Cellulose Nanomaterials: Nanocomposite Imaging using FRET
Jeffrey W. Gilman, Mauro Zammarano, Iulia A. Sacui, Jeremiah Woodcock
Cellulose is the most abundant organic polymer on Earth, found in plants (cotton, hemp, wood), marine animals (Tunicate), algae (Valonia) bacteria (Acetobacter xylium) and even amoeba (Dictyostelium discoideum). Critical features of the structural performance of cellulose in these diverse settings are the large aspect ratio and high strength properties of the cellulose nanocrystals (CNC) and cellulose nanofibers (CNF), which provides nano-scale reinforcement. The isolation of CNC originated with Mukherjee's research in1953.1 Acid hydrolysis of the native cellulose is the predominant method used to prepare pure CNC and CNF. Depending on the source of the cellulose and the chemical treatment the resulting material can vary in crystalline type, surface chemistry, dimensions, and aspect ratio. This class of materials is gaining increased importance due to their novel properties (high strength, low thermal expansion, rich surface chemistry and optical transparency). Primary drivers for their use include their renewability and proven low toxicity. Consequently, several pilot plants and a number of commercial scale CNC manufacturing facilities have recently gone online worldwide utilizing wood as the raw material. The applications envisioned range from transportation to biomedical. However, recently the use of CNCs in nanocomposites has become the focus of international research efforts.2 The development of measurement methods, which can characterize the structure and morphology of cellulose nanocomposites over many length scales, are needed to enable successful manufacturing and product development of cellulose nanomaterials.3 A project at NIST is developing fluorescence imaging methods to measure interface properties in cellulose nanocomposites.
Production and Applications of Cellulose Nanoparticles