The emergence of hybrid cellulose nanomaterials as promising biomaterials

Cellulose nanomaterials (CNs) are promising green materials due to their unique properties as well as their environmental benefits. Among these materials, cellulose nanofibrils (CNFs) and nanocrystals (CNCs) are the most extensively researched types of CNs. While they share some fundamental properties like low density, biodegradability, biocompatibility, and low toxicity, they also possess unique differentiating characteristics such as morphology, rheology, aspect ratio, crystallinity, mechanical and optical properties. Therefore, numerous comparative studies have been conducted, and recently, various studies have reported the synergetic advantages resulting from combining CNF and CNC. In this review, we initiate by addressing the terminology used to describe combinations of these and other types of CNs, proposing "hybrid cellulose nanomaterials" (HCNs) as the standardized classifictation for these materials. Subsequently, we briefly cover aspects of properties-driven applications and the performance of CNs, from both an individual and comparative perspective. Next, we comprehensively examine the potential of HCN-based materials, highlighting their performance for various applications. In conclusion, HCNs have demonstraded remarkable success in diverse areas, such as food packaging, electronic devices, 3D printing, biomedical and other fields, resulting in materials with superior performance when compared to neat CNF or CNC. Therefore, HCNs exhibit great potential for the development of environmentally friendly materials with enhanced properties.