Biodegradable Polymer Coatings: Current State‐of‐the‐Art, Recent Advances, and Still Open Challenges

Polymer coatings represent both a key academic research topic and a viable and well-established industry market. Their characteristics are unique and allow for their application on different types of substrates (such as metal alloys, ceramic materials, polymers, paper, and paperboard), even for uses characterized by high durability. The latter property is perhaps the one behind their extensive diffusion since it guarantees performance over a wide range of time, often comparable with the lifetime of the coated substrate. However, the durability of a coating is not always a desired and sought-after feature: in fact, there are applications for which the possibility to remove the coating on demand from the coated substrate becomes an extremely important goal, even in the logic of the circular economy. In this context, academic research is trying to develop and implement biodegradable polymer coatings, i.e., thin layers of material that may start interacting with the environment in specific conditions, breaking down into simple substances that do not exhibit toxicity or hazard. This work aims to review the current state-of-the-art related to biodegradable polymer coatings, providing the reader with an overview of the progress made so far in this research field and some perspectives for the coming years.