Temperature Study of Nonionic Polymers Adsorption at the Alumina—Solution Interface

Abstract

The temperature influence of the structures of polyvinyl alcohol (PVA) and polyethylene glycol (PEG) adsorption layers on the alumina surface was studied. The amount of polymer adsorbed, the surface and diffuse layer charge of Al 2 O 3 particles in the absence and presence of the polymer, and the thickness of polymer adsorption layers were determined in the 51-401C temperature range. An increase of PVA and PEG adsorption with an increase of temperature was observed. It is caused by conformation changes of polymer macromolecules from the coil structure to more and more stretched conformation when the temperature increases. Such a behavior was confirmed by the parameters calculated from the experimental data (R h -hydrodynamic radius of a polymer coil in the solution, d-thickness of the polymer adsorption layer, R s -radius of a sphere equivalent to the volume that falls per a macromolecule in the adsorbed layer). From the comparison of the values of diffuse layer charge and surface charge, the main factor influencing the f potential changes was determined. The free energy of PVA and PEG adsorption was calculated using the f potential data.

Adsorption and thermodynamic properties of the alumina–polyacrylic acid solution system

“…The estimation of the free energy of adsorption of PAA segments on alumina is based on the adsorption-desorption measurements. These investigations are the continuation and supplement of our previous studies [6,7]. All measurements (adsorption-desorption, solid surface charge density, viscosity and spectrophotometric) were carried out in the temperature range 15-35°C.…”

Influences of polyacrylic acid adsorption and temperature on the alumina suspension stability

“…Table 1 shows the parameters characterizing PAA macromolecules conformation in the solution and its adsorbed layers on the Al 2 O 3 surface at different temperatures. These data were presented in detail in previous papers [5][6][7] and in the present manuscript the most important of them were compiled in the form of a table. The analysis of the data in Table 1 is very important for explanation of the obtained results from the stability measurements.…”

“…Additionally, at 25°C the suspension stability was determined using a spectrophotometer Specord M52 from the absorbance changes. This study is the continuation and kind of supplement of the previous studies concerning the temperature influence on the adsorbed amounts, polymer layer thicknesses and free energies of PAA adsorption on the alumina surface [5][6][7].…”

Interactions between kappa-carrageenan and some surfactants in the bulk solution and at the surface of alumina

“…In order to avoid the influence of the temperature on the amount of polymer adsorption all measurements were conducted at the same temperature 25 • C (Wiśniewska, 2007(Wiśniewska, , 2010.…”