Research progress of water responsive compound material in the field of green writing and anti-counterfeiting

Water stimulus responsive materials can undergo reversible color or fluorescence emission change process under the external stimulus of water. Because of its low cost, non-toxic, compatibility with existing inkjet printing technology and other advantages, it is an ideal choice to achieve rewritable. Meanwhile, it shows great application potential in information storage, security and anti-counterfeiting. In this review, the research progress of water responsive compound material based on organic small molecules in the past five years is systematically reviewed. Inductive materials are classified from the viewpoints of water induced proton transfer, water induced configuration change, water induced proton transfer combined with configuration change sensing principle. The achievements and technologies in design principles, optical physical properties and information storage applications are summarized. It is hoped to provide ideas for further developing the application of water responsive composites in the field of green writing and anti-counterfeiting, promoting the development of related industries.