pH-Induced Release of Polyanions from Multilayer Films

Journal Article · Tue Jan 01 00:00:00 EST 2008 · Physical Review Letters

DOI:https://doi.org/10.1103/PhysRevLett.100.128303· OSTI ID:931143

Kharlampieva, Dr. Eugenia ^[1]; Ankner, John Francis ^[2]; Rubinstein, Michael ^[3]; Sukhishvili, Prof. Svetlana A. ^[1]

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1. Stevens Institute of Technology, Hoboken, New Jersey
2. ORNL
3. University of North Carolina, Chapel Hill

We discovered pH-induced selective desorption and re-adsorption of weak polyacid chains from polyacid/polybase layer-by-layer films. In situ ATR-FTIR 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, τ, scales with molar mass, Mw, as Mw1.1 0.1. A new theoretical model of "sticky gel electrophoresis" of entangled polyacids agrees with experiments and predicts τ ~ Mw H, where H is film thickness. Neutron reflectivity shows that polyacid release results in disordering of the film structure.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 931143
• Journal Information: Physical Review Letters, Vol. 100, Issue 12; ISSN 0031-9007
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
CHAINS
DESORPTION
ELECTROPHORESIS
NEUTRONS
REFLECTIVITY
THICKNESS
FILMS
poly-electrolyte
neutron reflectivity
controlled release