scholarly journals Studies of Some Properties and the Structure of Polyethylene Glycol (PEG) Macromolecules Adsorbed on a TiO2 Surface

2001 ◽  
Vol 19 (5) ◽  
pp. 397-407 ◽  
Author(s):  
S. Chibowski ◽  
M. Paszkiewicz
Keyword(s):  
Molecular Weight ◽  
Polyethylene Glycol ◽  
Zeta Potential ◽  
Surface Charge ◽  
Adsorption Layer ◽  
Bulk Solution ◽  
Ionic Structure ◽  
Solution Interface ◽  
Main Factors ◽  
Presence And Absence

In the studies presented, the influence of the molecular weight of polyethylene glycol (PEG) on the adsorption and electrical properties at the metal oxide/polymer solution interface has been determined. The main factors responsible for the observed changes in the zeta potential and surface charge of titania were determined on the basis of the data obtained. It was demonstrated that changes in the ionic structure of the Stern layer depend on the molecular weight of PEG and its conformation. A possible mechanism for the changes in zeta potential both with pH and molecular weight was proposed on the basis of values of the surface charge difference (Δσ0) and the diffuse layer charge difference (Δσd) as determined in the presence and absence of the polymer. The thickness of the adsorption layer (δ) on the surface of titania was calculated from the zeta potential changes, both in the presence and absence of the polymer. A distinct influence of the PEG molecular weight was noted on the values of the adsorption layer thickness (δ) determined. The structures of the macromolecules in solution and at the solid/solution interface were compared and from the dependencies obtained some changes in the shape and dimensions of the polymer coils on passing from the bulk solution to the interface were proposed.

scholarly journals Adsorption of Polyelectrolytes at the Manganese Oxide(IV)–Polymer Solution Interface: Structure of Adsorbed Layers

2002 ◽  
Vol 20 (5) ◽  
pp. 511-522 ◽  
Author(s):  
S. Chibowski ◽  
M. Wiśniewska ◽  
M. Paszkiewicz
Keyword(s):  
Molecular Weight ◽  
Zeta Potential ◽  
Manganese Oxide ◽  
Polymer Solution ◽  
Adsorption Layer ◽  
Interface Structure ◽  
Ionic Polymers ◽  
Free Energies ◽  
Solution Interface ◽  
Adsorbed Layers

The influence of the molecular weight of polyelectrolytes on their adsorption and on the structure of the adsorbed layers at the manganese oxide(IV)–polymer solution interface was determined. Polyacrylic acid (PAA) and polyacrylamide (PAM) were applied as ionic polymers. An explanation was proposed for the observed changes in surface charge and zeta potential of the solid in the presence of these polymers. The thickness of the adsorption layer of PAA and PAM was determined and the free energies of adsorption of these polymers on the MnO2 surface were calculated from the zeta potential measurements.

scholarly journals Study of the Adsorption Mechanism and the Structure of Adsorbed Layers of Polyelectrolytes at the Metal Oxide/Solution Interface

2001 ◽  
Vol 19 (5) ◽  
pp. 409-421 ◽  
Author(s):  
S. Chibowski ◽  
M. Wiśniewska
Keyword(s):  
Molecular Weight ◽  
Zeta Potential ◽  
Metal Oxide ◽  
Polymer Adsorption ◽  
Solid Particles ◽  
Polymer Molecular Weight ◽  
Oh Groups ◽  
Solution Interface ◽  
Adsorbed Polymer ◽  
Principal Factors

The influence of the molecular weight of polyacrylic acid (PAA) and polyacrylamide (PAM) as well as of inorganic contaminants on the ZrO2 surface on the adsorption and electrokinetic properties of the metal oxide/polyelectrolyte solution interface were studied for ZrO2 and Fe2O3 solid particles. The calculated concentrations of the various surface groups on ZrO2 and Fe2O3 enabled an investigation of the possible mechanism for the bonding of the studied polyelectrolytes with the surfaces of both oxides. PAA and PAM macromolecules bond with the solid surface mainly via the –OH groups of the oxides, which may interact with the carboxy groups of polyelectrolytes through hydrogen bridging. A comparison of the change in values of the diffuse layer charge with the surface charge enabled the principal factors responsible for the changes in the zeta potential of the oxides, e.g. pH, polymer molecular weight and concentration of the polymer solutions, to be evaluated. From such zeta potential values, it was possible to determine the free energies of adsorption of PAA and PAM on the surfaces of both oxides. The thicknesses of adsorbed polymer layers on Fe2O3 and ZrO2 were calculated on the basis of measurements of their suspension viscosities in the absence and presence of adsorbed polymer. It was shown that the thickness of the adsorption layer increased with increasing polymer molecular weight, pH and concentration of the polymer solution. Because the experimental determination of the number and the length of trains, loops and tails in such polyelectrolytes was not possible, the participation of such segments of polymer structure at the interface was computed using the Scheutjens–Fleer model of polymer adsorption. The polymer adsorption expressed as the number of equivalent monolayers was calculated and compared with the experimental data.

