Our research mainly focuses on miscibility and interactions in polymer blends. By changing the chemical structures of the polymers systematically, we are able to understand the correlation between miscibility and chemical structure. Our research has led to the discovery of over 300 pairs of miscible polymer blends, representing nearly one-sixth of all miscible polymer blends reported in the literature. We have also found a homopolymer/copolymer blend system showing an unusual "immiscibility window" phenomenon. We have recently turned our attention to polymers that are capable of interacting strongly with each other, leading to the formation of interpolymer complexes.

Since miscibility arises from specific interactions between polymers, it is essential to study the existence and nature of such interactions. Fourier-transform infrared spectroscopy and solid-state nuclear magnetic resonance spectroscopy are commonly used to study interpolymer interactions. Although X-ray photoelectron spectroscopy (XPS) has been extensively used to study multi-component polymer systems, it is rarely used to study specific interactions in various polymer blends and complexes. Our recent studies have shown that XPS is a useful technique to study various types of interpolymer interactions such as hydrogen-bonding, ionic, dipole-dipole, p -complexation and co-ordination interactions.

Our recent work in this area includes the synthesis and miscibility behavior of fullerene-containing polymers, interpolymer complexation between fullerene-end-capped poly(ethylene oxide) and poly(acrylic acid) or poly(methacrylic acid), and also the aggregation behavior of fullerene-end-capped poly(ethylene oxide) in solutions.

We used a supramolecular approach to prepare fullerene-based polymer composites. Fullerene is functionalized and allowed to interact with selected polymers. Unlike the other fullerene-containing polymers in which fullerene is chemically linked to the polymeric networks, here the fullerene is physically linked to the polymer chains.

For double-fullerene-end-capped polymers, the aggregation of fullerene moieties results in network-like materials with good mechanical properties. A combination of a double-fullerene-end-capped polymer and a linear polymer generates a pseudo-semi-interpenetrating polymer network with outstanding mechanical properties.

The development of polymer/carbon nanotube nanocomposites faces two main problems: ability to disperse the carbon nanotubes in polymer matrix and to achieve efficient load transfer between the nanotubes and the polymer matrix. Our research in this area aims to overcome these two problems to produce nanocomposites with superior mechanical properties.