ИСТИНА

Nanoporous materials (NPM) and composites based on them have occupied a wide niche in modern science and technological applications such as refining, cleaning, catalysis, storage, biological and chemical sensing. Together with natural NPM such as zeolites and animal or vegetable fibers, there are a number of technologies allowing the creation of NPM with different architectures, a wide range of porosity, internal surface area, shape and size of pores, and degree of their interconnection. Transparent NPM such as zeolites, glass, aerogels, and polymers offer attractive opportunities in optics. In the area of applied science, NPM are useful in developing optical devices such as biological, or chemical sensors. Introduction of fluids or nanoparticles into the pores opens up the perspectives of creating artificial composite systems with outstanding properties defined by the type and the concentration of admixtures. Transparent NPM allow to use optical and nonlinear optical probing of processes and phenomena taking place under the nanoporous confinement. A large surface area of NPM is extremely convenient to study the interaction between the molecules of fluid and the solid walls, while the geometrical restrictions are suitable to investigate physico-chemical properties of a fluid under nanometric confinement. The modification of nanopores by introducing the nanoparticles opens up further perspectives of creating composite systems for catalysis, sensing, etc. Coherent anti-Stokes Raman scattering (CARS) has proved its efficiency for diagnostics of fluid phase behavior in nanopores with diameter of several nanometers including near-critical temperatures. The interference nature of CARS provides simultaneous probing of both the fluid and the porous host and, therefore, allows to characterize both the fluid phase composition and the host porous structure. In the present work, CARS spectroscopy is applied to comparatively analyze the vibrational spectra of carbon dioxide in pores of nanoporous glass (NPG) with and without silver nanoparticles inside. Three dimensional NPG samples with cylindrical pores of radius of about 2 nm are used. Nanoparticles are created via the impregnation of the NPG samples with the silver-containing precursor and the following thermo-chemical processing. The high spatial resolution scheme is used to probe the area deep inside a three dimensional nanoporous host.