Biodegradable and water-soluble polymers in block copolymer architectures

Polymers that are both biodegradable and water-soluble present a compelling alternative to traditional, environmentally persistent materials. While a significant body of research exists on biodegradable hydrophobic polymers in block copolymers (BCPs), the study of their biodegradable, water-soluble counterparts remains less explored. In contrast to previous reviews focusing on hydrophobic components, this review provides a comprehensive overview of recent developments in the field of biodegradable water-soluble polymers (WSPs), highlighting their versatility as building blocks for BCPs. We discuss various classes of WSPs, including polyphosphoesters, poly(amino acids), and modified polyesters, and examine their degradation mechanisms, which can be either hydrolytic or enzymatic. By synthesizing recent advances across multiple polymer classes, this work underscores their contribution to the development of fully degradable, functional nanostructures. We emphasize how integrating these WSPs into BCPs, often with conventional biodegradable hydrophobic blocks, enables the creation of fully degradable nanostructures. These materials can self-assemble into various morphologies, such as micelles and polymersomes, with potential applications in drug delivery and environmental remediation. The article also provides a critical perspective on their environmental fate, emphasizing the importance of understanding their degradation profiles for a sustainable end-of-life.