Résumé
•Modeling of active substance releases through and from cellulose nanofiber coating.•Investigation of one mathematical solution of the Fick’s second law of diffusion.•Comparison of two different substances: Caffeine vs chlorhexidine digluconate (CHX).•Model validation with caffeine: Predominantly diffusion-controlled release proved.•Predictive simulation of the behavior of the developed active paper-based packaging.
Cellulose nanofibers (CNFs) were recently investigated for the elaboration of new functional food-packaging materials. Their nanoporous network was especially of interest for controlling the release of active species. Qualitative release studies were conducted, but quantification of the diffusion phenomenon observed when the active species are released from and through CNF coating has not yet been studied. Therefore, this work aims to model CNF-coated paper substrates as controlled release system for food-packaging using release data obtained for two model molecules, namely caffeine and chlorhexidine digluconate. The applied mathematical model – derived from Fickian diffusion – was validated for caffeine only. When the active species chemically interacts with the release device, another model is required as a non-predominantly diffusion-controlled release was observed. From caffeine modeling data, a theoretical active food-packaging material was designed. The use of CNFs as barrier coating was proved to be the ideal material configuration that best meets specifications.