The exploration of nanocellulose has been aided by rapid nanotechnology and material science breakthroughs, resulting in their emergence as desired biomaterials. Nanocellulose has been thoroughly studied in various disciplines, including renewable energy, electronics, environment, food production, biomedicine, healthcare, and so on. Cellulose nanocrystal (CNC) is a part of the organic crystallization of macromolecular compounds found in bacteria’s capsular polysaccharides and plant fibers. Owing to numerous reactive chemical groups on its surface, physical adsorption, surface grating, and chemical vapor deposition can all be used to increase its performance, which is the key reason for its wide range of applications. Cellulose nanocrystals (CNCs) have much potential as suitable matrices and advanced materials, and they have been utilized so far, both in terms of modifying and inventing uses for them. This work reviews CNC’s synthesis, properties and various industrial applications. This review has also discussed the widespread applications of CNC as sensor, acoustic insulator, and fire retardant material.

Cellulose nanofibers (CNFs) are part of organic crystallization macromolecular compounds that can be found in bacteria’s capsular polysaccharides and plant fibers. CNFs have a lot of potential as suitable matrices and advanced materials, and there have been a lot of studies done on them so far, both in terms of modifying them and inventing uses for them. In this paper, CNFs/reduced graphene oxide (GO) (rGO) nanocomposites were developed to create renewable, flexible, and cheap humidity sensors. The composite film’s performance as a humidity sensor was evaluated by analyzing the variations in capacitance at different humidity levels. The synthesized composite film underwent characterization using various analytical techniques, including scanning electron microscopy (SEM), UV (ultraviolet)/Vis (visible) spectrophotometry, Fourier transform infrared spectroscopy (FTIR), and thermomechanical analysis (TMA). The sensing mechanism is elucidated based on hydrophilic functional groups within the composite material. It has been observed that 3 wt% rGO/CNF composite is the best suited for humidity sensing among all other samples.