Design, fabrication, and application of dynamic, stimuli-responsive soft surfaces

The surface chemistry and microstructure of a material determine its macroscopic (e.g., wettability, adhesion) and microscopic (e.g., catalytic activity, molecular speciation) interfacial properties. Synthetic strategies applicable to the design and fabrication of well-defined interfaces, including prototypical systems based on self-assembled monolayers, polymer coatings, and microtextured materials, have been reported extensively by the surface science community. These systems are typically supported on mechanically rigid/planar supports, providing stable surfaces ideally suited for applications demanding static and predictable interfacial properties. Emergent technologies, including soft actuators and robotics, stretchable sensors and electronics, and surface fluidics, demand mechanically compliant, elastic support substrates and dynamically adaptive chemical/mechanical surface properties that are inaccessible in traditional systems. Accordingly, there have been considerable efforts to design, synthesize, and characterize new varieties of soft, stimuli-responsive surfaces. This article provides an overview of state-of-the-art stimuli-responsive soft surfaces, emphasizing those with mechanical and chemical control vectors. Specifically, the synthetic strategies, dynamic properties for adaptive response, prospective applications, existing challenges, and future opportunities for these new stimuli-responsive surfaces are covered.