Search results for "Static"

Hydrostatic and structural pressure in compressed paper webs and press felts

1995

Direct formation of Sub-Micron and Nanoparticles of a bioinspired coordination polymer based on Copper with Adenine

2017

We report on the use of different reaction conditions, e.g., temperature, time, and/or concentration of reactants, to gain control over the particle formation of a bioinspired coordination polymer based on copper(II) and adenine, allowing homogeneous particle production from microto submicro-, and up to nano-size. Additionally, studies on this reaction carried out in the presence of different surfactants gives rise to the control of the particle size due to the modulation of the electrostatic interactions. Stability of the water suspensions obtained within the time and pH has been evaluated. We have also studied that there is no significant effect of the size reduction in the magnetic prope…

New amphiphilic poly(butadiene)-graft-poly(ethylene oxide)s

1995

Amphiphilic graft copolymers with a poly(butadiene) backbone and poly(ethylene oxide) side chains were synthesized by grafting isocyanateterminated poly(ethylene oxide) on to partially hydroxylated poly(butadiene). The graft copolymers are water soluble if the fraction of hydrophilic poly(ethylene oxide) exceeds 50 wt%. Solutions of graft copolymers in water and tetrahydrofuran were studied by static light scattering and viscosity measurements. By dynamic light scattering in solution it was shown that the graft copolymers form clusters.

Studies on the solution behaviour of self-assembling polymeric systems

1993

Functional groups were attached to styrene-butadiene copolymers with different polymeric architectures and a low molecular weight compound. These polar stickers form binary, chelate-like contacts or extended juntion zones depending on their chemical nature. The solution properties of these amphiphilic species in toluene were studied by static light scattering.

Structure and thermodynamics in polymer blends. Neutron scattering measurements on blends of poly(methyl methacrylate) and poly(styrene-co-acrylonitr…

1992

Abstract Neutron scattering on polymer blends of deutero-poly(methyl methacrylate) (D-PMMA) and poly(styrene-co-acrylonitrile) with 19 wt% acrylonitrile (PSAN-19) exhibits excess scattering for scattering vectors Q≲0.2 nm−1 if the volume fraction of D-PMMA is less than 0.5 and greater than 0.05. The range of occurrence and the amount of excess scattering depends to a certain degree on the procedure of sample preparation. If the excess scattering is eliminated by linear extrapolation from large to small Q in the Zimm representation, the residual scattering intensity in the small and intermediate Q-range can be interpreted by the mean field approach of de Gennes with a concentration-dependent…

Electrochemical Characterization of Polyelectrolyte/Gold Nanoparticle Multilayers Self-Assembled on Gold Electrodes

2006

Polyelectrolyte/gold nanoparticle multilayers composed of poly(l-lysine) (pLys) and mercaptosuccinic acid (MSA) stabilized gold nanoparticles (Au NPs) were built up using the electrostatic layer-by-layer self-assembly technique upon a gold electrode modified with a first layer of MSA. The assemblies were characterized using UV-vis absorption spectroscopy, cyclic and square-wave voltammetry, electrochemical impedance spectroscopy, and atomic force microscopy. Charge transport through the multilayer was studied experimentally as well as theoretically by using two different redox pairs [Fe(CN)(6)](3-/4-) and [Ru(NH(3))(6)](3+/2+). This paper reports a large sensitivity to the charge of the out…

Temperature- and illumination-induced charge-state change in divacancies of GaTe

2010

Temperature-dependent positron annihilation lifetime spectroscopy measurements have been performed in GaTe samples, with and without illumination. The average lifetime shows a monotonous temperature evolution but the lifetime decomposition shows a rich behavior. It is produced by two types of vacancy defects. The vacancy-type defects characterized by their shorter lifetime change their charge state below 100 K and when illuminating with light of an energy of 0.8 eV.

Using the simplified falling head technique to detect temporal changes in field-saturated hydraulic conductivity at the surface of a sandy loam soil

2007

Abstract Determining temporal changes in field-saturated hydraulic conductivity ( K fs ) is important for understanding and modeling hydrological phenomena at the field scale. Little is known about temporal variability of K fs values measured at permanent sampling points. In this investigation, the simplified falling head (SFH) technique was used for an approximately 2-year period to determine temporal changes in K fs at 11 permanent sampling points established at the surface of a sandy loam soil. Additional K fs measurements were obtained by the single-ring pressure infiltrometer (PI) technique to also compare the SFH and PI techniques. The lowest mean values of K fs , M ( K fs ), were det…

Reversible stress softening of collagen based networks from the jumbo squid mantle (Dosidicus gigas).

2014

Dosidicus gigas is the largest and one of the most abundant jumbo squids in the eastern Pacific Ocean. In this paper we have studied the muscle of the mantle of D. gigas (DGM). Morphological, thermal and rheological properties were assessed by means of atomic force microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, differential scanning calorimetry, thermogravimetry and oscillatory rheometry. This study allowed us to assess the morphological and rheological properties of a collagen based network occurring in nature. The results showed that the DGM network displays a nonlinear effect called reversible stress softening (RSS) that has been previously described for …

Vacuum arc deposition of protective layers on glass and polymer substrates

2001

Abstract Vacuum arc deposition allows one to deposit various coatings on insulating and temperature-sensitive substrates (like polymers). An advantage of the vacuum arc deposition technique is the low substrate temperature during the deposition process. A vacuum arc deposition apparatus for the coating of large-area substrates has been developed. Ti, TiN, TiO 2 and diamond-like single and multilayer coatings have been deposited on plastic and glass substrates. The vacuum arc technology permits formation of multilayer colour filters of high uniformity on substrates with dimensions up to 2000×1400 mm 2 . The microstructure, chemical composition and optical properties of the deposited coatings…