Vivek K. Singh

Engineering of the function of diamond-like carbon binding peptides through structural design.

The use of phage display to select material-specific peptides provides a general route towards modification and functionalization of surfaces and interfaces. However, a rational structural engineering of the peptides for optimal affinity is typically not feasible because of insufficient structure-function understanding. Here, we investigate the influence of multivalency of diamond-like carbon (DLC) binding peptides on binding characteristics. We show that facile linking of peptides together using different lengths of spacers and multivalency leads to a tuning of affinity and kinetics. Notably, increased length of spacers in divalent systems led to significantly increased affinities. Making multimers influenced also kinetic aspects of surface competition. Additionally, the multivalent peptides were applied as surface functionalization components for a colloidal form of DLC. The work suggests the use of a set of linking systems to screen parameters for functional optimization of selected material-specific peptides.

Pulsed Electric Current Sintered Cr2O3-rGO Composites

Chromium oxide is a promising material for applications where excellent corrosion resistance, high hardness, and high wear resistance are needed. However, its use is limited because of low fracture toughness. Improvement of fracture toughness of chromium oxide while maintaining its afore mentioned key properties is therefore of high interest. In this communication we study the possibility of increasing the toughness of pulsed electric current sintered (PECS) chromium oxide by the addition of graphene oxide (GO). The indentation fracture toughness was improved markedly with the addition of graphene oxide. Materials prepared by direct chemical homogenization had better fracture toughness. In composites with 10 vol.% GO piling of thin graphene oxide layers resulted in the formation of graphite layers between Cr2O3 and in carbide formation, which were observed to be the main reasons for the degradation of the mechanical properties. The distribution of graphene oxide was more homogeneous, when the GO amount was 0.1 vol.% and the formation of graphitic layers were avoided due to lesser amount of GO as well as ultrasonic treatment following the ball milling.

Effect of graphene oxide loading in GO/SiO2/Ag/AgCl photocatalyst

In the presented work, Ag/AgCl decorated silica nanoparticles were introduced over graphene oxide (GO) sheets to prepare GO/SiO2/Ag/AgCl nanocomposite powders for absorption and photocatalytic application. Nanocomposite powders were synthesised by sol-gel method and then characterised by various analytical techniques including X-ray diffraction (XRD), scanning electron microscopy and transmission electron microscopy. The amount of GO in nanocomposites was varied from 1 wt.% to 50 wt.% to investigate the role of graphene oxide on the absorption and photocatalytic properties of the nanocomposites. The photocatalytic activity of the GO/SiO2/Ag/AgCl nanocomposites was examined under UV light taking methylene blue (MB) as a model dye.