LAUSR

Abstract Polyelectrolyte multilayers have received broad interests in the fields of functional coatings due to their easy deposition procedure, environmentally friendly nature and wide sensitivities to manifold external stimuli. Stimuli-triggered generation of nanoscopic structures on polyelectrolyte multilayers can be reversible generally when their structural size is less than dozens of nanometers. Transforming larger structures reversibly would represent a breakthrough of these materials for novel applications. Herein, we report that surface structures up to hundreds of nanometers can be developed on exponentially growing polyelectrolyte multilayers reversibly, which feature the diffusion of polyelectrolytes throughout the whole assemblies. These multilayers are prepared utilizing pH-amplified layer-by-layer assembly of branched polyethylenimine and photo-reactive poly(acrylic acid) azido derivative. Other than applying a single stimulus on the mobility of polymeric chains, the surface structures were developed by inducing electrostatic repulsion between chains in aqueous phases while subsequently erased by shielding supramolecular electrostatic interactions in gaseous phases. These processes are completely reversible and one potential application of this dynamic platform is to be a “smart” material for reversible visualization of various high-definition patterns with fine brightness contrast, which can be especially significant in some cutting-edge fields like the Internet of Things, information encryption/decryption and anti-counterfeiting. Beyond that, such dynamic platform can be very useful in many other research fields, such as surface wettability and smart homes.