Recent advances in cellulose nanospheres: production, formation mechanisms, properties and applications

The morphology of cellulose nanomaterials plays a crucial role in determining their properties and expanding their application possibilities. Among these bionanomaterials, cellulose nanospheres (CNSs) have emerged as a novel form, distinguished by unique spherical morphology and properties that depend on their size, crystallinity, and surface chemistry. These properties make CNSs suitable for various applications, ranging from additives in nanocomposites to biomedical uses. Despite its promising potential, CNSs are underreported in the literature, highlighting the need for a comprehensive evaluation of production, mechanism, and performance perspectives. This review provides an in-depth examination of the primary methods used for CNS production, including acidic, enzymatic, mechanical, and oxidative processes. We analyze the complex relationship between these production methods, the resulting spherical characteristics, and the yields obtained during isolation. Additionally, we examine the various proposed mechanisms for CNS formation and advance these mechanisms, which are essential for optimizing and tailoring production processes to achieve specific structure outcomes. Finally, we discuss recent advancements in CNS applications across different sectors and address future research directions and challenges for this innovative bionanomaterial.