Polyoxometalate (POM) based gels are synthesized by reacting POMs with an excess of caprolactam. These POM-entrapped caprolactam gels are thermoreversible and possess good mechanical strength. The gelation of POMs in caprolactam matrix brought the gel acidity similar to the physiological pH. The cytotoxicity studies on SCC 131 cell lines using these gels show 50% of cell death in the range of 2 to 6 mM concentration in 48 h. The supramolecular caprolactam matrix with active protons and the redox property of POMs are responsiblefor the cytotoxicity effect.

A polyelectrolyte complex (PEC) made up of poly(di-allyl di-methylammonium chloride) and poly(styrene sulphonate) polyelectrolytes has been synthesised and used for the immobilisation of phosphomolybdate (PMo), [PMo₁₂O₄₀]^3- nanoclusters. The material is characterised by FTIR, powder XRD, SEM, TEM and UV-Visible DRS spectroscopy. It was found that the PMo clusters are intact in the hybrid and are present as nanoaggregates within the layers of PEC. The amount of PMo present in the hybrid is estimated from thermal measurements and the optical band gap energy of the material is found to be in the semiconductor region. The presence of negatively charged PMo clusters helped in almost complete adsorption of cationic dyes, methylene blue and rhodamine B. The PMo/PEC hybrid has shown to follow Langmuir adsorption isotherm in case of both the dye molecules.