All-Cellulosic-Based Biomimetic Composite Systems

Composite materials are heterogeneous systems composed of at least by two different phases, commonly designated as matrix and reinforcement. These designations are associated with the distinct properties (mechanical, thermal or electric) of the two phases. The reinforcement can be of micro- (microcomposites) or nanosize (nanocomposites). The field of nanocomposites is a rapidly expanding area of research generating new materials with unique properties. Several new materials have been developed within the last decade incorporating nanosized filler materials in polymer matrices. 

The use of nanomaterials has proven to confer various advantages as already mentioned above, namely improved mechanical, thermal and barrier properties compared to nonfilled polymers. These effects are largely due to their high interfacial area, their aspect ratio, and their extent of dispersion and percolation, which occur when the filler particles are present in quantities above the threshold where they start interacting [23,24]. 

Alternative routes, due to environmental awareness and increasing interest in sustainable material concepts, have led to the development of bio- and green composites for structural composite applications, the so-called all-polymer composites or self-reinforced polymer composites . These new materials promise to overcome the critical problem of fiber-matrix adhesion in biocomposites by using chemically similar or identical cellulose materials for both matrix and reinforcement and are designated as all-cellulose composites [39, 40]. 

In this section we will focus on All-Cellulose biomimetic materials based on liquid crystalline phases of cellulose derivatives. 

One of the most interesting phenomena of the liquid crystalline polymers (LCPs) that cannot be expected in flexible or small-molecule liquid crystals is the band texture. 

---