TY - JOUR
T1 - Adsorption of polyampholyte copolymers at the solid/liquid interface
T2 - The influence of pH and salt on the adsorption behaviour
AU - Mahltig, Boris
AU - Walter, Harald
AU - Harrats, Charef
AU - Müller-Buschbaum, Peter
AU - Jérôme, Robert
AU - Stamm, Manfred
PY - 1999/9/1
Y1 - 1999/9/1
N2 - Polyampholytes are macromolecules that contain oppositely charged groups. We have studied the adsorption of the polyampholyte diblock copolymer poly(methacrylic acid)-block-poly((dimethylamino)ethyl methacrylate), PMAA-b- PDMAEMA, on oxidized silicon surfaces. The amount of polymer adsorbed from aqueous solution of different pH and salt concentration was measured by ellipsometry. The influence of the added salts NaCl, Na2SO4 and CaCl2 was determined. In every case adsorption took place, although the polyampholyte and the substrate exhibit the same sign of net charge. For all types of salt, the adsorbed amount shows two maxima close to the isoelectric point (IEP) of the polymer as a function of pH. Directly at the IEP of the polyampholyte, no adsorption was found. The measured dependences can be explained by the adsorption of one or the other of the two blocks depending on acidity and ionic strength. Furthermore, the lateral structure of the dried films was investigated by scanning force microscopy (SFM).
AB - Polyampholytes are macromolecules that contain oppositely charged groups. We have studied the adsorption of the polyampholyte diblock copolymer poly(methacrylic acid)-block-poly((dimethylamino)ethyl methacrylate), PMAA-b- PDMAEMA, on oxidized silicon surfaces. The amount of polymer adsorbed from aqueous solution of different pH and salt concentration was measured by ellipsometry. The influence of the added salts NaCl, Na2SO4 and CaCl2 was determined. In every case adsorption took place, although the polyampholyte and the substrate exhibit the same sign of net charge. For all types of salt, the adsorbed amount shows two maxima close to the isoelectric point (IEP) of the polymer as a function of pH. Directly at the IEP of the polyampholyte, no adsorption was found. The measured dependences can be explained by the adsorption of one or the other of the two blocks depending on acidity and ionic strength. Furthermore, the lateral structure of the dried films was investigated by scanning force microscopy (SFM).
UR - http://www.scopus.com/inward/record.url?scp=0033199428&partnerID=8YFLogxK
U2 - 10.1039/a903395e
DO - 10.1039/a903395e
M3 - Article
AN - SCOPUS:0033199428
SN - 1463-9076
VL - 1
SP - 3853
EP - 3856
JO - Physical Chemistry Chemical Physics
JF - Physical Chemistry Chemical Physics
IS - 17
ER -