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Adsorption of poly(vinyl formamide‐ co ‐vinyl amine) onto silica particle surfaces and stability of the formed hybrid materials
Author(s) -
Bucatariu Florin,
Simon Frank,
Spange Stefan,
Schwarz Simona,
Dragan Stela
Publication year - 2004
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.200450625
Subject(s) - polyelectrolyte , polyelectrolyte adsorption , adsorption , formamide , chemical engineering , ionic strength , electrokinetic phenomena , aqueous solution , surface charge , chemistry , polymer chemistry , streaming current , materials science , inorganic chemistry , organic chemistry , polymer , engineering
In order to produce silica/polyelectrolyte hybrid materials the adsorption of the polyelectrolyte poly(vinyl formamide‐ co ‐vinyl amine), P(VFA‐ co ‐VAm) was investigated. The adsorption of the P(VFA‐ co ‐VAm) from an aqueous solution onto silica surface is strongly influenced by the pH value and ionic strength of the aqueous solution, as well as the concentration of polyelectrolyte. The adsorption of the positively charged P(VFA‐ co ‐VAm) molecules on the negatively charged silica particles offers a way to control the surface charge properties of the formed hybrid material. Changes in surface charges during the polyelectrolyte adsorption were studied by potentiometric titration and electrokinetic measurements. X‐ray photoelectron spectroscopy (XPS) was employed to obtain information about the amount of the adsorbed polyelectrolyte and its chemical structure. The stability of the adsorbed P(VFA‐ co ‐VAm) was investigated by extraction experiments and streaming potential measurements. It was shown, that polyelectrolyte layer is instable in an acidic environment. At a low pH value a high number of amino groups are protonated that increases the solubility of the polyelectrolyte chains. The solvatation process is able to overcompensate the attractive electrostatic forces fixing the polyelectrolyte molecules on the substrate material surface. Hence, the polyelectrolyte layer partially undergoes dissolving process.