title: Ion permeability of polydopamine films revealed using a Prussian blue-based electrochemical method.
abstract: Polydopamine (PDA) is fast becoming a popular surface modification technique. Detailed understanding of the ion permeability properties of PDA films will improve their applications. Herein, we report for the first time the thickness-independent ion permeability of PDA films using a Prussian blue (PB)-based electrochemical method. In this method, PDA films are deposited via ammonium persulfate-induced dopamine polymerization onto a PB electrode. The ion permeability of the PDA films can thus be detected by observing the changes in electrochemical behaviors of the PB coated by PDA films. On the basis of this method, it was unexpectedly found that the PDA films with thickness greater than 45 nm (e.g., ~60 and ~113 nm) can exhibit pH-switchable but thickness-insensitive permeability to monovalent cations such as potassium and sodium ions. These observations clearly indicate the presence of a continuous network of interconnected intermolecular voids within PDA films, regardless of film thickness.
authors.affiliation: Research Center for Bioengineering and Sensing Technology, University of Science and Technology Beijing , Beijing 100083, China.
authors.forename: Bowen
authors.initials: B
authors.lastname: Gao
authors.forename: Lei
authors.initials: L
authors.lastname: Su
authors.forename: Ying
authors.initials: Y
authors.lastname: Tong
authors.forename: Miao
authors.initials: M
authors.lastname: Guan
authors.forename: Xueji
authors.initials: X
authors.lastname: Zhang
mesh_terms: D000645:Ammonium Sulfate / Q000737:chemistry; D002414:Cations, Monovalent; D055664:Electrochemical Techniques; D004566:Electrodes; D005295:Ferrocyanides / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007211:Indoles / Q000737:chemistry*; D008567:Membranes, Artificial; D010539:Permeability; D011108:Polymers / Q000737:chemistry*; D011188:Potassium / Q000737:chemistry*; D012964:Sodium / Q000737:chemistry*
chemical_list: D002414:Cations, Monovalent; D005295:Ferrocyanides; D007211:Indoles; D008567:Membranes, Artificial; D011108:Polymers; C568283:polydopamine; C031276:ammonium peroxydisulfate; D012964:Sodium; D011188:Potassium; D000645:Ammonium Sulfate; C000170:ferric ferrocyanide