Features of Fabrication of Titanium Dioxide Based Coatings for Non-Lithographic Template Electrochemical Synthesis of Micron Metal Particle Arrays

This work is devoted to the development of non-lithographic template methods of synthesis. These methods have a significant advantage in terms of structure formation: there is no need to design and produce masks, which greatly simplifies the process, and more of them can work with nonplanar substrates. The purpose of this study was to reveal the conditions for the synthesis of titanium dioxide xerogel films of different topologies as well as to develop a technique for non-lithographic template electrochemical synthesis of micron metal particles arrays and to study the structure of the resulting coatings. The films were deposited on the surface of substrates via dip coating. Specific topology of the films was achieved by template sol-gel synthesis. Their structures were analyzed by SEM and XRD. Template synthesis of metal micro particles were realized by pulsed electrochemical deposition of metals into the perforations of xerogel films. Obtained materials were analyzed by SEM and XRD; the element distribution on the surface was determined by the EDS detector of SEM. Based on the analysis results, we suggest the mechanisms of formation of the xerogel topology and proved the efficiency of pulsed electrodeposition for template synthesis of micron particles arrays.

Sol–gel deposited xerogel, aerogel and porogen based porous low-k thin films: A comparative investigation

Low dielectric constant (Low-[Formula: see text]) films are used as inter layer dielectric (ILD) in nanoelectronic devices to reduce interconnect delay, crosstalk noise and power consumption. Tailoring capability of porous low-[Formula: see text] films attracted more attention. Present work investigates comparative study of xerogel, aerogel and porogen based porous low-[Formula: see text] films. Deposition of SiO2 and incorporation of less polar bonds in film matrix is confirmed using Fourier Transform Infra-Red Spectroscopy (FTIR). Refractive indices (RI) of xerogel, aerogel and porogen based low-[Formula: see text] films observed to be as low as 1.25, 1.19 and 1.14, respectively. Higher porosity percentage of 69.46% is observed for porogen-based films while for shrinked xerogel films, it is lowered to 45.47%. Porous structure of low-[Formula: see text] films has been validated by using Field Emission Scanning Electron Microscopy (FE-SEM). The pore diameters of porogen based annealed samples were in the range of 3.53–25.50 nm. The dielectric constant ([Formula: see text]) obtained from RI for xerogel, aerogel and porogen based films are 2.58, 2.20 and 1.88, respectively.

Montecarlo Simulation and HAXPES Analysis of Organosilane Segregation in Titania Xerogel Films; Towards a Generic Surface Chemofunctionalization Process

The formation of xerogels implies a sequence of hydrolysis and condensation reactions, which are intricate to analyze in heteromolecular sols. We analyze by probabilistic Montecarlo methods the development of hybrid organosilane–titania xerogels and illustrate how partial charges of the reacting molecules can help estimating relative probabilities for the condensation of the molecules. Since the condensation rate of Ti alkoxides is much higher than the corresponding rate of Si alkoxides (especially if bearing a non-hydrolizable group), by imposing a fast condensation process in agreement with low pH kinetics, the process leads to a surface segregation of the organosilane. The simulation results are compared with results of characterization of thin condensates of two different organosilanes within a titanium–isopropoxide matrix. Non-destructive in-depth profiles were obtained by hard x-ray photoelectron spectroscopy, which can resolve through estimation of Si and specific moieties of the organosilane molecules the progress of the condensation. These results are relevant for the generalization of chemo-functionalization processes by kinetic demixing of organosilanes, which have myriad applications in biomedicine and biotechnology.

Use of Natural Biopolymers to Create Nanocomposite Materials

Method of carbon nanotubes disaggregation with the help of protein material, gelatin, has been proposed which facilitate to disperse evenly nanotubes in hydrogels based on gelatin and polysaccharides (sodium alginate or κ-carrageenan). In the obtained composite hydrogels carbon nanotubes are located in the biopolymer matrix, i.e. being in biocompatible form without losing their unique properties. The removal of water from the pores of the hydrogel by means of freeze drying allowed to obtain materials having high porosity and with included carbon nanotubes. The produced hydrogels can be used to create eco-friendly composite materials for biomedical and technical purposes. Depending on the tasks the developed systems can also be used in the forms of xerogel (films), cryogel, aerogel, and even in the form of powder, containing carbon nanotubes.