Surface immobilized polyamidoamine (PAMAM) dendrimer templated Pt nanoparticles were employed as precursors to heterogeneous catalysts. CO oxidation catalysis and in situ infrared spectroscopy were used to evaluate conditions for dendrimer removal. Infrared spectroscopy showed that PAMAM dendrimer amide bonds begin decomposing at temperatures as low as 75°C. Although the amide stretches are completely removed after 3 h of oxidation at 300°C, 16 h were required to reach maximum catalytic activity. Further treatment under oxidizing or reducing atmospheres did not cause substantial changes in activity. Infrared spectroscopy of the activated materials indicated that organic residues, probably surface carboxylates, are formed during oxidation. These surface species passivate the Pt NPs, and their removal was required to fully activate the catalyst. Substantially less forcing activation conditions were possible by employing a CO/O2/He oxidation treatment. At appropriate temperatures, CO acts as a protecting group for the Pt surface, helping to prevent fouling of the nanoparticle by organic residues. CO oxidation catalysis and infrared spectroscopy of adsorbed CO indicated that the low temperature activation treatment yielded supported nanoparticles that were substantially similar to those prepared with more forcing conditions.

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Multiferroic composites are promising candidates for magnetic field sensors, next-generation low power memory and spintronic devices, as they exhibit much higher magnetoelectric (ME) coupling and coupled ordering parameters compared to the single-phase multiferroics. Hence, the 3-0 type particulate multiferroic composites having general formula (1 − Φ)[PbFe0.5Nb0.5O3]-Φ[Co0.6Zn0.4Fe1.7Mn0.3O4] (Φ = 0.0, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 1.0, (1 − Φ) PFN-ΦCZFMO) were prepared using a hybrid synthesis technique. Preliminary structural and microstructural analysis were carried out using XRD and FESEM techniques, which suggest the formation of 3-0 type particulate composite without the presence of any impurity phases. The multiferroic behaviour of the composites is studied with polarization versus electric field (P-E) and magnetization versus magnetic field (M-H) characteristics at room temperature. The nature of ME coupling was investigated elaborately by employing the Landau free energy equation along with the magneto-capacitance measurement. This investigation suggests the existence of biquadratic nature of ME coupling (P2M2). The magneto-electric coupling measurement also suggests that strain mediated domain coupling between the ferroelectric and magnetic ordering is responsible for the magneto-electric behaviour. The obtained value of direct ME coefficient 26.78 mV/cm-Oe for Φ = 0.3, found to be higher than the well-known single-phase materials and polycrystalline composites.

In the present work, zirconium (Zr) modified strontium bismuth titanate (SBT) ceramics were prepared by soild state reaction route and its effects on the structural and electrical properties were thoroughly investigated.

Bacterial attachment and biofilm formation on implant surface has been a major concern in hospital and industrial environment. Prevention of bacterial infections of implant surface through surface treatment could be a potential solution and hence this has become a key area of research. In the present study, the antibacterial and biocompatible properties of femtosecond laser surface treated 45S5 bioactive glass (BG) have been investigated. Adhesion and sustainability of both gram positive S. aureus and gram negative P.aeruginosa and E. coli nosocomial bacteria on untreated and laser treated BG samples has been explored. An imprint method has been used to visualize the growth of bacteria on the sample surface. We observed complete bacterial rejection potentially reducing risk of biofilm formation on laser treated surface. This was correlated with surface roughness, wettability and change in surface chemical composition of the samples before and after laser treatment. Biocompatibility of the laser treated BG was demonstrated by studying the anchoring and growth of human cervix cell line INT407. Our results demonstrate that, laser surface modification of BG enables enhanced bacterial rejection without affecting its biocompatibility towards growth of human cells on it. These results open a significantly potential approach towards use of laser in successfully imparting desirable characteristics to BG based bioimplants and devices.