scholarly journals Monolith formation and ring-stain suppression in low-pressure evaporation of poly(ethylene oxide) droplets

2012 ◽  
Vol 695 ◽  
pp. 321-329 ◽  
Author(s):  
Kyle A. Baldwin ◽  
Samuel Roest ◽  
David J. Fairhurst ◽  
Khellil Sefiane ◽  
Martin E. R. Shanahan
Keyword(s):  
Ethylene Oxide ◽  
Triple Line ◽  
Deposition Process ◽  
Low Pressure ◽  
Quantitative Model ◽  
Dimensionless Number ◽  
Coffee Ring ◽  
Wide Range ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene

AbstractWhen droplets of dilute suspensions are left to evaporate the final dry residue is typically the familiar coffee-ring stain, with nearly all material deposited at the initial triple line (Deegan et al., Nature, vol. 389, 1997, pp. 827–829). However, aqueous poly(ethylene oxide) (PEO) droplets only form coffee-ring stains for a very narrow range of the experimental parameters molecular weight, concentration and drying rate. Instead, over a wide range of values they form either a flat disk or a very distinctive tall central monolith via a four-stage deposition process which includes a remarkable bootstrap-building step. To predict which deposit will form, we present a quantitative model comparing the effects of advective build-up at the triple line to diffusive flux and use this to calculate a dimensionless number $\chi $. By experimentally varying concentration and flux (using a low-pressure drying chamber), the prediction is tested over nearly two orders of magnitude in both variables and shown to be in good agreement with the boundary between disks and monoliths at $\chi \approx 1. 6$.

scholarly journals Complex Extraction of Metals in an Aqueous Two-Phase System Based on Poly(Ethylene Oxide) 1500 and Sodium Nitrate

Molecules ◽  
2019 ◽  
Vol 24 (22) ◽  
pp. 4078 ◽  
Author(s):  
Yulia A. Zakhodyaeva ◽  
Inna V. Zinov’eva ◽  
Elena S. Tokar ◽  
Andrey A. Voshkin
Keyword(s):  
Ethylene Oxide ◽  
Phase System ◽  
Two Phase ◽  
Kinetic Dependence ◽  
Aqueous Two Phase System ◽  
Wide Range ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene ◽  
Complex Extraction ◽  
Extraction Of Metals

This article presents an ecologically safe aqueous two-phase system based on poly(ethylene oxide) with a molecular weight of 1500, designed for complex extraction of Ni(II), Co(II), Fe(III), Mn(II), Zn(II), Cu(II), and Al(III) from nitrate solutions. A kinetic dependence has been investigated for a distribution ratio for the metals examined. The influence of pH-values, temperature, initial metal concentration, and nitric acid content have on the extraction of a wide range of metals in the heterogeneous poly(ethylene oxide) 1500-NaNO3-H2O system has been discovered. As a result, the complex extraction of metals (EMe > 60%) was achieved in one step of extraction without introducing additional chemicals into the system.

scholarly journals Understanding the surface properties and rheology of a silica suspension mediated by a comb-type poly(acrylic acid)/poly(ethylene oxide) (PAA/PEO) copolymer: effect of salinity

Soft Matter ◽  
2018 ◽  
Vol 14 (23) ◽  
pp. 4810-4819 ◽  
Author(s):  
Dingzheng Yang ◽  
Bin Yan ◽  
Li Xiang ◽  
Haolan Xu ◽  
Xiaogang Wang ◽  
...  
Keyword(s):  
Acrylic Acid ◽  
Ethylene Oxide ◽  
Surface Properties ◽  
High Salinity ◽  
Colloidal Suspensions ◽  
Industrial Applications ◽  
Wide Range ◽  
Silica Suspension ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene

Understanding the surface properties and rheology of colloidal suspensions in the presence of polymer additives with high salinity is of great importance in a wide range of industrial applications.

Transport of nanoparticulate material in self-assembled block copolymer micelle solutions and crystals

2016 ◽  
Vol 186 ◽  
pp. 435-454 ◽  
Author(s):  
Vicki A. Cheng ◽  
Lynn M. Walker
Keyword(s):  
Ethylene Oxide ◽  
Water Soluble ◽  
Polymer Micelle ◽  
Nanoparticle Transport ◽  
Micellar Phase ◽  
Nanoscale Structures ◽  
Wide Range ◽  
Poly Ethylene Oxide ◽  
Self Assembled ◽  
Poly Ethylene

Water soluble poly(ethylene oxide)–poly(propylene oxide)–poly(ethylene oxide) [PEO–PPO–PEO] triblock copolymers self-assemble into thermoreversible micellar crystals comprised of periodically spaced micelles. The micelles have PPO cores surrounded by hydrated PEO coronas and the dimensions of the unit cell of the organized micelles is on the order of several to tens of nanometers. Fluorescence recovery after photobleaching (FRAP) is used to quantify nanoparticle transport in these nanostructured polymer micelle systems. Diffusivity of bovine serum albumin (BSA, Dh ∼ 7 nm) is quantified across a wide range of polymer, or micelle, concentrations covering both the disordered fluid as well as the structured micellar crystal to understand the effects of nanoscale structure on particle transport. Measured particle diffusivity in these micellar systems is reduced by as much as four orders of magnitude when compared to diffusivity in free solution. Diffusivity in the disordered micellar fluid is best understood in terms of diffusion through a polymeric solution, while transport in the structured micellar phase is possibly due to hopping between interstitial sites. These results not only show that the nanoscale structures of the micelles have a measureable impact on particle diffusivity, but also demonstrate the ability to tune nanoscale transport in self-assembled materials.

