pH-induced release of polyanions from multilayer films.
We discovered pH-induced selective desorption and readsorption of weakly acidic polymers from polyacid or polybase layer-by-layer films. In situ attenuated total reflection Fourier transform infrared spectroscopy confirms the selectivity of polyacid release and shows that film response is caused by pH-induced charge imbalance. Experimentally the characteristic time of chain release tau scales with molar mass M as M(1.1+/-0.1). A new theoretical model of "sticky gel electrophoresis" of entangled polyacids agrees with experiments and predicts tau approximately MH, where H is film thickness. Neutron reflectivity shows that polyacid release results in disordering of the film structure.
Kharlampieva
Eugenia
E
Department of Chemistry and Chemical Biology, Stevens Institute of Technology, Hoboken, New Jersey 07030, USA.
Ankner
John F
JF
Rubinstein
Michael
M
Sukhishvili
Svetlana A
SA
D006863:Hydrogen-Ion Concentration; D011073:Polyamines / Q000737:chemistry; D000071228:Polyelectrolytes; D011108:Polymers / Q000737:chemistry*; D011109:Polymethacrylic Acids / Q000737:chemistry*; D011145:Polyvinyls / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D055672:Static Electricity
D011073:Polyamines; D000071228:Polyelectrolytes; D011108:Polymers; D011109:Polymethacrylic Acids; D011145:Polyvinyls; C030613:polymethacrylic acid; C019535:poly(4-vinylpyridine)