Study of lithium encapsulation in porous membrane using ion and neutron beams

Ion track-etched membranes are porous systems obtained by etching of the latent ion tracks using a suitable etchant solution. In this work, control of the pores' spatial profiles and dimensions in PET polymers was achieved by varying etching temperature and etching time. For determination of the pores' shape, Ion Transmission Spectroscopy technique was employed. In this method, alterations of the energy loss spectra of the transmitted ions reflect alterations in the material density of the porous foils, as well as alterations of their thickness. Simulation code, developed by the team, allowed the tomographic study of the ion track 3D geometry and its evolution during chemical etching. From the doping of porous membranes with lithium-based solution and its analysis by Thermal Neutron Depth Profiling method, the ability of porous PET membranes to encapsulate nano-sized material was also inspected. The study is important for various applications, e.g., for catalysis, active agents, biosensors, etc

Laser-generated nanoparticles to change physical properties of solids, liquids and gases

Synthesis of nanoparticles was possible employing a Nd: YAG pulsed laser at fundamental harmonic. The production of nanoparticles in water depends mainly on the laser parameters (pulse duration, energy, wavelength), the irradiation conditions (focal spot, repetition rate, irradiation time) and the medium where the ablation occurs (solid target, water, solution concentration). The nanoparticles can be introduced in solids, liquids or gases to change many physical characteristics. The optical properties of polymers and solutions, the wetting ability of liquids, the electron density of laser-generated plasma, represent some examples that can be controlled by the concentration of metallic nanoparticles (Au, Ag, Ti, Cu). Some bio-medical applications will be presented and discussed

Ion track etching in polyethylene-terephthalate studied by charge particle transmission technique

In the paper, thin films of polyethylene-terephthalate, pristine or irradiated with 170 MeV Xe+ ions to the fluence of 105 cm−2, were etched in the mild 1 M NaOH medium at 60°C for different times. The main aspects of the etching process (i.e. development of the pores, dependence of the foil thickness and transparency on the time of etching) were studied by the ion transmission technique (ion energy loss spectroscopy) that was previously introduced by the author’s team. It has been shown that the transmission method makes it possible to closely monitor the development of the polymeric porosity and to determine the important parameters of the etching process (e.g. etching rate along the latent tracks, bulk etching rate, radial etching rate, breakthrough, foil transparency). The measurement was carried out at the NPI Rez using the alpha particle microprobe on the Tandetron accelerator

Measurement of Li diffusion in porous carbon by neutron depth profiling

Diffusion of Li in porous carbon material has been studied using a nondestructive neutron depth profiling technique. It has been acknowledged that carbon-based materials are good candidates for electrodes in lithium-ion batteries. It is because they exhibit a high ability to effectively release Li ions during charging and discharging processes. The Li diffusion was studied in porous carbon material with several annealing cycles. The produced data were useful for the determination of relative straight porosity level and diffusion coefficient, which result to be between 5.13E-11 cm2/s and 5.56E-11 cm2/s, that agree with the literature but obtained with a technique that does not alter the sample during the analysis