Controlling molecular assembly on time scale: Time-dependent multicolor fluorescence for information encryption

Abstract

Dynamic assembly on time scale is common in biological systems but rare for artificial materials, especially for smart luminescent materials. Programming molecular assembly in a spatio-temporal manner and resulting in white-light-including multicolor fluorescence with time-dynamic features remains challenging. Herein, controlling molecular assembly on time scale is achieved by integrating a pH-responsive motif to a transient alkaline solution which is fabricated by activators (NaOH) and deactivators (esters), leading to automatic assembly on time scale and time-dependent multicolor fluorescence changing from blue to white and yellow. The kinetics of the assembly process is dependent on the ester hydrolysis process, which can be controlled by varying ester concentrations, temperature, initial pH, stirring rate and ester structures. This dynamic fluorescent system can be further developed for intelligent fluorescent materials such as fluorescent ink, three-dimension (3D) codes and even four-dimension (4D) codes, exhibiting a promising potential for information encryption.