Regulatable Thermochromic Hydrogels via Hydrogen Bonds Driven by Potassium Tartrate Hemihydrate

The thermochromic materials have received widespread attention due to their ability to adjust color under the environmental stimuli. However, it is still a challenge in the sensitivity of transmittance on temperature. Here, a novel type of thermochromic hydrogel is proposed and demonstrated to improve the sensitivity of transmittance to temperature. At different temperatures, the size of the micelle could be changed, giving the thermochromic ability for the hydrogel. As the temperature gradually increases to the thermochromic transition temperature (TTT), the hydrogels undergo a transition from opaque to transparent (90%) at 550 nm visible radiation the same as the near-infrared region. The reverse process occurs when the temperature drops below TTT. Meanwhile, TTT could be adjusted over a range of temperature from 25 to 35 °C by changing the content of potassium tartrate hemihydrate. This hydrogel provides a new approach to obtain thermochromic materials and has wide potential application in temperature monitoring and optical control fields.