XIV
h
International Conference on Molecular Spectroscopy, Białka Tatrzańska 2017
153
T1: P–20
Synthesis and photochemistry studies of the intelligent luminescent
molecular sensors for monitoring of polymerization processes
Joanna Ortyl
1
, Monika Topa
1
, Maciej Pilch
1
, Anna Chachaj-Brekiesz
2
,
Mariusz Galek
3
, Filip Petko
3
, and Roman Popielarz
1
1
Faculty of Chemical Engineering and Technology, Cracow University of Technology, Warszawska
24, 30-155 Cracow, Poland, e-mail: jortyl@chemia.pk.edu.pl
2
Faculty of Chemistry, Jagiellonian University, R. Ingardena 3, 30-060 Cracow, Poland
3
Photo HiTech Ltd., Life Science Park, M. Bobrzyńskiego 14, 30-348 Cracow, Poland
Fluorescence spectroscopy is an important analytical technique that has been widely used in a
variety of applications, such as biomedicine, biology, and science, which makes it unique thanks to
extraordinary sensitivity and selectivity, short delay time (<10
–9
s), and the fact that it is neither
invasive nor destructive, so it can be used for the in-situ measurements. When the fluorescence
emission of these molecules is sensitive to changes of properties, such as polarity, viscosity, pH, or
electric potential, they can be used for detecting such changes in their microenvironment, and they are
called luminescent or fluorescent probes. As long as these probes can follow processes of practical
interest, they can be employed as sensors, if the information given by the measure of fluorescence
adequately reflects the changes in the system.
Extremely interesting and important application of luminescent sensors is the research of testing
polymeric materials by fluorescence spectroscopy. Currently, strict control of the quality of raw
materials and the final cured polymeric products is required for high production standards. Therefore,
there is a high demand for a quick and reliable method of polymerization progress monitoring that
would be applicable directly in production lines. Fluorescence Probe Technology is the answer to this
type of need, because it is based on the use of fluorescent probes as molecular sensors and quanta of
light for information transfer between the probe molecules and the monitoring system. The
fluorescent probes react on changes occurring in their vicinity within nanoseconds. Hence, the
fluorescent sensors meet the requirements of measurement speed.
In the FPT method, changes of luminescence characteristics of appropriate molecular sensors,
caused by changes of polarity or microviscosity of the medium the probe is dissolved in, are
monitored in real time. The changes in the probe response usually correlate very well with the
changes of other parameters occurring in the system. For example, during polymerization of
monomers, the probe molecules interact with the monomer and polymer molecules, present in the
probe vicinity, by various Van der Waals and dipolar interactions that cause stabilization of excited
states of the probe molecules by solvation. With the polymerization progress, the degree of solvation
of the excited probe molecules changes, that causes change of their energy at the moment of light
emission, and consequently, change of fluorescence characteristics. Hence, the quanta of light emitted
by the probe molecules carry information about the changes that have occurred in the reacting system.
In the case of most of monomers, when a fluorescent probe is dissolved in a monomer, and the
monomer is polymerized, the system polarity decreases, because monomers are usually more polar
than the corresponding polymers. Consequently, the fluorescence spectrum of the probe shifts
towards shorter wavelengths, while the shift magnitude is proportional to the extent of the change that
have occurred in the system. This change can be traced with an appropriate rapid-scan fluorimeter
that allows monitoring of the polymerization progress in real time. The main objective of this research
is synthesis, characterization and investigations of compounds that exhibit luminescence strongly
dependent on changes in their environment during polymerization processes.
Keywords: luminescence; molecular probe; fluorescence; polymerization; photopolymerization
Acknowledgment
This work was supported by the Foundation for Polish Science (Warsaw, Poland) within the project
POWROTY (Contract No. POWROTY/2016-1/4).
XIV
h
International Conference on Molecular Spectroscopy, Białka Tatrzańska 2017
154
T1: P–21
Vibrational spectroscopy of the aluminum oxynitride materials with
different stoichiometry
Alan Wilmański
1
, Jolanta Nieroda
1
, Andrzej Koleżyński
1
,
Maciej Sitarz
1
, and Mirosław M. Bućko
1
1
AGH University of Science and Technology, Faculty of Materials Science and Ceramics,
30 Mickiewicza Av., 30-059 Krakow, Poland, e-mail: jolanta.nieroda@agh.edu.pl
Aluminum oxynitride, γ-alon, is a spinel-type structure solid solution of Al
2
O
3
and AlN. Due
to its good mechanical properties and high chemical resistance γ-alon has a great potential
application in high-performance structural ceramics as well as refractory material. It was stated
that the “ideal” γ-alon, which had the stoichiometry Al
3
O
3
N, did not exist. The general model of
the γ-alon structure is based on the cubic spinel-type one, with space group Fd3m. In such
structure the O and N atoms are randomly distributed at the 32e sites, and the Al atoms occupy
the 8a and 16d sites. A few more detailed models of the γ-alon structure were described. In the
Constant Anion Model the 32e sites are fully occupied, although the positions of the anions are
not ideal and correspond to a deformed face-centered cubic structure, whereas the aluminum
vacancies are distributed over the octahedral sites. In the Constant Cation Model the octahedral
and tetrahedral cation sites are always fully occupied and the predominant defects are oxygen or
nitrogen interstitials.
The main purpose of the work was to study the structure (XRD, Raman) of materials with
different Al
2
O
3
:AlN ratio and subsequent verification of the models mentioned above.
Aluminum and corundum powder mixture was subjected to self-propagated high-
temperature synthesis (SHS) in nitrogen atmosphere. The content of aluminum in the mixture
was 20 mass%. The SHS-derived powder, composed of 76 mass% of γ-alon, 19 mass% of
corundum and 5 mass% of aluminum nitride, were ground with addition of different amount of
corundum to obtain a series of powders with formal AlN:Al
2
O
3
molar ratio from 27:73 to 39:61.
The powders were isostatically compacted and then pressureless sintered at 1850ºC for 2h in
nitrogen atmosphere.
X-ray diffraction analysis showed that all samples were composed of γ-alon only and linear
relationship between formal AlN:Al
2
O
3
molar ratio and the γ-alon unit cell constant confirmed
monotonic changes in stoichiometry of the aluminum oxynitride phase. Analysis of Raman
experimental spectra, supported by theoretical calculations confirmed the conclusions of XRD
studies.
Acknowledgment
This work was financially supported by the AGH University of Science and Technology as a part of
statutory activities of the Department of Ceramics and Refractory Materials (project no. 11.11.160.617).
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