Search results for "Light scattering"

Tuning the surface of nanoparticles: Impact of poly(2-ethyl-2-oxazoline) on protein adsorption in serum and cellular uptake

2016

Item does not contain fulltext Due to the adsorption of biomolecules, the control of the biodistribution of nanoparticles is still one of the major challenges of nanomedicine. Poly(2-ethyl-2-oxazoline) (PEtOx) for surface modification of nanoparticles is applied and both protein adsorption and cellular uptake of PEtOxylated nanoparticles versus nanoparticles coated with poly(ethylene glycol) (PEG) and non-coated positively and negatively charged nanoparticles are compared. Therefore, fluorescent poly(organosiloxane) nanoparticles of 15 nm radius are synthesized, which are used as a scaffold for surface modification in a grafting onto approach. With multi-angle dynamic light scattering, asym…

Static Light Scattering as a tool to control extruded liposomes concentration: A novel physicist-friendly approach

Alteration of the structural properties of inulin gels

2019

Abstract In this work, inulin particle gels, prepared with a type of long chain inulin, were examined in terms of their structural properties and mechanical response, depending on the applied shear rates and temperature during gel preparation. The results are interpreted on the basis of a particle gel model, which takes into account the varying gel structure, depending on the sample preparation parameters. X-ray measurements of the inulin powder, used for the experiments, revealed a mostly amorphous powder. The temperature profiles for the sample preparation, chosen from 25 °C to 60 °C with constant stirring at 600 rpm, yielded viscoelastic particle gels with decreasing hardness. By applica…

Assessment of Shear-Induced Structures by Real Space and Fourier Microscopy

2007

We report preliminary measurements of the shear-induced sliding layer structure in an aqueous suspension of highly charged polystyrene spheres. Particle interaction was controlled by advanced conditioning procedures to result in fluid or body-centred cubic equilibrium structures. Shear was applied in an optical plate-plate shear cell of variable slit width. Fourier microscopy yielded complementary information to real space analysis. The accessible range of scattering vectors was (3.5 ≤ k ≤ 7.2) μm−1 We checked the experimental performance by recording the form factor of a non-interacting suspension and structure factors of less dilute suspensions in dependence on electrolyte concentration c…

Three-dimensional dynamic light scattering

1999

Abstract We describe the employment of a novel light-scattering scheme for the decorrelation of multiple scattering in strongly turbid samples. The three-dimensional scheme, which has been proposed already theoretically, shows certain advantages compared with the two-colour apparatus, which is commercially available. We describe our set-up in detail; features are the use of modern semiconductor laser diodes and contemporary single-mode fibre receivers. We show experimentally that the optimal signal-to-noise ratio (or intercept) β opt = 0.20, which is obtainable with our set-up, can be quantitatively calculated from the measured uncertainties in the alignment. In particular, we give a detail…

Broadband photocurrent enhancement in a-Si:H solar cells with plasmonic back reflectors

2014

The authors acknowledge Francesco Ruffino for the AFM measurements. This work was funded by the EU FP7 Marie Curie Action FP7-PEOPLE-2010-ITN through the PROPHET project (Grant No. 264687), the bilateral CNR/AVCR project "Photoresponse of nanostructures for advanced photovoltaic applications", the MIUR project Energetic (Grant no. PON02_00355_3391233) and by the Portuguese Science Foundation (FCT-MEC) through the Strategic Project PEst-C/CTM/LA0025/2013-14 and the research project PTDC/CTM-ENE/2514/2012. Plasmonic light trapping in thin film silicon solar cells is a promising route to achieve high efficiency with reduced volumes of semiconductor material. In this paper, we study the enhance…

Low-cost high-haze films based on ZnO nanorods for light scattering in thin c-Si solar cells

2015

Light scattering from ZnO nanorods (NR) is investigated, modeled, and applied to a solar cell. ZnO NR (120-1300 nm long, 280-60 nm large), grown by low-cost chemical bath deposition at 90 degrees C, exhibit diffused-to-total transmitted light as high as 70% and 30% in the 400 and 1000 nm wavelength range, respectively. Data and scattering simulation show that ZnO NR length plays a crucial role in light diffusion effect. A transparent ZnO NR film grown on glass and placed on top of a 1 mu m thick c-Si solar cell is shown to enhance the light-current conversion efficiency for wavelengths longer than 600 nm. (C) 2015 AIP Publishing LLC.

Tuning size and thermal hysteresis in bistable spin crossover nanoparticles.

2010

Nanoparticles of iron(II) triazole salts have been prepared from water-organic microemulsions. The mean size of the nanoparticles can be tuned down to 6 nm in diameter, with a narrow size distribution. A sharp spin transition from the low spin (LS) to the high spin (HS) state is observed above room temperature, with a 30-40-K-wide thermal hysteresis. The same preparation can yield second generation nanoparticles containing molecular alloys by mixing triazole with triazole derivatives, or from metallic mixtures of iron(II) and zinc(II). In these nanoparticles of 10-15 nm, the spin transition "moves" towards lower temperatures, reaching a 316 K limit for the cooling down transition and mainta…

Nylon-Supported Plasmonic Assay Based on the Aggregation of Silver Nanoparticles: In Situ Determination of Hydrogen Sulfide-like Compounds in Breath …

2019

A procedure for supporting silver nanoparticles (AgNPs) on nylon is proposed. Besides, the membrane has been developed as a solid-phase colorimetric plasmonic sensor for volatile sulfide compounds (VSCs) like H2S, CH3SH, and (CH3)2S. AgNP behavior in the membrane has been studied by UV-vis diffuse reflectance spectrometry, Raman spectrometry, High-resolution transmission electron microscopy (HR-TEM), and Scanning electron microscopy (SEM). The sensor responded by changing its color from yellow in absence of VSCs to several orange/brown colors in the function of VSC concentration as occurs in solution; an increase in the hydrodynamic diameter, estimated by both asymmetrical flow field-flow f…

1985

Using a self-constructed light scattering apparatus, the pressure dependence of the demixing temperature of solutions of PVC 20 000, PVC 37 000 and PVC 70 000 in THE/water was determined up to 1 000 bar for different compositions of the mixed solvent. (The numbers in the codes of the PVC specimens are their approximate molecular weights.) In contrast to the thetasolvents o-xylene and phenetole, the solubility decreases with increasing pressure for all molecular weights and compositions under investigation typically by about 1 K/100 bar. The evaluation of the experimental findings demonstrates that the volume fraction of the nonsolvent in the mixed solvent, φ, is the variable that governs ph…