chain Dimensions in Poly(ethylene oxide)/Poly(methyl methacrylate) Blends

Zeroni, Ilan; Lodge, Timothy P.

doi:10.1021/ma702512q

Cited by 8 publications

(6 citation statements)

References 18 publications

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“…Surrounding the Au core is a layer of uniform density molecules with a thickness of approximately 3.5 nm, which is an order of magnitude less than the predicted value of t PEG . The SLD measured is on the order of that expected for PEG (ρ PEG ≈ 5 × 10 –7 Å –2 ), but this value of the SLD is also close to that expected if no SH-PEG were present at all (cf., Figure b). The SH-PEG chains have an average radius of gyration of 3.1 nm and a grafting density σ ≈ 0.002 ± 0.0005 chains/nm 2 .…”

Section: Resultssupporting

confidence: 80%

Probing the Structure, Composition, and Spatial Distribution of Ligands on Gold Nanorods

Hore

Ye²,

Ford³

et al. 2015

Nano Lett.

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The structure and size of ligands attached to the surfaces of gold nanorods, such as adsorbed surfactants or grafted polymers, are important considerations that facilitate the use of such nanoparticles in the human body, in advanced materials for energy harvesting, or in devices for single molecule detection. Here, we report small-angle neutron scattering (SANS) measurements from surfactant or poly(ethylene glycol) (PEG) coated gold nanorods in solution, which quantitatively determine the location, structure, and composition of these surface layers. In addition, by synthesizing gold nanorods using seed crystals which are coated with deuterated cetyltrimethylammonium bromide (dCTAB), we are able to exploit the isotopic sensitivity of SANS to study, for the first time, the retention of surfactant from the seed crystals to the final gold nanorod product, finding that very little exchange of the deuterated with hydrogenated surfactant occurs. Finally, we demonstrate that, when Au NRs are PEGylated using standard techniques, the surfactant bilayer remains intact, and while mass spectrometry detects the presence of both surfactant and PEG, the composition as measured from SANS is predominantly that of the surfactant. These measurements not only provide new insight into the synthesis and functionalization of gold nanorods but provide a quantitative picture of the structure of grafted polymer and surfactant layers on gold nanorod surfaces which has implications for the fabrication of plasmonic and biomedical materials.

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Section: Resultssupporting

confidence: 80%

Probing the Structure, Composition, and Spatial Distribution of Ligands on Gold Nanorods

Hore

Ye²,

Ford³

et al. 2015

Nano Lett.

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“…One of the most exploited ones is its use as polymer electrolyte, 1,2 but it can also be employed for many other very different purposes, such as in the cosmetic and pharmaceutical fields. [3][4][5] Recently, this homopolymer has also drawn attention for its dynamic behavior in miscible blends with polymers of much higher glass transition temperatures T g , such as poly͑methyl methacrylate͒ [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] and poly͑vinyl acetate͒. 21,23,24 This is due to the rather unusual dynamics displayed by PEO in such blends, which could be attributed to confinement effects induced by the rigid high-T g -component.…”

Section: Introductionmentioning

confidence: 99%

Study of the dynamics of poly(ethylene oxide) by combining molecular dynamic simulations and neutron scattering experiments

Brodeck

Álvarez

Arbe

et al. 2009

The Journal of Chemical Physics

128

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We performed quasielastic neutron scattering experiments and atomistic molecular dynamics simulations on a poly(ethylene oxide) (PEO) homopolymer system above the melting point. The excellent agreement found between both sets of data, together with a successful comparison with literature diffraction results, validates the condensed-phase optimized molecular potentials for atomistic simulation studies (COMPASS) force field used to produce our dynamic runs and gives support to their further analysis. This provided direct information on magnitudes which are not accessible from experiments such as the radial probability distribution functions of specific atoms at different times and their moments. The results of our simulations on the H-motions and different experiments indicate that in the high-temperature range investigated the dynamics is Rouse-like for Q-values below approximately 0.6 A(-1). We then addressed the single chain dynamic structure factor with the simulations. A mode analysis, not possible directly experimentally, reveals the limits of applicability of the Rouse model to PEO. We discuss the possible origins for the observed deviations.

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“…Commercially available DR1 and PMMA (product reference 182230), with an average molecular weight of Mw ~ 120,000 and a glass transition temperature Tg of 110 °C, were purchased from Sigma-Aldrich, and were used without purification. The statistical segment length of the PMMA (density: ~1.188 g • cm −3 ) used in our study is not available to us, however the statistical segment length of PMMA of a density of 1.13 g • cm −3 is 6.5 Å [52]. A set of mixture solutions of DR1 and PMMA with different concentrations was prepared.…”

Section: Methodsmentioning

confidence: 99%

Optical Characterization of Ultra-Thin Films of Azo-Dye-Doped Polymers Using Ellipsometry and Surface Plasmon Resonance Spectroscopy

et al. 2021

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The determination of optical constants (i.e., real and imaginary parts of the complex refractive index (nc) and thickness (d)) of ultrathin films is often required in photonics. It may be done by using, for example, surface plasmon resonance (SPR) spectroscopy combined with either profilometry or atomic force microscopy (AFM). SPR yields the optical thickness (i.e., the product of nc and d) of the film, while profilometry and AFM yield its thickness, thereby allowing for the separate determination of nc and d. In this paper, we use SPR and profilometry to determine the complex refractive index of very thin (i.e., 58 nm) films of dye-doped polymers at different dye/polymer concentrations (a feature which constitutes the originality of this work), and we compare the SPR results with those obtained by using spectroscopic ellipsometry measurements performed on the same samples. To determine the optical properties of our film samples by ellipsometry, we used, for the theoretical fits to experimental data, Bruggeman’s effective medium model for the dye/polymer, assumed as a composite material, and the Lorentz model for dye absorption. We found an excellent agreement between the results obtained by SPR and ellipsometry, confirming that SPR is appropriate for measuring the optical properties of very thin coatings at a single light frequency, given that it is simpler in operation and data analysis than spectroscopic ellipsometry.

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Chain Dimensions in Poly(ethylene oxide)/Poly(methyl methacrylate) Blends

Cited by 8 publications

References 18 publications

Probing the Structure, Composition, and Spatial Distribution of Ligands on Gold Nanorods

Probing the Structure, Composition, and Spatial Distribution of Ligands on Gold Nanorods

Study of the dynamics of poly(ethylene oxide) by combining molecular dynamic simulations and neutron scattering experiments

Optical Characterization of Ultra-Thin Films of Azo-Dye-Doped Polymers Using Ellipsometry and Surface Plasmon Resonance Spectroscopy

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