In this context, the valorization of lignocellulosic biomass into high-performance, bio-sourced packaging materials has emerged as a promising pathway toward sustainable alternatives. Among these, paper and paperboard are being reengineered to replace conventional plastic-based packaging, particularly in applications such as flexible multilayers. However, the intrinsic limitations of these materials—especially in meeting the stringent mechanical and barrier properties required for many packaging functions—underscore the need for continued innovation and material development.
Cellulose nanomaterials (CNMs), nanoscale materials derived from lignocellulosic biomass, offer a transformative opportunity in this space. CNMs, including cellulose nanofibrils (CNFs) and cellulose nanocrystals (CNCs), have demonstrated exceptional potential in enhancing the performance of traditional pulp and paper products. Through tailored processing and structural control, CNMs have shown the capability to rival and, in certain applications, surpass the performance of petroleum-based packaging materials.
Despite this promise, the widespread adoption of CNMs in packaging remains limited by a key challenge: their inherent sensitivity to water and moisture. Although various strategies have been explored over recent decades to mitigate the low water and moisture barrier properties of cellulose-based materials, the fundamental mechanisms governing these properties remain poorly understood. In particular, the relationships between CNM processing methods, resulting film structures, and their water vapor barrier performance have yet to be fully elucidated, posing a critical barrier to material optimization and broader application.
Our research group has been actively working to address this challenge through a variety of approaches, shedding light on the trade-offs between mechanical strength and water vapor barrier properties in CNF-based films and composites. Through systematic investigation, we have shown that enhancing one property often comes at the expense of the other, highlighting the need for a balanced, application-specific design strategy.
In this invited lecture, I will present our latest findings and ongoing research into the structure–process–property relationships that govern water vapor permeability in CNF-based materials. Emphasis will be placed on the interplay between CNF morphology, film structure, surface versus bulk performance, and the influence of processing conditions.