Selluloosan nanokiteiden ja biopohjaisten pinta-aktiivisten aineiden välisen itsejärjestäytymisen pohjalta valmistettujen uusien materiaalien suunnittelu

The increasing global production of plastics underscores the urgent need for sustainable alternatives to fossil-based plastics. Due to their renewability, biodegradability, strong mechanical properties, and specific water interactions cellulose nanocrystals (CNCs) have attracted considerable attention as bio-based nanomaterials. However, challenges related to their dispersion, stability, and gelation limit their direct use in advanced material applications. This dissertation explores the potential of combining CNCs with sugar-based biosurfactants prepared by microbial fermentation to design fully bio-based and sustainable material systems. The overarching aim was to investigate how biosurfactants can enhance the dispersion and functionality of CNCs while maintaining simplicity and renewability in the resulting materials. Three objectives guided the work: (i) elucidating the dispersion of uncharged CNCs using biosurfactants, (ii) developing multicomponent hydrogels combining CNCs and biosurfactants, and (iii) evaluating the role of biosurfactants in CNC gelation. These objectives have been met through three publications. The results demonstrate that biosurfactants can effectively stabilize CNC dispersions, significantly enhance the mechanical and responsive properties of CNC-based hydrogels and reduce the gelation threshold of negatively charged CNCs. Taken together, this dissertation provides the first systematic evidence that biosurfactants can act as versatile, fully bio-based agents to overcome key limitations of CNCs. Building on this groundwork, future research should focus on examining biosurfactant–cellulose interactions at the molecular level, optimizing preparation conditions, and translating these insights into application-driven designs. These findings establish a foundation for the rational design of sustainable CNC–biosurfactant systems, paving the way toward impactful real-world applications.