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1
Content available remote Optical properties of nanoporous glass filled with TiO2 nanostructures
Viter R., Geveluk S., Smyntyna V., Doycho I., Rysiakiewicz-Pasek E., Buk J., Kordas K.
Optica Applicata
|
2012
|
Vol. 42, nr 2
307-313
EN
Titanium dioxide nanoparticles (NP) and nanofibers (NF) were incorporated from polymeric gels into porous glasses. Two types of glasses A and B with different porosity were chosen for measurements. Optical absorbance and photoluminescence spectra of the samples were measured at the range of 200-1100 nm and 370-800 nm correspondently before and after TiO2 incorporation. The enhancement of TiO2 photoluminescence (PL) and short-wave shift of peaks for samples A and B was found. The obtained results are explained by quantum confinement effects.
2
Content available remote Microwave-assisted phase separation of alkali-borosilicates in the production of nanoporous glasses
Kullmann J., Enke D., Hahn T., Bauerschaefer U., Ledig L., Gai S., Bochmann A.
Optica Applicata
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2012
|
Vol. 42, nr 2
255-263
EN
The influence of a hybrid thermal processing on the spinodal decomposition of sodium borosilicate glasses was investigated. The pore diameter of the resulting porous glasses is a function of the parameters of the thermal treatment. One result of this study was the inversion of the phase separation under preservation of the external shape of glass monoliths. Furthermore by using microwaves in addition to thermal radiation it was possible to generate temperature gradients in the samples and so gradients in pore size too. The glass templates were heated with microwaves in a tube furnace consisting of a resonant rectangular waveguide (TE103). Additionally the tube wall was heated by thermal radiation. The heating control was realized by steering the input power and the frequency of a 200 W semiconductor source. The regulation was performed with a HOMER 3-stub tuner, which simultaneously measured the impedance by reflected wave analysis and the actual template temperature with an IR-sensor. Various temperature-time courses of the hybrid furnace led to different pore size gradients. This was discussed by analyzing specific properties like mean pore diameter, surface area and pore volume. Further effects like the pore orientation and properties of the pore walls were determined by scanning electron microscopy and focused ion beam (FIB).
3
Content available remote Characterization of pore filling of mesoporous host systems by means of positronium annihilation lifetime spectroscopy (PALS)
Kullmann J., Enke D., Thraenert S., Krause-Rehberg R., Beiner M.
Optica Applicata
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2012
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Vol. 42, nr 2
281-286
EN
Positronium annihilation lifetime spectroscopy (PALS) is an alternative method for the determination of pore sizes and pore size distributions. It is a measuring methodology which shows no limitations in the lower nanometer region and works, besides, without destruction of the sample material. It can be used for the characterization of open and closed pores. Additionally, this technology offers the possibility to obtain pore filling ratios of gases, liquids and solids precisely. Polymorphous medicaments, like acetaminophen, show different crystallization behavior within a pore system, depending on the pore size. This property can be used to control the crystalline state of the medicament and to optimize therefore the pharmaceutical use of the active substance. In this study, acetaminophen (C8H9NO2), also known as Paracetamol, is incorporated into different porous systems. The filling of the pores is realized by an acetaminophen melt at 453 K. The silica membranes are dipped into the melt, subsequently removed and cooled. Information concerning the filling ratio of the pores with the pharmaceutical was received with the help of PALS. The extended Tao-Eldrup model forms the theoretical base, taking into account the pore size sensitive annihilation properties of the ortho-positronium in matter.
4
Content available remote Photoluminescence features of AgBr nanoparticles formed in porous glass matrices
Doycho I. K., Gevelyuk S. A., Ptashchenko O. O., Rysiakiewicz-Pasek E., Tolmachova T. M., Tyurin O. V., Zhukov S. O.
Optica Applicata
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2010
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Vol. 40, nr 2
323--332
EN
The photoluminescence of AgBr nanoparticles formed by a two stage liquid-gas microsynthesis technology in two types of porous glass with different sizes of pores was investigated. Polyvinyl alcohol (Polinol) was used as a binder. It has been found that AgBr nanoparticles in the glasses with smaller pores luminesce more intensively, and we attribute this phenomenon to the differ-ences in pore size distributions. The luminescence spectra were shown to have two maxima corresponding to AgBr nanoparticles formed within the nanopores of two different sizes characteristic of each of the matrices. In both cases, the spectra excited by xenon lamp irradiation are more intensive than those stimulated by a 337-nm nitrogen laser. Comparing the maxima shifts in the phosphorescence excitation spectra with ones in phosphorescence spectra we can conclude that the luminescence and phosphorescence centers in AgBr nanoparticles are of identical nature in the matrices of both types. The investigation results fit neatly into the inherently consistent quantum confinement model and are well correlated with the poroscopic spectra of both types of glass.
