TY  - JOUR
A1  - Fechner, Mabya
A1  - Koetz, Joachim
T1  - Polyampholyte-Surfactant film tuning in reverse microemulsions
JF  - Langmuir
N2  - The pH-dependent influence of two different strongly alternating copolymers [poly(N,N'-diallyl-N,N'-dimethylammonium-alt-N-phenylmaleamic carboxylate) (PalPh) and poly(N,N'-diallyl-N,a-dimethylammonium-alt-3,5-bis(carboxyphenyl) maleamic carboxylate) (PalPhBisCarb)] based on N,N'-diallyl-N, -dimethylarnmonium chloride and maleamic acid derivatives on the phase behavior of a water-in-oil (w/o) microemulsion system made from toluene pentanol (1:1) and sodium dodecyl sulfate was investigated. It was shown that the optically dear phase range can be extended after incorporation of these copolymers, leading to an increased water solubilization capacity. Additionally, the required amount of surfactant to establish a clear w/o microemulsion depends on the pH value, which means the hydrophobicity of the copolymers. Conductivity measurements show that droplet droplet interactions in the w/o microemulsion are decreased at acidic but increased at alkaline pH in the presence of the copolymers. From differenctial scanning calorimetry measurements one can further conclude that these results are in agreement with a change of the position of the copolymer in the interfacial region of the surfactant film. The more hydrophobic PalPh can be directly incorporated into the surfactant film, whereas the phenyl groups of PalPhBisCarb flip into the water core by increasing the pH value.
Y1  - 2011
U6  - https://doi.org/10.1021/la200791k
SN  - 0743-7463
VL  - 27
IS  - 9
SP  - 5316
EP  - 5323
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Fechner, Mabya
A1  - Koetz, Joachim
T1  - Potentiometric behavior of Polyampholytes based on N,N'-diallyl-N,N'-dimethylammonium chloride and maleamic acid derivatives
JF  - Macromolecular chemistry and physics
N2  - Strongly alternating copolymers (PalH, PalPh, PalPhBisCarb) composed of N,N'-diallyl-N,N'-dimethyl-ammonium chloride (DADMAC) and maleamic acid derivatives (MAD) are synthesized by a water-based free radical copolymerization using 4,4-azobis(4-cyanovaleric acid) (V501) as the initiator. The structure of the copolymers is verified by 1H-NMR, elemental analysis, and thermogravimetric measurements, and the physicochemical properties are investigated by viscometric and potentiometric techniques. Potentiometric titration curves show that the acidity of the carboxylic groups strongly depends on the degree of dissociation and the ionic strength. Since all copolymers behave as polycations at low degree of dissociation, a transition from an extended chain to a coil conformation can be identified by reaching the isoelectric point (IEP).
KW  - acidity constants
KW  - radical polymerization
KW  - polyampholytes
KW  - viscosity
KW  - conformational transitions
Y1  - 2011
U6  - https://doi.org/10.1002/macp.201100532
SN  - 1022-1352
VL  - 212
IS  - 24
SP  - 2691
EP  - 2699
PB  - Wiley-Blackwell
CY  - Malden
ER  -