High-Performance Nanofibers and Nanostructures for New Generation Multifunctional Materials

The recent interest in nanotechnology has triggered research on nanofibers and nanostructures. Here we present our work on fiber-based multifunctional materials including nanofibers obtained via electrospinning processes. Such nanofibers are of potential value given the highly porous structures they form and their large surface area-to-volume ratio which is often required in high performance applications. We investigated cellulose-based microstructures that may offer unique opportunities due to its high stiffness and strength as well as the possibility of subsequent surface chemical modification. Our research involved first the isolation of cellulose whiskers from filter paper followed by the incorporation of the whiskers in hydrophobic polymer (polystyrene) matrices. The overall aim is to tailor the functionalities and properties of the resulting composites. Cellulose filler and polymer matrices were casted as composite films. These films together with electrospun webs were characterized using scanning electron microscopy (SEM). The preliminary results show that the nanofibers produced had average diameters of 250 300 nm. Also, there is a significant effect on the cellulose whiskers concentration on the storage modulus of the composite (MPs). As the concentration of cellulose whiskers is increased a significant increase on the storage modulus is observed, compared with a control film (no cellulose whiskers added). We used surfactants to increase the stability of the dispersion. However, it was found that there is an optimum surfactant concentration to obtain films with the highest strength.