Preparation and Characterization of Japanese Ink-Inspired Aqueous Dispersions of Carbon Materials with the Help of Glue as Colloid Chemistry Teaching Aid

Abstract

Aqueous dispersions of soot and other carbon materials, prepared in a manner similar to that used for preparing traditional Japanese ink, were developed as teaching materials for colloid chemistry. The protective colloid formed by the addition of glue is an interesting teaching material that allows visual understanding of various colloidal phenomena. In addition, such dispersions can be prepared using glue and various carbon materials (e.g., pencil lead, barbecue charcoal, C60 fullerene, graphene, and carbon nanotubes), following an extremely simple and environmentally friendly method. The carbon materials are insoluble in water without the glue, highlighting the need for glue to act as a protective colloid in ink preparation. Herein, we describe convenient colloid chemistry experiments that are adaptable to a wide range of educational settings.

Introduction and Characterization of Simple Moisture-Driven Smart Paper for Chemistry Experiment in the Classroom: A Brief Guideline

“…As shown in Figure , the mixing of carbon soot/polyphenols suspension with bleach before filtration prevents the passing of nanosized soot through the paper, evidenced by the colorless appearance of the collected filtrate that consisted only of bleach and water. In comparison to the salting-out effect by sodium chloride in the previous work, the incorporation of sodium hypochlorite as an electrolyte into the colloidal suspension will produce precipitation of the electrically conductive soot due to the chemical degradation of tea polyphenols upon exposure to Cl radicals from bleach and not due to the lack of solubility for the soot after less interaction with water molecules . In related studies on the exposure effect of carbon nanotubes and graphene oxide to bleach, , the degradation of carbon in the presence of sodium hypochlorite was only triggered after an extreme exposure condition of both materials ( t > 7 h) while the sodium hypochlorite concentration was increased to 11% w/v at room temperature.…”

“…Therefore, we suggest the usage of electrically conductive candle soot as a coating material, which is produced from the incomplete combustion of a hydrocarbon in paraffin wax and easily harvested using a simple setup with household bleach as a solvent. We note the previous application of insulated carbon soot as an example substance model for the teaching of colloidal chemistry, optical, and wetting properties and never as ink for smart electronics paper to the best of our knowledge. We also noticed that despite the lack of work reporting on the dispersion of soot in the tea polyphenols to date, the stabilization of carbon-based materials such as graphene or carbon nanotube against reaggregation in this medium had already been previously reported in the literature and, thus, may serve as project reference for the students.…”

Synthesis of Japanese-Solid-Calligraphy Ink with Soot and Glue as a Xerogel Chemistry Teaching Aid

“…Using the carbon dispersion obtained by this method, various educational experiments could be performed to confirm several properties of colloids, such as Brownian motion, salting-out, the Tyndall phenomenon, and protective colloids. 22 Furthermore, the phenomenon of dialysis could be easily demonstrated by using this dispersion. In addition, the prepared dispersion of Japanese-solidcalligraphy ink (10.0 mL) was placed in a cellophane tube for dialysis, after which it was immersed in water in a 50 mL beaker and allowed to stand for 1 day.…”

“…26,27 Therefore, a wide particle size distribution was observed for the glue, ranging from 1 to 1000 nm. 22 Notably, the particle size distributions of the glue (dotted line) and solid ink dispersion (dotted line) were markedly different. Surface Observations with an Electron Microscope.…”

“…21,22 Our research group previously explored teaching materials comprising dispersed soot or liquid dispersions made from soot. 22 Therein, we developed educational material to study the properties of liquid colloidal dispersions, or sols, rather than solid xerogels. The other component, glue, is primarily composed of gelatin derived from animal skin and tendons.…”