Amine-terminated nanoparticle films: pattern deposition by a simple nanostencilling technique and stability studies under X-ray irradiation.

Thin films made up of arrays of amine-terminated silicon nanoparticles (NH2-SiNPs) synthesized by a new evaporation technique have been formed by employing TEM grids as nanostencils. FTIR imaging illustrates the feasibility of the method in nanoscale device fabrication applications. Micro-mapping over areas of the nanoparticle material allows the surface chemistry to be examined. FTIR imaging shows trace amounts of oxide confined to the NP surfaces. Thicker films formed by dropcasting allowed the nanoparticle behaviour to be studied under conditions of extended exposure to 150 eV photons radiation by X-ray photoelectron spectroscopy (XPS). The XPS spectrum was monitored over the Si2p region and the initial peak at 100.53 eV was observed to shift to higher binding energies as irradiation progressed which is indicative of charge trapping within the film. This result has potential consequences for applications where NH2-SiNPs are used in X-ray environments such as in bioimaging where the increasing charge buildup is related to enhanced cytotoxicity.

Chemical functionalization of nanodiamond by amino groups: an X-ray photoelectron spectroscopy study.

The development of chemical functionalization techniques for diamond nanocrystallites opens up ways with a view to altering their solubility in different solvents, improve interfacial adhesion of nanodiamonds with a composite matrix in new materials, and provide new possibilities for the modification of the electronic properties of nanodiamond crystallites. In this work, we present results on the chemical functionalization of nanodiamonds by amino groups using ammonia as a nitrogenation agent. Nanodiamond material used was formed by the detonation technique with average crystallite sizes of 4-5 nm. The final materials and intermediates products were characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Chemical functionalization of nanodiamonds by amino groups could enable the preparation of new nylon nano-composite materials. Presence of surface amino groups could alter pH of nanodiamond colloids towards basic values and improve colloidal stability of nanodiamond suspensions at pH close to 7. This could enable syntheses of new drug delivery systems based on nanodiamonds.