Die Adsorption von Makromolekeln IV. Mehrschichtenadsorption von Polyäthylenglykolen

Abstract

zum 60. Geburtstag in Verehrung gewidmet (Eingegangen am 27. Juli 1962) ZUSAMMENFASSUNG:Mit Polyathylenglykolen der Molekulargewichte 1000-28 000 wurden Adsorptionsmessungen aus Losung durchgefiihrt. Die an Folien adsorbierte Menge wird durch Wagung bestimmt, ohne dabei einen Eingriff in das MeRsystem vorzunehmen. E s ergeben sich stufenformige Adsorptionsisothermen, deren Abhangigkeit von Temperatur und Molekulargewicht in verschiedenen Losungsmittel/Adsorbenssystemen zu interessanten Aufschliissen iiber die adsorbierte Schicht fiihren. Auf Grund des Auftretens von Stufen in der Adsorptionsisotherme ist fur Polyathylenglykole eine Adsorption in mehreren Schichten gegeben. Die GroBe der Adsorptionsenthalpie wird von der Bedeckung und der Schichtzahl beeinfluBt und gibt AufschluR iiber den Adsorptionsvorgang und die adsorbierte Schicht. SUMMARY:Adsorption measurements have been made with polyethylene glycol. The amount of adsorption on foils is determined by weighting without gearing in the measurement system.Step-like adsorption-isotherms result. The dependence or temperature and molecular weight in different solvent-adsorben systems give interesting information about the adsorbed layer. The appearance of steps in the adsorption-isotherm proves multilayer adsorption for polyethylene glycol. The enthalpy of adsorption, influenced by the number of the layer and the amount of adsorption, illuminates the mechanism of adsorption and the adsorbed layer.F. PATAT und Mitarbeiterl-3) haben kurzlich uber eine Methode be-

Polyacrylamide at Solid/Liquid Interfaces

“…In thermodynamic terms, polymer adsorption was treated like that of low-molecular-weight solutes, for which Langmuir-type kinetics and equilibria had been found to apply (5,6). Adsorption enthalpy was for example derived from the temperature dependence of adsorption isotherms (7)(8)(9). Killmann pointed out that this method might cause problems insofar as the conditions of isostericity and reversibility were not fulfilled in the case of polymer adsorption and showed that contradictory results were obtained using the Clausius-Clapeyron equation or direct measurements of adsorption enthalpy (10).…”

Adsorption of ionizable polymers on ionic surfaces: poly(acrylic acid)

“…Conformational distortion into a rather elongated state has been supported by experimental measurements19 of the fraction of functional groups attached to the surface (e.g., more than 30%). The effect of solution variables (solvent, temperature, and molecular weight) and nature of the substrate on amount adsorbed has also been investigated (e.g., see ref [20][21][22][23][24][25][26][27]. Even though there are exceptions, adsorption usually increases with molecular weight, and it is inversely proportional to solution intrinsic viscosity (it decreases with solvent power).…”