Biomineralization of Calcium Phosphate and Calcium Carbonate within Iridescent Chitosan/Iota-Carrageenan Multilayered Films

This work systematically explores the biomineralization of calcium phosphate (CaP) and carbonate (CaCO₃) within chitosan/iota-carrageenan multilayer films. Multilayer films of chitosan and iota-carrageenan (up to 128-coupled layers) were prepared on glass substrates by a layer-by-layer dip-coating technique. Cryo-scanning electron microscopy revealed dense interfaces between the chitosan and iota-carrageenan layers with thicknesses in the range 250 and 350 nm in the hydrated state, accounting for the iridescent nature of multilayer films when wet. Immersion of the multilayered films in simulated body fluid or simulated seawater at 25 °C resulted in the mineralization of CaP and CaCO₃, respectively, at the interfaces between the biopolymer layers and modified the iridescence of the films. Lamellar scattering features in small-angle neutron scattering measurements of the mineralized films provided evidence of the localized mineralization. Further evidence of this was found through the lack of change in the dynamic and static correlation lengths of the polymer networks within the bulk phase of the chitosan and iota-carrageenan layers. CaP mineralization occurred to a greater extent than CaCO₃ mineralization within the films, evidenced by the higher lamellar density and greater rigidity of the CaP-mineralized films. Results provide valuable new insights into CaP and CaCO₃ biomineralization in biopolymer networks

Structure of [C₄mpyr][NTf₂] Room-Temperature Ionic Liquid at Charged Gold Interfaces

The structure of 1-butyl-1-methylpyrrolidinium bis­(trifluoromethylsulfonyl)­imide ([C₄mpyr]­[NTf₂]) room-temperature ionic liquid at an electrified gold interface was studied using neutron reflectometry, cyclic voltammetry, and differential capacitance measurements. Subtle differences were observed between the reflectivity data collected on a gold electrode at three different applied potentials. Detailed analysis of the fitted reflectivity data reveals an excess of [C₄mpyr]⁺ at the interface, with the amount decreasing at increasingly positive potentials. A cation rich interface was found even at a positively charged electrode, which indicates a nonelectrostatic (specific) adsorption of [C₄mpyr]⁺ onto the gold electrode

Structure of [C₄mpyr][NTf₂] Room-Temperature Ionic Liquid at Charged Gold Interfaces

The structure of 1-butyl-1-methylpyrrolidinium bis­(trifluoromethylsulfonyl)­imide ([C₄mpyr]­[NTf₂]) room-temperature ionic liquid at an electrified gold interface was studied using neutron reflectometry, cyclic voltammetry, and differential capacitance measurements. Subtle differences were observed between the reflectivity data collected on a gold electrode at three different applied potentials. Detailed analysis of the fitted reflectivity data reveals an excess of [C₄mpyr]⁺ at the interface, with the amount decreasing at increasingly positive potentials. A cation rich interface was found even at a positively charged electrode, which indicates a nonelectrostatic (specific) adsorption of [C₄mpyr]⁺ onto the gold electrode

Structure of [C₄mpyr][NTf₂] Room-Temperature Ionic Liquid at Charged Gold Interfaces

The structure of 1-butyl-1-methylpyrrolidinium bis­(trifluoromethylsulfonyl)­imide ([C₄mpyr]­[NTf₂]) room-temperature ionic liquid at an electrified gold interface was studied using neutron reflectometry, cyclic voltammetry, and differential capacitance measurements. Subtle differences were observed between the reflectivity data collected on a gold electrode at three different applied potentials. Detailed analysis of the fitted reflectivity data reveals an excess of [C₄mpyr]⁺ at the interface, with the amount decreasing at increasingly positive potentials. A cation rich interface was found even at a positively charged electrode, which indicates a nonelectrostatic (specific) adsorption of [C₄mpyr]⁺ onto the gold electrode

Structure of [C₄mpyr][NTf₂] Room-Temperature Ionic Liquid at Charged Gold Interfaces

The structure of 1-butyl-1-methylpyrrolidinium bis­(trifluoromethylsulfonyl)­imide ([C₄mpyr]­[NTf₂]) room-temperature ionic liquid at an electrified gold interface was studied using neutron reflectometry, cyclic voltammetry, and differential capacitance measurements. Subtle differences were observed between the reflectivity data collected on a gold electrode at three different applied potentials. Detailed analysis of the fitted reflectivity data reveals an excess of [C₄mpyr]⁺ at the interface, with the amount decreasing at increasingly positive potentials. A cation rich interface was found even at a positively charged electrode, which indicates a nonelectrostatic (specific) adsorption of [C₄mpyr]⁺ onto the gold electrode