Full-text resources of PSJD and other databases are now available in the new Library of Science.
Visit https://bibliotekanauki.pl
Preferences help
Polish version English version Language
enabled [disable] Abstract
Number of results

Results found: 5

Number of results on page
first rewind previous Page / 1 next fast forward last

Search results

help Sort By:

help Limit search:
first rewind previous Page / 1 next fast forward last
1
Content available remote

Free-Volume Evolution of 1-Propanol Confined in Variously Filled Regular Mesopores of SBA-15 Matrix

100%
Šauša O., Lukešová M., Švajdlenková H., Bartoš J.
Acta Physica Polonica A
|
2017
|
vol. 132
|
issue 5
1572-1574
EN
The free-volume of 1-propanol (1-PrOH) confined in a regular mesoporous SBA-15 matrix was investigated by desorption experiment at room temperature and over a wide temperature range, from 15 K up to 350 K, for four different contents of 1-PrOH in the pores. The gradual desorption of 1-PrOH from the mesopores as well as the free volume temperature dependences have shown that the polar molecules of 1-PrOH located at the inner polar surface of the SBA-15 matrix are more strongly bound to the matrix surface. The subsequent discussion of the annihilation and free-volume characteristics follows.
2
Content available remote

Does Positronium Feel Dynamics of Polymer Chain?

88%
Krištiak J., Šauša O., Bandžuch P., Zrubcová J., Bartoš J.
|
|
vol. 95
|
issue 4
596-604
EN
The annihilation experiments on simple elastomers at wide temperature interval of (15-370) K will be described. The results are consistently interpreted using free-volume models of polymer structure. The procedure of deducing some parameters of theory of polymers (e.g. viscosity, Vogel-Fulcher temperature) from the positron annihilation experiments will be shown. A great potential of positron annihilation in the study of amorphous polymers will be emphasized.
3
Content available remote

Thermal Expansion of Free-Volume in Hexadecane Confined in the Silica Gel Nanopores

88%
Šauša O., Majerník V., Illeková E., Macová E., Berek D.
|
|
vol. 125
|
issue 3
798-800
EN
Temperature dependence of the free-volume of voids in hexadecane (HXD) confined in the 3 nm silica gel pores (Develosil-30) was measured by positron annihilation lifetime spectroscopy. Different amount of HXD was filled into the pores of matrix. The anomalous thermal expansion was observed in the partially filled pores with extremely low filling. The thermal expansion coefficient of free-volume voids in this solidified HXD layer has a negative sign at temperatures below 180 K compared to high- or full-filled pores of silica gel. At these temperatures, the positron annihilation lifetime spectroscopy measurements demonstrate the appearance of a new type of the free volume within HXD which has been interpreted as the cracks in the HXD layer on the inner walls of matrix cavities. The differential scanning calorimetry method confirmed that the processes were enacted within pores and not on the outer surfaces of silica gel grains. In the sample with the extremely low filling, only the one HXD solidification/melting effect connected with confined states is manifested.
4
Content available remote

Nanopores in Silica Aerogels

76%
Šauša O., Iskrová M., Majerník V., Krištiak J., Jesenák K., Vargová M.
Acta Physica Polonica A
|
2008
|
vol. 113
|
issue 5
1517-1522
EN
The size of nanopores in thermally treated samples of silica aerogels was determined by ortho-positronium lifetime measurements at room temperature. The annealing of samples in the temperature region of 300-800°C does not make substantial changes in pore size felt by positronium. The annealing at higher temperatures from an interval of 800-1050°C causes shrinkage of the samples reducing the pore size to 1-15 nm. The macropores vanish at temperature treatment at 1000°C and the positron annihilation is not affected by oxygen from air.
5
Content available remote

Network Properties of Ureasil-Based Polymer Matrixes for Construction of Amperometric Biosensors as Probed by PALS and Swelling Experiments

52%
Kavetskyy T., Šauša O., Čechová K., Švajdlenková H., Mat'ko I., Petkova T., Boev V., Ilcheva V., Smutok O., Kukhazh Y., Gonchar M.
Acta Physica Polonica A
|
2017
|
vol. 132
|
issue 5
1515-1518
EN
Network properties of ureasil-based polymer matrixes suitable for construction of amperometric biosensors were probed by positron annihilation lifetime spectroscopy and swelling experiments. Temperature dependences of the ortho-positronium (o-Ps) lifetimes and their relative intensities were measured in a temperature range of 15-350 K. Glass transition temperatures and expansion coefficients of microscopical free-volume for the investigated polymers were determined. Differences in network behavior for the aged samples and the effect of chalcogenide (As₂S₃) particles on the free volume of ureasil network were observed. Swelling experiments using ethyl alcohol showed that the structure of the aged sample network had less swelling ability for the pure ureasil as well as composite. This suggests that the one of factors influencing swelling is the change of the basic ureasil network due to ageing. It is supposed that the network properties obtained by positron annihilation lifetime spectroscopy and swelling experiments could be very helpful to understand better the bio-functionality of the constructed biosensor based on the ureasil-chalcogenide glass composite.
first rewind previous Page / 1 next fast forward last
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.