TY  - JOUR
A1  - Kristen-Hochrein, Nora
A1  - Laschewsky, André
A1  - Miller, Reinhard
A1  - von Klitzing, Regine
T1  - Stability of foam Films of oppositely charged polyelectrolyte/surfactant mixtures - effect of isoelectric point
JF  - The journal of physical chemistry : B, Condensed matter, materials, surfaces, interfaces & biophysical chemistry
N2  - In the present paper, the influence of the surfactant concentration and the degree of charge of a polymer on foam film properties of oppositely charged polyelectrolyte/surfactant mixtures has been investigated. To verify the assumption that the position of the isoelectric point (IEP) does not change the character of the foam film stabilities, the position of the IEP of the polyelectrolyte/surfactant mixtures has been shifted in two different ways. Within the first series of experiments, the foam. film properties were studied using a fixed surfactant concentration of 3 x 10(-5) M in the mixture. Due to the low surfactant concentration, this is a rather dilute system. In the second approach, a copolymer of nonionic and ionic monomer units was Used to lower the charge density of the polymer. This gave rise to additional interactions between the polyelectrolyte and the surfactant, which makes the description of the foam film behavior more complex. In both systems, the same characteristics of the foam film stabilities were found: The foam film stability is reduced toward the IEP of the system, followed by a destabilization around the IEP., At polyelectrolyte concentrations above the IEP, foam films are very stable. However, the concentration range where unstable films were formed was rather broad, and the mechanisms leading to the destabilization had different origins. The results were compared with former findings on PAMPS/C(14)TAB mixtures with an IEP of 10(-4)M.(1)
Y1  - 2011
U6  - https://doi.org/10.1021/jp206964k
SN  - 1520-6106
VL  - 115
IS  - 49
SP  - 14475
EP  - 14483
PB  - American Chemical Society
CY  - Washington
ER  -