Adsorption at solid-liquid interfaces. II. Models of the electrical double layer at the oxide-solution interface

1973 ◽  
Vol 26 (6) ◽  
pp. 1191 ◽  
Author(s):  
HJL Wright ◽  
RJ Hunter
Keyword(s):  
Zeta Potential ◽  
Surface Charge ◽  
Double Layer ◽  
Liquid Interfaces ◽  
Nernst Equation ◽  
Oxide Systems ◽  
Solution Interface ◽  
Gel Layer ◽  
Solid Liquid ◽  
Mineral Oxide Surfaces

An extension has been made to Gouy-Stern-Grahame models of the double layer on mineral oxide surfaces.1 In this work and an earlier paper,2 the Stern isotherm is used for adsorption of p.d. ions at the surface. This is essentially an inversion of the modified Nernst equation given by Levine and Smith.3 The development of the surface charge and potential is considered by two different but related methods. Comprehensive calculations show that the zeta potential of oxide systems may be reasonably simulated with such models but the calculated surface charge is much less than that found experimentally. It is suggested that a model in which this surface charge is incorporated into a gel layer may be more appropriate.

The oxide-solution interface

1974 ◽  
Vol 27 (3) ◽  
pp. 461 ◽  
Author(s):  
JW Perram ◽  
RJ Hunter ◽  
HJL Wright
Keyword(s):  
Surface Layer ◽  
Zeta Potential ◽  
Surface Charge ◽  
General Feature ◽  
Dissociation Constants ◽  
Strong Support ◽  
Thin Surface Layer ◽  
High Charge ◽  
Solution Interface ◽  
Gel Layer

We extend previous treatments of the gel model of the oxide-solution interface and solve exactly the most general soluble case, of such an oxide in the presence of a 1 : 2-2 : 1 electrolyte, for the distribution of charge and potential across the interface. We calculate values of the surface charge and zeta potential of the oxides TiO2, Fe2O3, SiO2 and M203 using reasonable values of adsorption potentials and dissociation constants taken from tables. We find, for the samples of such oxides for which high measured charges have been reported, that we can account quantitatively for all the data by characterizing the interface by a gel layer of thickness 20-40�. We infer that such comprehensive agreement, and the consistency in all cases of the high charge and low zeta potential with the theory, gives strong support to the view that a thin surface layer distorted by the penetration of water and all types of ions is a general feature of the oxide-solution interface.

Europium and cerium extraction by the nitrobenzene solution of dicarbolide in the presence of polyethylene glycols

1986 ◽  
Vol 51 (3) ◽  
pp. 498-515 ◽  
Author(s):  
Emanuel Makrlík ◽  
Petr Vaňura
Keyword(s):  
Molecular Weight ◽  
Polyethylene Glycol ◽  
Organic Phase ◽  
Perchloric Acid ◽  
Equilibrium Constants ◽  
Polyethylene Glycols ◽  
Individual Species ◽  
Nitrobenzene Solution ◽  
Separation Factors ◽  
Equilibrium Data

Extraction of Eu3+ and Ce3+ microamounts from 0.1-0.4M perchloric acid by the nitrobenzene solution of dicarbolide H+[Co(C2B9H11)2]- in the presence of polyethylene glycols (Mr = 200, 300, 400) has been studied. The equilibrium data and the typical maxima on the dependence of the metal distribution ratio on the total analytical concentration of polyethylene glycol in the system can be explained assuming that the species ML3+org, ML3+2org, ML3+3org, MLH2+-1org, and HL+org (where M3+ = Eu3+, Ce3+; L = polyethylene glycol) are extracted into the organic phase. The values of extraction and equilibrium constants in the organic phase were determined and the effect of the polyethylene glycol molecular weight on the equilibrium constants and on the abundances of individual species in the organic phase is discussed. It has been found that the addition of polyethylene glycol to the acid - nitrobezene - dicarbolide system increases the values of the separation factors αCe/Eu.

scholarly journals ‘Tanned’ gelatin spheres and granules for exclusion chromatography

1968 ◽  
Vol 108 (4) ◽  
pp. 641-646 ◽  
Author(s):  
A. Polson ◽  
W. Katz
Keyword(s):  
Molecular Weight ◽  
Polyethylene Glycol ◽  
High Molecular Weight ◽  
Weight Fraction ◽  
High Flow ◽  
High Molecular Weight Fraction ◽  
Flow Rates ◽  
Protein Molecules ◽  
Exclusion Chromatography

1. The preparation of tanned gelatin spheres and granules from high-molecular-weight gelatin is described. This material is comparatively hard, giving high flow rates, is insoluble in water at temperatures between 0° and 100° and is resistant to digestion by trypsin and chymotrypsin. The high-molecular-weight fraction of gelatin was prepared by precipitation with polyethylene glycol, and the spheres and granules prepared from this fraction were hardened and insolubilized by tanning with either formalin or chromium salts or both. 2. The spheres and granules were used successfully for the separation of protein molecules and other protein-aceous materials ranging in molecular weight from 200 to greater than 6000000. This gel exclusion material has several properties superior to those of other products used for similar purposes. Further, it was noticed that the porosity of the spheres differed considerably from that of the granules.

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