New bags are able to change colors, scratched clothes can heal like skin, and scraped car paint will become new when it is exposed to water. These sci-fi movie like scenes are gradually becoming a reality.
Recently, Professor Feng Wei and his co-workers from Tianjin (TJU) University developed a new intelligent material. It is so “smart” that it is not only mechanochromic butalso shape-programmable and self-healable. Supported by the National Natural Science Foundation of China, this research was reported as the cover article of Angewandte Chemie of German, an international authoritative journal.
The “adaptive discoloring and camouflaging capacity” of many organisms in nature has always been a very important research direction for polymer material scientists. Imitating the intelligent discoloration camouflage mechanism of natural organisms and developing new bioinspired intelligent discoloration materials and technologies are significant for social production and life, national defense industry and so on. Besides, improvement of the service life of advanced polymer materials will benefit economically and socially because many of them such as rubber, plastics, coatings and fibers, as important industrial materials, are consumed tremendously due to wear every year.
Inspired by the intelligent color changing mechanism of the chameleon in nature, Professor Feng Wei’s team integrated dynamic covalent boronic ester bonds into the main-chain CLCE (cholesteric liquid crystal elastomer) polymer network. Taking advantage of the thermo-activated dynamic B-O bond exchange characters, the team realized the controllable programming of color and 3D shape of the film, whose shape and color can even be reversibly tuned as the temperature changes. Successfully, a new intelligent material, the “smart discoloring liquid crystal polymer film” was born. This new material is only 200 microns thick. It has robust mechanochromic,shape-programmable, and room temperature self-healable capability: it can change color when stretched; it can heal after being cut off as a few water is added to the fracture so as to boast a longer service life; in addition, its shape-programmable function means that it can be stretched into and remain any 2D or 3D shape, and will return to the original shape only when it is heated above the phase transition temperature.
According to Professor Feng Wei, this research provides a simple and universal method for emerging technologies such asbioinspired camouflage materials, adaptive optics and soft robotics and also shows great application potential in fields including clothing, packaging materials and so on.
By: Liu Yaqian
Editor: Qin Mian
