Abstract

Dynamic covalent polymer networks are viscoelastic, self-healing materials that have applications in soft robotics, adhesives, 3D printing, and reusable plastics, including coatings. Using poly(dimethyl siloxane)-based dynamic polymer networks, we designed an ultra-thin polymer coating. The PDMS thin film is superhydrophobic, transparent, and adaptable to rough or curved surfaces, making it ideal for multiple applications from the energy sector for solar panels to the commercial sector for cars or as screen protectors. This gel network can be applied to various surfaces (glass, metals, silicon) at heights of 10 nm – 1 micron and still achieve self-healing from pinholes and cuts, prevent delamination of the coating, and promote dropwise condensation for multiple weeks. To unite the dynamic polymer mechanical behavior on the macroscale to the microscale, the relaxation time of the dynamic polymer measured via rheology is compared to the self-healing behavior of a cut in the dynamic thin film using ellipsometry and Atomic Force Microscopy (AFM) as thin film polymer rheology. For non-dynamic glassy thin polymer films, the width of the cut with time follows a power law. This and other models dictating relationships between cut width and self-healing success are investigated for our dynamic polymer network. Factors such as film thickness, cut length and shape, and crosslinking density of the polymer are also used to tune the relaxation response of the material.