A Simply Synthesized Shaking-induced Small Molecule System with Repeatable and Instantaneous Discoloration Response.

Force-related discoloration materials are highly valuable because of their characteristics of visualization, easy operation, and environment friendliness. Most force-related discoloration materials focus on polymers and depend on bond scission, which leads to insensitivity and unrecoverable. Small-molecule systems based on well-defined molecular structures and simple composition with high sensitivity would exhibit considerable mechanochromic potential. However, to date, researches about force-related discoloration materials based on small molecule solution remain limited and are rarely reported. In this study, we developed a repeatable and instantaneous discoloration small molecule solution system by simple one-pot synthesis method. It exhibited an instantaneous chromic change from yellowish to dark green under shaking and reverting back to yellow within 1 minute after removal of the shaking. Experimental results confirmed that the discoloration mechanism is attributed to the oscillation accelerating the production of unstable ortho-OH phenoxyl radical. The newly developed shaking-induced discoloration small molecule system (SDSMS) promises in field of mechanical force sensing and optical encryption.