Exfoliation of Egyptian Blue and Han Blue, Two Alkali Earth Copper Silicate-based Pigments

The overall goal of this procedure is to prepare solution processable nano sheets of calcium, copper, tetra silicate, and barium copper tetra silicate materials. This is accomplished by first preparing the bulk materials by either solid state or melt flux roots. The second step is to exfoliate these layered materials into nano sheets by using heating or ultras sunation technique.

The final step is to disperse the nano sheets in water for solution processing. Ultimately, transmission electron microscopy is used to demonstrate the formation of alkali earth, copper tetra silicate, nano sheets and near infrared imaging shows the luminescent properties of both powder and solution process nano sheet samples. This method can provide insight into the factors that influence the formation and exfoliation of alkali earth, copper tetra silicates, and it also provides an easy way to process these materials.

Begin synthesizing calcium copper tetra silicate with the melt flux method by weighing out calcium carbonate silicon dioxide and basic copper carbonate in a two to eight to one molar ratio. In addition, weigh out the flux components of sodium carbonate, sodium chloride, and borax as 12.5%by weight of the other components. Put all of these materials in an egg eight mortar.

The mixture will initially appear like this. Use an egg eight pestle to hand grind the mixture for about five minutes. Stop when the mixture becomes a homogenous light green powder.

Then transfer this mixture to a clean, dry, platinum crucible. Next place the crucible in a furnace set and begin the appropriate heating and cooling cycle. This will take more than 40 hours.

After recovering the crystals from the oven, place them in the egg eight mortar gently crush them with a pestle. Next, transfer the crystals to a beaker. Prepare 50 milliliters of one molar aqueous hydrochloric acid.

Pour this into the vessel with the crystals. Allow the crystals to soak overnight to remove the melt flux. After at least 10 to 12 hours, filter out the crystals.

Remove any remaining melt flux by washing them with deionized water. The crystals can be stored in a vial for the solid state synthesis of calcium, copper, tetra silicate, weigh out calcium carbonate silicon dioxide and copper oxide. In a one to four to one molar ratio, add these to a clean egg.

Eight mortar. Dampen the powder mixture with one to two milliliters of acetone. Next hand, grind the mixture with an agate pestle for about five minutes.

Stop when it becomes a light gray powder. After transferring this powder to a platinum crucible, lace the crucible in a furnace and start the appropriate heating and cooling cycle. Once the cycle is complete, get the crucible and A-P-T-F-E spatula.

Use the spatula to scrape out the loose light blue powder into a vial to exfoliate calcium copper tetra silicate. Use a 50 milliliter round bottom flask. Add to it 0.50 grams of the crystals and 40 milliliters of deionized water.

Also, add a glass coated magnetic stir bar. Next, attach a water cooled condenser to the flask. Lace the flask on a heat source set to 85 degrees Celsius and a stir set at 400 RPM.

Maintain these conditions for two weeks. When two weeks have passed, remove the flask from the heat source and stir. Set the flask aside to allow the solution to settle.

The flask should be undisturbed overnight after it has settled. Remove the stir bar and filter the supernatant through a 0.4 micrometer membrane filter with vacuum filtration. Prepare an ink with the calcium copper tetra silicate by adding about 0.10 grams of the nano sheath to five milliliters of deionized water.

Place this in a bath ator. When about 10 minutes have passed, remove the container. The result is an ink that can be used for painting and printing to begin the melt flux synthesis of barium copper, tetra silicate, weigh out barium carbonate silicon dioxide and copper oxide in a one to four to one molar ratio.

Also weigh out 12.5%by weight of the flux component lead oxide. Add these materials to a clean agate mortar hand until the material becomes a light gray powder. At this point, transfer the mixture to a clean, dry, platinum crucible and place it in a furnace to begin a heating and cooling cycle.

After recovering the crystals from the crucible, gently crush them using a pestle to remove the melt flux. Transfer the crystals to a beaker and soak in 50 milliliters of one molar nitric acid. After soaking 10 to 12 hours, filter the crystals and wash with the ionized water to remove the remainder of the melt flux.

The solid state synthesis of barium copper tetra silicate starts with barium carbonate silicon dioxide and copper oxide in a one to four to one molar ratio in a clean egg, eight mortar, dampen the mixture with one to two milliliters of acetone. Grind the powder by hand until it is a light gray. Transfer the powder to a platinum crucible and place it in a furnace for its heating and cooling cycle.

When the cycle is over, use A-P-T-F-E spatula to scrape out the material. Store the loose blue powder in a vial exfoliation of barium copper tetra silicate begins with a 50 milliliter plastic centrifuge tube. Add 0.14 grams of the crystals and 20 milliliters of end vinyl perone with the tube immersed in an ice bath.

Use a probe ultrasonic ator at 17 watts to sonicate for one hour. After sonication, let the dispersion settle undisturbed overnight. Next, after 10 to 12 hours, decant the supernatant into a new centrifuge tube.

Use the centrifuge to spin down the contents at about 10, 300 G or 10 minutes. When the centrifuge step is over, remove the tube and decant the supernatant to leave nano sheets at the bottom of the centrifuge tube. To resuspend this material, add 20 milliliters of water.

Transfer the container to a bath, sonicate and sonicate it for a few minutes. Retrieve the container, filter the mixture through a 0.4 micrometer membrane filter and dry all of the materials can be imaged in the near infrared position a camera capable of imaging in the near infrared and set its F number to 22 and its exposure time to 0.5 seconds. Next, eliminate the samples with an LED array or other source of red light.

Eliminate other light sources and capture images of the sample. Here are low magnification, optical images of bulk calcium copper tetra silicate made by melt flux and by solid state synthesis. Next is bulk barium copper tetra silicate made by melt flux and by solid state synthesis.

Here are the exfoliated products. These images of the prepared materials show their textures and the differences in intensity of their blue color due to varying crystal sizes. The length scale on the first image holds for all these scanning electron microscopy images of gold coated bulk calcium copper tetra silicate show how the different preparation procedures lead to different crystalite sizes.

On the left, the product of the melt flux synthesis has five to 50 micrometer crystalite. The product of the solid state synthesis on the right has one to 15 micrometer crystalite powder. X-ray diffraction provides insight into the composition of the products.

Here are the patterns for the calcium copper tetra silicate series. The blue patterns correspond to the bulk material prepared by the melt flux root on the bottom and the subsequent exfoliated sample on top. The green patterns correspond to the bulk material prepared by the solid state root on the bottom and the subsequent exfoliated sample on top.

The asterisk indicate a silicon impurity. These representative transmission electron microscopy images show calcium copper tetra silicate nano sheets in the top two panels and barium copper tetra silicate nano sheets. In the bottom two panels.

The images on the left correspond to nano sheets derived from bulk materials prepared by melt flux roots, whereas the images on the right correspond to nano sheets derived from bulk materials prepared by solid state roots. Here is a rudimentary painting with the calcium copper tetra silicate nano sheet ink that illustrates both its simple application and its luminescence properties Following this procedure. Other techniques like spin coating, spray coating, inkjet printing, and layer by layer deposition can be used to process alkali earth copper, tetra silicate nano sheets for further study and applications development.