Cellulose Nanocrystals Examined by Atomic Force Microscopy: Applications and Fundamentals

Cellulose nanocrystals (CNCs) are nanoscale particles with huge surface areas, excellent mechanical properties, and the ability to develop tunable surface chemistry, thus allowing them to be mixed into a wide range of matrices. Using atomic force microscopy (AFM), we highlight recent developments in the microstructural characterization of CNC particles in various shapes at both particle and organization scales. Considering new uses for CNC suspensions and gels and given the considerable potential of CNC-based products in medicinal, energy, cosmetics, filtration, and food applications, leveraging existing state-of-the-art characterization technologies such as AFM to improve CNC-produced properties cannot be ruled out. AFM may be used as a probe to disclose more intimate information about CNCs and can show modulus, size, and morphology in comparison to other characterization tools. AFM based on the literature review here was found to be a good assessment tool to verify the state of interaction, the adhesion strength of certain particles or chemicals, and the mechanical properties of CNCs. Thus, in tandem with other technologically advanced characterization tools, knowledge provided here for proper assessment of CNCs is necessary. Based on the AFM application currently widespread on CNCs, it appears that more research efforts are needed to provide additional cues regarding CNC individual states or the organized state (isotropic or liquid crystalline) for future sustainable, ecofriendly product designs based on CNCs.