From coffee ring to spherulites ring of poly(ethylene oxide) film from drying droplet

2018 ◽  
Vol 434 ◽  
pp. 626-632 ◽  
Author(s):  
Yinchun Hu ◽  
Xuerong Zhang ◽  
Maibo Qiu ◽  
Yan Wei ◽  
Qiong Zhou ◽  
...  
Keyword(s):  
Ethylene Oxide ◽  
Oxide Film ◽  
Coffee Ring ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene

scholarly journals IDENTIFICATION OF RHEOLOGICAL PROPERTIES OF POLY(ETHYLENE OXIDE) – WATER SOLUTIONS

2020 ◽  
Vol 63 (9) ◽  
pp. 82-87
Author(s):  
Ryszard Wójtowicz ◽  
Katarzyna Kocewiak ◽  
Andrey A. Lipin
Keyword(s):  
Ethylene Oxide ◽  
Rheological Properties ◽  
Flow Behavior ◽  
Newtonian Fluids ◽  
Shear Stresses ◽  
Water Solutions ◽  
Marquardt Algorithm ◽  
Wide Range ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene

In the paper results of investigations of rheological properties for selected PEO-water solutions are presented. On the basis of measurements, carried out with use of rotational viscosimeter values of shear stresses were determined in the relatively wide range of shear rates. Rheological curves were described by the Ostwald de Waele model (or so-called power-law). The model coefficients such as the fluid consistency coefficient k and the flow behavior index n were determined using Levenberg−Marquardt algorithm for nonlinear estimation. The influence of temperature on properties and behavior examined non-Newtonian fluids was also determined. Results were processed in the curve shift parameter at. Experiments shown a significant effect of poly(ethylene oxide) concentration cPEO on rheological properties of examined solutions. For the lowest concentration (cPEO=1.2%) solutions exhibited properties similar to Newtonian fluids with values of n close to 1. With increasing of PEO concentration in water (cPEO=2.4-4.8%), solutions exhibited properties as non - Newtonian fluids, pseudoplastic, without yield limit. In these cases values of n were below unity and for the highest concentration (cPEO=4.8%) belonged to the range of n=0.5694-0.7536, depending on the temperature. Results of investigations can be used during numerical simulations, design and optimization of industrial equipment, working with fluids of this kind, including mixing vessels, columns or heat exchangers.

The Structure of Radiation Cross-Linked Poly (ethylene oxide) Gels

1971 ◽  
Vol 29 ◽  
pp. 76-77
Author(s):  
C. E. Cluthe ◽  
G. G. Cocks
Keyword(s):  
Molecular Weight ◽  
Ethylene Oxide ◽  
Parallel Plate ◽  
Average Molecular Weight ◽  
Radical Reaction ◽  
Free Radical Reaction ◽  
Nitrogen Gas ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene ◽  
Initial Viscosity

Aqueous solutions of a 1 weight-per cent poly (ethylene oxide) (PEO) were degassed under vacuum, transferred to a parallel plate viscometer under a nitrogen gas blanket, and exposed to Co60 gamma radiation. The Co60 source was rated at 4000 curies, and the dose ratewas 3.8x105 rads/hr. The poly (ethylene oxide) employed in the irradiations had an initial viscosity average molecular weight of 2.1 x 106.The solutions were gelled by a free radical reaction with dosages ranging from 5x104 rads to 4.8x106 rads.

Preparation of Organized Mesoporous Silica from Sodium Metasilicate Solutions in Alkaline Medium Using Nonionic Surfactants

2003 ◽  
Vol 68 (10) ◽  
pp. 2019-2031 ◽  
Author(s):  
Markéta Zukalová ◽  
Jiří Rathouský ◽  
Arnošt Zukal
Keyword(s):  
Mesoporous Silica ◽  
Ethylene Oxide ◽  
Sodium Metasilicate ◽  
Spherical Particles ◽  
Structure Directing Agent ◽  
Inorganic Species ◽  
Poly Ethylene Oxide ◽  
Acidic Conditions ◽  
Poly Ethylene ◽  
Hydrolysis Of

A new procedure has been developed, which is based on homogeneous precipitation of organized mesoporous silica from an aqueous solution of sodium metasilicate and a nonionic poly(ethylene oxide) surfactant serving as a structure-directing agent. The decrease in pH, which induces the polycondensation of silica, is achieved by hydrolysis of ethyl acetate. Owing to the complexation of Na+ cations by poly(ethylene oxide) segments, assembling of the mesostructure appears to occur under electrostatic control by the S0Na+I- pathway, where S0 and I- are surfactant and inorganic species, respectively. As the complexation of Na+ cations causes extended conformation of poly(ethylene oxide) segments, the pore size and pore volume of organized mesoporous silica increase in comparison with materials prepared under neutral or acidic conditions. The assembling of particles can be fully separated from their solidification, which results in the formation of highly regular spherical particles of mesoporous silica.

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