5
Content available remote Electrical conductivity of doped porous glasses as possible sensors for oxygen
Saraidarov T., Reisfeld R., Elena Zigansky E., Sashchiuk A., Lifshitz E.
Optica Applicata
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2008
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Vol. 38, nr 1
109-117
EN
We are proposing Rubpy complex incorporated in a number of porous sol-gel thin films as a sensor for oxygen. The principle is based on the following fact: triplet oxygen reacts with the excited states of Rubpy resulting in decay of luminescence of the complex due to triplet quenching. The decrease of fluorescence is proportional to the amount of absorbed oxygen. We discuss here several sol-gel matrices with doped by Ru(bpy)3+2 deposited as thin films on ITO conducting glass. The absorption and emission spectra of the complex, and electrical conductivity of the doped films show how the fluorescence can be excited either by optical or electronic means. The decrease of fluorescence indicates the concentration of oxygen.
6
Content available remote Dynamical heterogeneity of NaNO2 confined within porous glasses
Dvornikov V., Korotkov L., Naberezhnov A., Fokin A., Korotkova T.
Optica Applicata
|
2008
|
Vol. 38, nr 1
25-29
EN
Frequency dependences of imaginary part of the dielectric response e(f) of SiO2-NaNO2 nanocomposite, prepared by embedding of sodium nitrite into porous glasses with 7 nm average pore diameter, have been studied within a temperature range of 360-520 K. It has been found that the spectrum S(omega) = e(f)/f contains the component ~1/f alfa where alfa is a coefficient indicating the dynamical heterogeneity of dipoles. Peculiarities of the temperature dependence of alfa are discussed.
7
Content available remote Application of porous glasses in microfluidic devices
Evstrapov A.A., Esikova N.A., Rudnitskaja G.E., Antropova T.T.
Optica Applicata
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2008
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Vol. 38, nr 1
31-38
EN
Nowadays a perspective appears of applying porous glasses in microanalytical devices. The opportunity of application of porous glasses as optical sensors has been shown in the present paper. Preliminary results of studying the electroosmotic flows through porous glasses are discussed.
8
Content available Porowate szkła modyfikowane Al2O3 w ochronie środowiska wodnego
Rogowska-Kwas R., Macuda J., Procyk B.
Wiertnictwo, Nafta, Gaz
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2005
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R. 22/1
261--266
PL
Poddawany badaniom laboratoryjny materiał, jakim są szkła porowate z układu Na2O-B2O3-SiO2, do likwidacji zanieczyszczeń węglowodorowych ze środowiska wodnego, posiada w zależności od składu chemicznego i od temperatury, w której prowadzony był proces likwacji, różną powierzchnię sorpcyjną. Badania tekstury szkieł porowatych wykazały różnice w wielkości i objętości, zarówno mezo- jak i mikroporów. Własności te mają wpływ na skuteczność usuwania substancji węglowodorowych z roztworów wodnych. W artykule przedstawiono wyniki badań laboratoryjnych oczyszczania wody z zanieczyszczeń pochodzenia benzynowego przy wykorzystaniu szkieł porowatych. Dla pokazania wpływu wielkości i objętości porów na własności sorpcyjne badania prowadzono przy użyciu dwóch szkieł - modyfikowanych 0,3 Al2O3 i 0,6 Al2O3, dla których proces likwacji prowadzony był w temperaturach 575 lub 700 stopni Celsjusza.
EN
Porous glasses representing the Na2O-B2O3-SiO2 group were analysed with the emphasis on hydrocarbon contaminations removal from water environment. Depending on their chemical composition and temperature at which the removal process was carried out, the glasses varied in their surface of sorption. The results of tests on the texture of porous glasses exhibited differences in the size and volume of meso- and micropores. These properties may have an ultimate influence on the efficiency of hydrocarbons removal from water solutions. The paper gives the results of laboratory analyses of gasoline-removal from water with the use of porous glasses. To show the influence of the size and volume of pores on sorption properties, analyses were made on two porous glasses modified with 0.3 Al2O3 and 0.6 Al2O3, for which the removal process was performed at 575 or 700 Celsius degrees.
