1. Could you explain the significance of your article to the non-specialist? 

An important sub-class of inorganic-organic hybrid materials comprises organic polymers with a reinforcing inorganic component. The conceptually simplest types are polymers reinforced by inorganic filler particles. This approach has been extended to reinforcement by nanosized inorganic components making use of their high surface area per filler volume that generates a high proportion of interphone. The most recent approach for particle-reinforced polymers is based on molecular clusters, which constitute structurally well-defined nanosized building blocks. Strong chemical bonds between the clusters and the polymer matrix are necessary to ensure a homogeneous and stable dispersion in the polymer. To this end, clusters with functional organic groups are required that allow their use of co-monomers in polymerization reactions. The function of the clusters in the cluster-reinforced polymers is that of an inorganic cross linker, combined with that of a (nano)filler. This provides interesting new properties to the materials.

2. What has motivated you to conduct this work? 

Having previously prepared a variety of transition metal oxide clusters with polymerizable organic ligands for free-radical polymerizations, we felt that clusters compatible with other polymerization techniques need to be developed to fully exploit the possibilities of the approach. In this work, we have demonstrated that transition-metal clusters suitable for ring-opening metathesis polymerizations (ROMP) can be synthesized and successfully employed as co-monomers.

3. Where do you see this work developing in the future? 

The deliberate positioning of molecular building blocks and their mutual arrangement is one of the big issues for further improving the properties of inorganic-organic hybrid materials. The pre-arrangement of the molecular building blocks to larger entities, as it is the case for clusters of defined size and shape and capped by deliberately chosen organic functionalities, may be a step towards this goal.

4. Are there any particular challenges facing future research in this area? 

The interesting properties of hybrid polymers prepared by the cluster approach are determined by the combination of crosslinker and filler effects. A third dimension in properties could be implemented, if clusters with intrinsic physical properties could be used, such as optical or magnetic properties.