Surface and Interface Engineering for Nanocellulosic Advanced Materials

How do trees support their upright massive bodies? The support comes from the incredibly strong and stiff, and highly crystalline nanoscale fibrils of extended cellulose chains, called cellulose nanofibers. Cellulose nanofibers and their crystalline parts—cellulose nanocrystals, collectively nanocelluloses, are therefore the recent hot materials to incorporate in man‐made sustainable, environmentally sound, and mechanically strong materials. Nanocelluloses are generally obtained through a top‐down process, during or after which the original surface chemistry and interface interactions can be dramatically changed. Therefore, surface and interface engineering are extremely important when nanocellulosic materials with a bottom‐up process are fabricated. Herein, the main focus is on promising chemical modification and nonmodification approaches, aiming to prospect this hot topic from novel aspects, including nanocellulose‐, chemistry‐, and process‐oriented surface and interface engineering for advanced nanocellulosic materials. The reinforcement of nanocelluloses in some functional materials, such as structural materials, films, filaments, aerogels, and foams, is discussed, relating to tailored surface and/or interface engineering. Although some of the nanocellulosic products have already reached the industrial arena, it is hoped that more and more nanocellulose‐based products will become available in everyday life in the next few years. Nanocelluloses, the natural reinforcement for plants, are incredibly strong and stiff, and are therefore under great scrutiny for incorporation in sustainable, ecofriendly, and strong man‐made materials. Nanocelluloses enable dramatic tailoring of surface chemistry, interface interactions, and functionalities via chemical and/or physical surface and interface engineering that permit assembly of diverse nanocellulosic materials. Some of the promising progress in this area is reviewed.