Self‐Assembled Silver–Gold Nanoisland Films on Glass for SERS Applications

We present a study of resonant optical properties of gold‐protected silver nanoisland films. Silver nanoislands were grown on a glass substrate using out‐diffusion technique, the growth was followed by the deposition of nanometer‐thick gold coatings. Scanning electron microscopy and optical spectroscopy were used to characterize morphology and extinction spectra of the grown combined silver–gold nanostructures. Micro Raman spectroscopy of the combined nanoislands has demonstrated their signal enhancement factor exceeding that one of the initial silver nanoislands.     

Use of the time-of-flight mass spectrometer to study the volatile products from mechanical degradation of polymers in a vibration grinder

Problems about the use of the mass-spectrometry method to study the compositions and kinetics of evolution of volatile products formed during the process of mechanical degradation of polymers in a vibration grinder are examined. A vibration ball mill was directly connected to the vacuum chamber of a time-of-flight mass analyzer. By use of this method, mass spectra of the volatile products evolved during vibration grinding of samples of polymethyl methacrylate, polytetrafluoroethylene, polyethylene, and poly-α-methylstyrene have been obtained. The possibility of studying the kinetics of evolution of volatile products as a function of the amplitude and duration of grinding has been shown in the case of polymethyl methacrylate and of polytetrafluoroethylene.     

Features of the Crystal Structure of the Polyimide Derived from 3,3'-Diaminobenzophenone and 3,3',4,4'-Benzophenonetetracarboxylic Dianhydride

Changes occurring in the structural organization of the thermoplastic polyimide derived from 3,3'-diaminobenzophenone and 3,3',4,4'-benzophenonetetracarboxylic dianhydride on heat treatment at temperatures in the range 250-350°C were studied, and the influence of these changes on the rheological behavior of the polymer was examined.     

Self-assembled silver nanoparticles in glass microstructured by poling for SERS application

A simple technique to fabricate microchannels in glasses with self-assembled silver nanoparticles (NPs) in the channels is presented. It combines thermal-electric poling of silver-to-sodium ion-exchanged glass slides with a patterned anodic electrode, formation of the microchannels via selective etching off the unpoled slide regions, and hydrogen annealing. The annealing results in the growth of NPs only on the bottom of the channels. The studies performed allowed optimizing the channels’ depth and NPs surface density for Surface Enhanced Raman Scattering (SERS) based sensing and microfluidic applications. We have demonstrated that the formed NPs allow detection of 1/20 of BPE (1,2-Di(4-pyridyl)ethylene 97%) monolayer, the evaluated Raman enhancement factor being ~4·10⁷. The proposed approach based on the glass poling allowed us the fabrication of ~1 μm deep channels and easy multiplication of the structures because the anodic electrodes used for the poling are capable of multiple usage.     

Studying Evolution of the Ensemble of Micropores in a SiC/Si Structure during Its Growth by the Method of Atom Substitution

Physics of the Solid State - The time evolution of the ensemble of micropores formed in the near-surface region of silicon during the growth of thin films of silicon carbide is studied by the...     

A New Trigonal (Rhombohedral) SiC Phase: Ab Initio Calculations,a Symmetry Analysis and the Raman Spectra

Physics of the Solid State - A new trigonal (rhombohedral) SiC phase, existence of which was previously theoretically predicted by a symmetry analysis, is studied. It is shown that the phase can be...