9
Content available remote Spectroscopic and dielectric characteristics of nickel-doped porous silica glasses
Macalik B., Suszyńska M., Rysiakiewicz-Pasek E., Krawczyk L., Morawska-Kowal T., Okal J.
Optica Applicata
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2005
|
Vol. 35, nr 4
761-767
EN
The direct current conduction and electrical relaxation currents in nickel-doped porous silica glasses were investigated by using the thermally stimulated polarisation and depolarisation current techniques in a wide temperature range. Optical absorption measurements and transmission electron microscopy observations accompanied these studies. All characteristics were found to be affected by the porous matrix and the material filling the pores.
10
Content available remote Porosity of sol-gel silica glasses doped by ruthenium bipyridyl as measured by positron annihilation lifetime spectroscopy and nitrogen adsorption
Reisfeld R., Zigansky E., Jasińska B., Wodnicka K.
Optica Applicata
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2005
|
Vol. 35, nr 4
677-689
EN
The porous structure of glasses incorporated by ruthenium tris bipyridyl chloride (further Rubpy) and adsorbed by Rubpy is studied by positron annihilation lifetime spectroscopy and liquid nitrogen adsorption method. The first method provides the radius of the pores in the range of 0.6-4 nm and their distribution. The second method provides the radius of the pores in the range of 1-150 nm, their total volumes, size distribution and specific surface area. In the first method both closed and opened pores can be seen when the measurements are made on bulk samples as in this work. When thin films are measured, one has to use a capping material to prevent backscattering. The dimension of the pores can be controlled by the catalyst used for sol-gel formation. When Rubpy is prepared by adding its salt to precursor solution catalyzed by HCl, the pore size increases because of stress exhibited by large molecules. The pore size decreases with adding of Rubpy in precursor solution, catalyzed by HF and HNO3. Glass doped by Rubpy is less sensitive to the type of catalyst, than undoped glasses. A comparative study was performed on undoped glasses prepared by the identical method. We shall discuss the similarities and differences of the two methods.
11
Content available remote Effect of structure parameters and composition of high-silica porous glasses on their thermal and radiation resistant properties
Antropova T.V., Volkova A.V., Petrov D.V., Stolyar S.V., Ermakova L.E., Sidorova M.P., Yakovlev E.B., Drozdova I.A.
Optica Applicata
|
2005
|
Vol. 35, nr 4
717-723
EN
The influence of a composition of initial phase-separated alkali borosilicate glass and its thermal treatment as well leaching conditions on the parameters of the porous glass structure are discussed. The results obtained by adsorption and conductivity methods, transmission electron microscopy and dilatometer technique were used to analyse the effect of structure parameters and composition of high-silica porous glasses on their thermal and radiation resistant properties.
12
Content available remote Application of electron microscopy methods to the study of porous and quartz-like glasses
Drozdova I.A., Antropova T.V., Tolkachev M.D.
Optica Applicata
|
2005
|
Vol. 35, nr 4
709-715
EN
The structure of high-silica porous glasses and quartz-like (Vycor type) glasses has been investigated by transmission and scanning electron microscopy and by electron micro-probe analysis. Porous glasses (PGs) have been manufactured by acid leaching of phase-separated alkali borosilicate glass plates. To obtain the quartz-like glasses the PG samples were sintered at different temperatures up to 900°C. Before sintering a part of PGs was impregnated with salt solutions containing Ag. Features of the structure of quartz-like glass matrix are revealed. The parameters and arrangement of a photosensitive Ag-Hal phase in photochromic quartz-like glasses are determined.
13
Humidity dependencies of porous sol-gel and silica glass linear sizes
Geveluyk S. A., Doycho I. K., Prokopovich L. P., Rysiakiewicz-Pasek E., Safronsky E. D.
Materials Science
|
2002
|
Vol. 20, No. 2
23-27
EN
Measurements of the porous sol-gel and porous silica glass linear size dependencies on humidity of the surrounding atmosphere were performed using the interferometric techniques. The secondary silica gel existing in the voids of silica porous glasses is absent in the sol-gel glasses. The pore size distributions have two peaks for the sol-gel glass while there are several peaks with decreasing amplitudes in the silica porous glass. The differences in the linear sizes moisture sensitivity are explained by the structure of both types of porous materials. The capillary effects prevail in the last ones. The revealed peculiarities of sol-gel glasses make it possible to develop threshold humidity sensors of the new type.
