Electric conductivity measurements employing 3D printed electrodes and cells.

The electric conductivity is one the most routinely inspected characteristics of aqueous media, being employed in monitoring drinking water quality and determining thermodynamic properties of electrolytes. In this work, we utilize fused deposition modelling 3D printing (3DP) to manufacture a platform composed of supporting cells and sensing electrodes for electric conductivity measurements of aqueous solutions. For the first time, the electric conductivity of liquid electrolytes is sensed by 3DP electrodes, employing a direct electrode/electrolyte contact. Conductivity measurements performed in the presented 3DP platform are controlled by an electronic circuitry developed employing a programmable system on chip prototyping kit. The entire conductometric setup was validated employing commercial conductance standards as well as in-lab prepared aqueous solutions of potassium chloride and formic and acetic acid as representatives of strong and weak electrolytes. Conductivity measurements enabled the correct determination of limiting molar conductivity (for potassium chloride) and dissociation constants (for the two weak acids). Finally, the functionality of the presented platform was confirmed by measuring conductivity of various bottled water samples. Results obtained in this work pave the wave for further development and applications of conductometers based on 3DP electrodes and cells.

Electrochemical control of a non-covalent binding between ferrocene and beta-cyclodextrin.

The forces required for the detachment of ferrocene (Fc) from ß-cyclodextrin (ßCD) in a single host (ßCD)-guest (Fc) complex were investigated using force spectroscopy under electrochemical conditions. The redox state of the guest Fc moiety as well as the structure of the supporting matrix was found to decisively affect the nanomechanical properties of the complex.