Dr Tom Hasell

Porous materials are permeable, high surface area materials with applications in gas storage, catalysis, and filtration. There has been considerable interest in porous materials over the last ten years, and metal-organic frameworks and porous polymers with incredible properties have been reported. However, many of these new materials are limited in application due to the high cost of production. We are developing new porous materials from inorganic waste and other low cost or renewable resources. The target is to produce materials with superior properties, but at a cost that makes them useful for widespread practical applications, especially filtration of toxic pollutants from water and air flows. A good example is sulphur-polymers. Sulfur is an industrial by-product of oil refining. We recently showed that when polymers made from elemental sulfur are made porous, they can be used to filter mercury from water.
- Porous inverse vulcanised polymers for mercury capture

Much of Tom's research in Liverpool has been on the synthesis and characterisation of porous organic cages and their applications. Cages are a relatively new area of porous materials. Unlike extended frameworks, they are discrete, soluble molecules. The porosity is prefabricated and intrinsic to the molecular cage structures - which contain an internal void and open window to allow guest access.
Key papers:
- Cages for SF6 separation
- Directing the crystallisation of cages - controlling polymorphs
- Three component cage cocrystals - Porous organic alloys
- Cage nanocrystals
- Catenated cages - Triply interlocked molecules

Supercritical CO2, (scCO2) is a "green" solvent. It is produced when CO2 is heated above its critical temperature (32 degrees C) and compressed over its critical pressure (7.4 MPa). It then has liquid and gas like properties - like a gas it occupied the entire volume of the vessel, with no meniscus or surface tension, but like a liquid the molecules are close enough together to act as a solvent. It has tune-able density, high diffusivity, is non-combustible and non-toxic as well as being relatively environmentally benign, and as it is a gas at ambient temperatures and pressures it can be easily removed after reaction, leaving no solvent residues. It can be used in the processing and impregnation of organic polymers with inorganic components to form hybrid materials. Key papers:
- Silver Nanoparticle Impregnated Polycarbonate Substrates for Surface Enhanced Raman Spectroscopy
- Silver nanoparticle–polymer composites by supercritical CO2 polymerisation
- Palladium Nanoparticle Incorporation in CMPs
- Metal-polymer nanocomposites by supercritical fluid processing (book chapter)