Electrolysis Electrode for Conductivity

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The primary purpose of these designs is outlined in "Electrolysis Activation of Fused Filament Fabrication 3D Printed Electrodes for Electrochemical and Spectroelectrochemical Analysis," which was published in the journal Analytical Chemistry. The article's DOI is 10.1021/acs.analchem.9b01331. This particular design modifies the "Electrolysis Electrode" with a square end for four-point probe conductivity experiments. The square base can be easily removed after activating the electrode through electrolysis. We have printed this part using both ProtoPasta (https://www.proto-pasta.com/products/conductive-pla) and BlackMagic (http://www.blackmagic3d.com/default.asp) PLA-composite 3D printing filaments. Details regarding conductivity enhancement can be found in post-printing information. Electrode activation through electrolysis is recommended. To perform the electrolysis process, 7.5 mL of a 1M salt solution was added to both sides of the "electrolysis cell." Electrochemical connection between the compartments was maintained using an approximately 1 cm^2 section of paper towel dipped in the electrolyte of both compartments. Electrolysis was performed using a 9V battery. Connection from the battery to the electrodes was accomplished using commercial 9V battery snap connectors with alligator clips. Note that the negative terminal, typically the black wire, connects to the compartment that becomes more alkaline and therefore more conductive. The same time ranges apply here. Due to acid/base chemistry in either compartment, waste solution from both compartments can be mixed and safely poured down the drain. Please exercise caution when using batteries around liquids. 9V batteries used in our research were purchased from Amazon: https://www.amazon.com/AmazonBasics-Everyday-Alkaline-Batteries-8-Pack/dp/B00MH4QM1S. Battery snap connectors with alligator clips can also be found on Amazon: https://www.amazon.com/SDTC-Tech-Connector-Positive-Alligator/dp/B07NTH8VGH/ref=sr_1_2?keywords=battery+snap+connectors+with+alligator+clips&qid=1554746475&s=gateway&sr=8-2. For the salt solution, any salt will work fine. For common table salt (NaCl), 1 gram of salt makes approximately 17 mL of a 1M salt solution. Alternatively, 1 teaspoon of salt can be used to make approximately 95 mL (3.2 fl oz) of a 1M salt solution. Electrode activation using hydroxide solution is also possible. For the soaking process, 10 mL of a 4M hydroxide solution can be used. The optimal time for this electrode was found to be 6-24 hours when using BlackMagic Filament and 24-72 hours when using ProtoPasta filament. In our studies, we used sodium hydroxide, which can be purchased online: https://www.amazon.com/Sodium-Hydroxide-Pure-Grade-Caustic/dp/B06W57NL8S/ref=sr_1_3?keywords=sodium+hydroxide&qid=1554747032&s=gateway&sr=8-3. Note that high concentrations of hydroxide are corrosive and should be handled with care. To prepare a 4M solution, mix 16 grams NaOH with approximately 100 mL of water. This is an exothermic process and should be performed in a well-ventilated area. The 3D printed objects were designed using SketchUp Make 2017, available free from Google: http://www.sketchup.com/. Designs were sliced using Cura for Lulzbot: https://www.lulzbot.com/cura, a free software based on the more universal Cura software from Ultimaker: https://ultimaker.com/en/products/cura-software.