Hydrophobic and ionic exchange of tris(2,2'-bipyridine)ruthenium(II), methylviologen, and sulfonatopropylviologen in Nafion films

Emission of Thioflavin T and its Off–On Control in Polymer Membranes‡¶

“…The diffusion coefficient (D) determined from the above plot is 6.9 ϫ 10 Ϫ11 cm 2 s Ϫ1 for Na ϩ -Nf/TFT ϩ , and the value is comparable with the values obtained for other dye molecules (30). The free energy of hydrophobic interaction of TFT ϩ ( ) with the Nafion membrane was calculated by a re-0 ⌬G h ported procedure (35,36). The exchange of monovalent metal ions (Na ϩ ) in the presence of TFT ϩ was studied (Eqs.…”

“…The standard free energy of hydrophobic interaction of TFT ϩ with the Nafion membrane calculated is Ϫ4.3 Ϯ 0.1 kcal mol Ϫ1 . This value is almost equal to the value reported for MV 2ϩ (Ϫ4.6 Ϯ 0.2 kcal mol Ϫ1 ) (35) and smaller than the value reported for phenothiazine dyes (36). These results indicate that the TFT ϩ molecules diffuse into the membrane and are immobilized into the microenvironment of Nafion.…”

“…It is assumed that the TFT ϩ molecules have both electrostatic and hydrophobic interactions with the Nafion membrane, whereas the inorganic ion (Na ϩ ) has only an electrostatic interaction. The electrostatic interaction of the Na ϩ ion with the Nafion membrane remains constant while exchanging monovalent inorganic ions for monovalent organic cat-ions (35). The standard free energy of hydrophobic interaction of dyes with Nafion is given by Eq.…”

Electrochemical characterisation and comparison of transport in Nafion films and particles

“…The interaction between the redox species and Nafion is both ionic and hydrophobic for methyl viologens. 28 In comparison to MV 2+ , MV + is more hydrophobic and this is a possible reason explaining why MV + moves slower in the water-saturated Nafion film. 29…”

Metal–Organic Frameworks Toward Electrocatalytic Applications

“…For electrocatalytic applications, the design of thin-film electrocatalysts thus becomes crucial to achieve a faster reaction rate at a relatively lower overpotential. The reaction rate of the thin-film electrochemical process can be affected by the following factors [10][11][12]: (1) the total number of electrochemically active sites presented in the entire thin film, (2) the charge-transport rate between those active sites and from the active sites to the underlying electrode, (3) the rate of physical diffusion of the active sites within the film (if there is any), and (4) the diffusivity of counter ions within the thin film for maintaining electroneutrality. The total number of electrochemically active sites is directly related to the accessible surface area of the thin film deposited on the electrode.…”