14
Content available remote Szkła porowate.
Procyk B.
Szkło i Ceramika
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2001
|
R. 52, nr 5
9-14
PL
Przedmiotem pracy są szkła porowate z układu Na2O-B2O3-SiO2 modyfikowane MoO3 oraz podwyższoną zawartością B2O3 (do 50% mol.). Otrzymane szkła charakteryzują się powierzchnią właściwą od 20 do 420 m kwadratowych/g i średnią średnicą porów od 2,0 do 15 nm, w zależności od składu chemicznego szkła oraz parametrów obróbki termicznej i chemicznej. W szkłach tych obserwuje się znaczną liczbę mikroporów, o średnicy poniżej 1,7 nm. Przeprowadzono badania strukturalne tych szkieł.
15
Content available remote Porous glasses as a host for solid state tunable lasers in the visible as a means for fluorescence diagnostics and photodynamic therapy.
Reisfeld R, Yariv E.
Optica Applicata
|
2000
|
Vol. 30, nr 4
481-490
EN
Lasers prepared by incorporation of the active dyes into porous glasses are described. The background of the use of lasers for photodynamic therapy and diagnostics is outlined. The role of hematoporphyrin and hypericin in creation of singlet oxygen which destroys the malignant tissues, is explained. The lasers, based on sol-gel technology, incorporated by several perylimide and pyrromethane dyes emit in the suitable range in which the hematoporphyrin is excited. These compact lasers may replace, in the future, the vapour and the liquid lasers. The synthesis and the spectroscopic properties of the laser are described.
16
Content available remote Linear extension of porous glasses with modified internal surface in humid environment.
Gevelyuk S. A., Doycho I. K., Lishchuk D. E., Prokopovich L. P., Safronsky E. D., Rysiakiewicz-Pasek E., Roizin Y. O.
Optica Applicata
|
2000
|
Vol. 30, nr 4
605-611
EN
An original interferometric technique for investigating the influence of humidity on change in the linear dimensions of porous silica glasses is developed. The linear dimensions of a specimen are shown to change as a result of competition in the system of compressive capillary forces and expansion forces arising from the swelling of the residual silica gel present in pores. The possibility of selective inhibition of the capillary squeezing forces or the silica gel expansion forces by the pre-treatment of a porous material by a hydrophobized composition (hexamethyldisilazan - HMDS) or by annealing of carbon impregnated inside of the pores is shown experimentally.
17
Content available remote Influence of water adsorption on mechanical properties of porous glasses.
Rysiakiewicz-Pasek E.
Optica Applicata
|
2000
|
Vol. 30, nr 1
173-176
EN
An influence of different treatment of porous glass (water adsorption, heat or hexamethyldisilazane treatment) on the values of elasticity parameters was investigated. The laboratory ultrasonic tests were used to determine the dynamical elastic modulus. The observed changes of the dynamic elastic modulus of porous glasses were related with processes of adsorption and desorption of water from the pores.
18
Content available remote High temperature treatment of porous glasses.
Marczuk K., Pater K.
Optica Applicata
|
2000
|
Vol. 30, nr 4
619-625
EN
The influence of thermal treatment on linear sizes and the internal structure of porous glasses has been investigated. A simple connection between porosity and shrinkage has been confirmed to exist except in microporous glasses with silica gel inside the pores, where in the initial stage of annealing the porosity was increasing when the glass shrank. A sponge structure of fracture mirrors of the walls of a carcass for glasses heated at about 650 degrees C is observed.
19
Content available remote Carbon treatment as a method of the surface development of porous glasses
Gevelyuk S.A., Doycho I.K., Kovalenko M.P., Safronsky E.D., Rysiakiewicz-Pasek E., Roizin Y.O.
Optica Applicata
|
2000
|
Vol. 30, nr 4
635-640
EN
A method to develop the structure of the internal pore surface is proposed. The surface of porous silicate glasses is modified by impregnating carbon into the pores and subsequent annealing. The procedure is repeated several times. A technique to control the properties of the pore surface is proposed as well. Analysing the change in the features of the photoluminescence spectrum as a result of such treatment in comparison with the pore-size distribution spectra allows us to assume formation of silicon nanoclusters in porous glass and to estimate their sizes. The nonmonotonic change of the surface development with simultaneous stationary increase of photoluminescence intensity is explained by the composite pattern of the silicon clusters change during multiple carbon treatments.
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