Minhao Wong

Large-scale self-assembled zirconium phosphate smectic layers via a simple spray-coating process

The large-scale assembly of asymmetric colloidal particles is used in creating high-performance fibres. A similar concept is extended to the manufacturing of thin films of self-assembled two-dimensional crystal-type materials with enhanced and tunable properties. Here we present a spray-coating method to manufacture thin, flexible and transparent epoxy films containing zirconium phosphate nanoplatelets self-assembled into a lamellar arrangement aligned parallel to the substrate. The self-assembled mesophase of zirconium phosphate nanoplatelets is stabilized by epoxy pre-polymer and exhibits rheology favourable towards large-scale manufacturing. The thermally cured film forms a mechanically robust coating and shows excellent gas barrier properties at both low- and high humidity levels as a result of the highly aligned and overlapping arrangement of nanoplatelets. This work shows that the large-scale ordering of high aspect ratio nanoplatelets is easier to achieve than previously thought and may have implications in the technological applications for similar materials.

Glass transition temperature changes of melt-blended polymer nanocomposites containing finely dispersed ZnO quantum dots

We report the linear increase in the glass transition temperature, Tg, with nanofiller weight content. ZnO quantum dots dispersed by melt-blending in a poly(methyl methacrylate) host were characterized by differential scanning calorimetry and dynamic mechanical analysis showing that the Tg of the system is described by a power law of the interparticle distance, hp, where the percolation exponent, ν, was 0.55 to 0.64. Our analysis demonstrates that the characteristic length of the polymer in PNCs is in the range of 0.41–0.90 nm. Our results suggest that polymer nanocomposites can be described by the quantitative models of polymer thin films.