Fluorescence Lifetime Imaging of Alkyl Ammonium Modified Self-Assembled Helicoidal Cellulose Nano Crystal Films: How Reactivity Controls Polymer Dynamics

Due to the large volume fraction of nanoscale-reinforcement in cellulose-rich CNC-polymer nanocomposites and the extensive surface area, nearly all the soft/polymeric phase is interfacial (interphase polymer) and therefore, under nanoconfinement. It is well-established that the dynamic properties of any interphase polymer are determined by the structure of the polymer and strength of the interactions with the hard phase, and can deviate significantly from that of the neat polymer. With optimal interfacial interactions, this leads to significantly enhanced performance in many natural composites, such as those found in crustacean and insects shells, and bone. Yet, the role of interfacial interactions, polymer structure, and nano-confinement in helicoidal cellulose nano crystal nanocomposites remains incompletely understood. Here, we use fluorescently labelled helicoidal cellulose nanocomposites and fluorescent lifetime imaging microscopy (FLIM) to study the nature of the effect of polymer structure (cross linked, blend) on the confinement effect in alkyl ammonium modified sulfate-CNC. nanocomposites. Figure 1