Dual-Responsive Ultrathin Polymersomes with Reversible Transitions on Acidochromism and Fluorochromism Performances for Multiple Information Encryption.

Endowing dual-responsive ultrathin polymersomes (UTPSs) with reversible stimuli-chromic and fluorochromic performances offers a prospective yet challenging strategy for achieving high-level information encryption and anticounterfeiting. Herein, starting from rational synthesis of visible light/pH-responsive integrated azobenzene monomer, side-chain-type amphiphilic alternating azocopolymers were elaborately crafted using a moderate epoxy-amino click-polycondensation. Followed by subsequent solution self-assembly, dual-responsive UTPSs with a diameter of ∼253 nm and a vesicular thickness of ∼2.1 nm were subtly produced based on the pendant hydrophobic conjugate stacking mechanism. The photoisomerization of azobenzene units and protonation of tertiary amines within UTPSs were accountable for the visible-light- or pH-triggered reversible shape and physicochemical transitions (i.e., color, size, diameter, vesicular thickness, zeta potential, fluorescent intensity) as well as repeatable acidochromism from yellow to pink and recyclable fluorochromism, respectively. Benefiting from these attractive traits, the proof-of-concept 2D quick response code was meticulously crafted using the stimuli-chromic UTPSs into patterning lithography, showcasing a multilevel decryption, favorable reversibility, and preferable recyclability for advanced information security. Our work provides innovative guidelines for the development of dual-responsive UTPSs with multiple stimuli-chromism merits for the potential of complex information encryption.