Constellation color changing mug _ How to use the constellation color changing mug

Have you ever seen a cup that changes color? After pouring hot water, interesting patterns or cute photos will appear on the cup. Isn't it amazing? Do you want to know the chemical principle behind this?

People are usually used to calling ceramic cups with handles mugs. There is a kind of ceramic cup, its appearance is black, red, green or other colors, but when hot water is poured into the cup, the original color of the cup will gradually fade from bottom to top, and special patterns will appear. After a few minutes, the pattern became clear. If the water in the cup is cold, the pattern on the cup will gradually disappear, revealing the original color of the cup. What the hell is going on here?

It turns out that this color-changing mug has a layer of temperature-sensitive coating made of heat-sensitive material than ordinary cups. Thermosensitive materials, also known as thermochromic materials, will change from colored to colorless, or from colorless to colored, and can also change from one color to another according to the change of temperature. Common thermochromic materials are composed of an electron donor (developer), an electron acceptor (developer) and a solvent. The color developer receives the electrons provided by the color developer and produces a color reaction, while the solvent determines the color change temperature of the material. The chromogenic agent includes triarylmethane phenol and fluorane compound. Chromogenic agents are mainly phenolic hydroxyl compounds and their derivatives, and solvents are mostly alcohols (such as n-hexadecanol). When the temperature rises, the electrons in the atom are transferred, which leads to the change of the molecular structure of organic matter, thus realizing the change of color. This reaction is reversible. When the temperature returns to the original temperature, the molecular structure of the material also returns to the original state, and the color will also return to the original color.

Color-changing mugs are very convenient to make. The thermochromic material is ground into powder particles of 3 ~ 10 micron, and then mixed into water-based coatings, which are first coated on ordinary ceramic cups, then put into an oven, and baked at a high temperature of about 320℃ to remove moisture and binder, so that the thermochromic material is solidified on the ceramic cups. Then input the photos or photos to be "printed" on the cup into the computer, and then print them on a piece of thermal transfer paper with a special "printer". Thermal transfer can print patterns on various materials. The specific manufacturing method is to print the pattern on a special transfer paper with special transfer ink, then stick it on the thermochromic coating on the outer surface of the cup, put it in an oven, and perform thermal transfer at about 220℃. A few minutes later, transfer paper's photo was printed on the cup, and a special color-changing mug was made. When hot water is added to the cup, the thermochromic coating becomes colorless and transparent, and a delicate coating appears.

Temperature-sensitive substances were originally extracted from plants. In order to obtain more kinds of colors and higher yield, scientists have artificially synthesized a large number of temperature-sensitive materials. Different temperature-sensitive materials have different sensitive ranges to temperature, so the color of color-changing cups made of different materials changes with temperature.