Conformal electrodeposition of ultrathin polymeric films with tunable properties from dual-functional monomers†

Functional thin films and interphases are omnipresent in modern technology and often determine the performance and life-time of devices. However, existing coating strategies are incompatible with emerging mesoscaled 3D architected and porous materials, and fail to uniformly apply functional thin films on their large and complex interior 3D surface. In this report, we introduce an approach for obtaining conformal polymeric thin films using custom-designed dual-functional monomers possessing both self-limiting electrodeposition capability and the functionality of interest in separate molecular motifs. We exemplify this approach with the monomer triethylene glycol-diphenol and demonstrate the full coating of a 3D mesoscaled battery electrode with an ultrathin lithium-ion permeable film. Our comprehensive study of the processing–structure–property relationships enables the tailorable control over the conformal thickness (7–80 nm), molecular permeability, and electronic properties. The modularity and tunability of this approach make it a promising candidate for functional polymer film deposition on arbitrary 3D structures.