2006/07/25 by J. Pittler, Jens Pittler, Wei Bu +9
Chemistry · Engineering · Physics and Astronomy · #Adsorption #Analytical Chemistry (journal) #Chemical physics #Chemistry #Chromatography #Electrode #Electrolyte #Electrostatics and Colloid Interactions #Ion #Materials science #Monolayer #Nanopore and Nanochannel Transport Studies #Nanotechnology #Overcharge #Physical chemistry #Physics #Saturation (graph theory) #Spectroscopy and Quantum Chemical Studies #Surface charge #Thermodynamics #cond-mat.soft
paper · pdf · doi:10.1103/physrevlett.97.046102
published as Physical Review Letters 97, 046102 (2006)
openalex publication_date 2006/07/25 · arxiv created 2006/07/31 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Anionic dimyristoylphosphatidic acid monolayers spread on LaCl3 solutions reveal strong cation adsorption and a sharp transition to surface overcharging at unexpectedly low bulk salt concentrations. We determine the surface accumulation of La3+ with anomalous x-ray reflectivity and find that La3+ compensates the lipid surface charge by forming a Stern layer with approximately 1 La3+ ion per 3 lipids below a critical bulk concentration, ct approximately 500 nM. Above ct, the surface concentration of La3+ increases to a saturation level with approximately 1 La3+ per lipid, thus implying that the total electric charge of the La3+ exceeds the surface charge. This overcharge is observed at approximately 4 orders of magnitude lower concentration than predicted in ion-ion correlation theories. We suggest that transverse electrostatic correlations between mobile ions and surface charges (interfacial Bjerrum pairing) may contribute to the charge inversion.