**Preface to "Nanocellulose and Nanocarbons Based Hybrid Materials: Synthesis, Characterization and Applications"**

Since the emergence of nanotechnology in recent decades, the development and design of hybrid bio-nanomaterials has become an important field of research. Looking at the growing concern about the environment and sustainability, such nanomaterials find many applications in a wide range of domains that influence our society and our way of life. The improvement in properties and the discovery of new functionalities are key goals that cannot be reached without a well controlled and better understanding of the preparation, characterization, and manufacturing of new hybrid nanomaterials, which constitute the starting points of the design of specific and adequate systems. The investigation of nanocellulose/nanocarbons hybrid materials has demonstrated both academic and technological importance and offered great research opportunities within cross-disciplinary areas. Nanocellulose, which refers to the cellulose with a nanoscale dimension, encompasses cellulose nanocrystals, cellulose nanofibrils, and bacterial cellulose. It displays outstanding features such as biocompatibility, eco-friendliness, renewability, interesting reinforcing potential, hydrogen-bonding capacity, low thermal expansion coefficient, dimensional stability, high elastic modulus, high specific surface area, and low density. Various nanocellulose-based composites, which found application in different fields, have been developed during the last two decades. However, numerous challenges need to be addressed to achieve the full requirement of advanced materials. Accordingly, several research activities continue to be performed by different research groups worldwide to develop the next generation of nanomaterials and fully explore the potential of nanocellulose. Nanocarbon is another exciting type of potential nanomaterials, which has received tremendous attention since the discovery of fullerenes over thirty years ago. They include carbon nanotubes, graphene and carbon dots. They exhibit outstanding thermal, electrical, optical and mechanical features, and they can be employed in a wide range of applications such as composites, microelectronics, biomedical, conductive films, sensors, adsorbents, catalysis, energy storage, and coatings, among others. Based on these premises, the present book aims to further contribute to the momentum of research and development in nanocellulose/nanocarbon hybrids, by featuring several different chapters authored and reviewed by experts in the field. This book targets a broad readership of materials scientists, chemists, physicists, and nanotechnologists, among others. Most of the chapters highlight theoretical concepts and practical approaches of interest for real-world applications related to nanocellulose and nanocarbons.

In summary, this book advances not only our understanding of the emerging and significant role of nanocellulose and nanocarbons in several fields, but also of the challenges and future research directions needed to fully explore their outstanding features in practical ways. It is also expected that this book will encourage multidisciplinary research activities on hybrid bio-nanomaterials, extending the range of potential practical applications taking into account the scaling-up of the systems, the economic viability, the impact on the environment and human health as well as the long-term stability and recyclability.

> **Djalal Trache, Vijay Kumar Thakur** *Editors*
