Bio-Based and Biodegradable Films and Coatings for a Circular Economy: Advanced Fabrication, Multiscale Characterization, and Emerging Applications

Dear Colleagues,

The environmental burden of fossil-derived plastic packaging and protective coatings has become one of the defining materials challenges of our time. Global plastic production continues to rise, yet only a small fraction of packaging waste is effectively recycled, with the remainder accumulating in landfills, waterways, and terrestrial ecosystems, where fragmentation into micro- and nanoplastics raises mounting ecological and human-health concerns. Tightening regulatory frameworks, including the EU Single-Use Plastics Directive, the Packaging and Packaging Waste Regulation, and comparable measures across Asia and the Americas, together with rising consumer demand for sustainable products, are accelerating the search for viable alternatives. Biodegradable films and coatings, formulated from polysaccharides (starch, cellulose, chitosan, alginate, and pectin); proteins (gelatin, zein, whey, soy, and other plant protein isolates); lipids and waxes; and microbial or bio-based polyesters (PLA, PHA, PBS, and PBSA), have emerged as one of the most promising routes to replacing persistent synthetic barriers across food, agricultural, biomedical, and industrial sectors.

Despite remarkable laboratory progress, the translation of these materials into commercial products remains constrained. Moisture sensitivity, brittleness and poor elongation, insufficient oxygen and water vapor barrier performance, weak substrate adhesion, thermal instability during melt processing, batch-to-batch variability arising from natural feedstock heterogeneity, and the absence of harmonized end-of-life testing protocols continue to limit industrial adoption. Cost competitiveness against commodity polyolefins remains a further barrier. At the same time, new opportunities are reshaping the field: the valorization of agro-industrial by-products and side streams, fruit and vegetable pomace, peels, oilseed meals, brewery spent grain, and crustacean shells into film-forming matrices and functional fillers; nanoreinforcement with nanocellulose, nanochitin, lignin nanoparticles, and bio-based nanofillers; the incorporation of essential oils, plant extracts, bacteriocins, and antioxidant compounds for active packaging; pH-responsive colorimetric indicators and sensor-integrated systems for intelligent freshness monitoring; multilayer, bilayer, and hybrid architectures that decouple mechanical and barrier functions; and greener deposition routes such as electrospinning and electrospraying, layer-by-layer assembly, cold plasma treatment, supercritical fluid processing, spray and dip coating, and extrusion or compression coating.

Realizing this potential depends on characterization that goes well beyond routine tensile and permeability testing. Understanding structure–property relationships in these systems requires multiscale interrogation of surface topography, wettability and surface free energy, crystallinity, molecular interactions within the polymer network, filler dispersion and interfacial adhesion, and the migration behavior of active compounds under realistic storage conditions. Equally important is rigorous, standardized assessment of end-of-life behavior, industrial versus home compostability, soil and marine biodegradation, ecotoxicity of degradation products, coupled with life-cycle assessment and techno-economic analysis that credibly benchmark these materials against the incumbents they aim to displace. Studies that connect formulation and processing decisions to measured performance and that report validated real-food or real-substrate trials rather than model systems alone are especially needed.

This Special Issue aims to present and disseminate the most recent advances in the design, fabrication, characterization, and application of biodegradable films and coatings. We invite original research articles, comprehensive reviews, and short communications addressing novel biopolymer formulations, surface and interface engineering, functional performance evaluation, biodegradation behavior, and demonstrated end-use applications across food, agricultural, biomedical, and technical sectors.

Topics of interest for publication include, but are not limited to, the following:

• Novel biopolymer matrices, blends, composites, and compatibilization strategies for biodegradable films and coatings;
• Valorization of agro-industrial by-products, food waste, and biorefinery side streams as film-forming feedstocks;
• Advanced fabrication and deposition techniques: solvent casting, extrusion and blown film, electrospinning and electrospraying, layer-by-layer assembly, spray/dip coating, and 3D printing;
• Nanoreinforcement strategies using nanocellulose, nanochitin, nanoclays, lignin nanoparticles, and other bio-based nanofillers;
• Plasticization, cross-linking, and compatibilization approaches to improve flexibility and mechanical integrity;
• Active coatings incorporating antimicrobial, antioxidant, and bioactive compounds, including essential oils and plant extracts;
• Intelligent and smart films: freshness and spoilage indicators, pH-responsive colorimetric systems, time–temperature indicators, and sensor integration;
• Surface modification, hydrophobization, wettability, adhesion, and interfacial characterization;
• Barrier performance: water vapor, oxygen, carbon dioxide, aroma, UV–visible light, and grease resistance;
• Multilayer, bilayer, and hybrid coating architectures for decoupled functionality;
• Encapsulation, emulsion-based systems, and controlled or triggered release of functional agents;
• Biodegradation, compostability, ecotoxicity, migration, food-contact safety, and life-cycle assessment;
• Antimicrobial and biofunctional coatings for biomedical devices, wound dressings, and implant surfaces;
• Biodegradable coatings in agriculture: seed coatings, controlled-release fertilizers, and mulch films;
• Scale-up, pilot-scale processing, industrial feasibility, regulatory considerations, and techno-economic analysis.

Contributions that combine mechanistic insight with application-oriented validation and that report reproducible, standardized protocols are particularly encouraged. We look forward to receiving your contributions and to assembling a collection that helps move biodegradable films and coatings from promising laboratory results toward practical, scalable implementation.

Dr. Matias Menossi
Guest Editor

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