Structural and phase transitions in nanocluster ethanol samples at low temperatures
Results of neutron (SANS study) and x-ray diffraction experiments with nanocluster samples of deuteroethanol (C₂D₅OD) or ordinary pure ethanol (C₂H₅OH) are presented. A deuterated ethanol sample, formed via quick cooling of ethanol–helium mixture down to 1.6 K, had clusters with the size of d ~ 20...
Збережено в:
| Дата: | 2015 |
|---|---|
| Автори: | , , , , , |
| Формат: | Стаття |
| Мова: | English |
| Опубліковано: |
Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України
2015
|
| Назва видання: | Физика низких температур |
| Теми: | |
| Онлайн доступ: | https://nasplib.isofts.kiev.ua/handle/123456789/127936 |
| Теги: |
Додати тег
Немає тегів, Будьте першим, хто поставить тег для цього запису!
|
| Назва журналу: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Цитувати: | Structural and phase transitions in nanocluster ethanol samples at low temperatures / V. Efimov, A. Izotov, L. Mezhov-Deglin, V. Nesvizhevskii, O. Rybchenko, A. Zimin // Физика низких температур. — 2015. — Т. 41, № 6. — С. 603-607. — Бібліогр.: 23 назв. — англ. |
Репозитарії
Digital Library of Periodicals of National Academy of Sciences of Ukraine| id |
nasplib_isofts_kiev_ua-123456789-127936 |
|---|---|
| record_format |
dspace |
| spelling |
nasplib_isofts_kiev_ua-123456789-1279362025-06-03T16:29:05Z Structural and phase transitions in nanocluster ethanol samples at low temperatures Efimov, V. Izotov, A. Mezhov-Deglin, L. Nesvizhevskii, V. Rybchenko, O. Zimin, A. 10th International Conference on Cryocrystals and Quantum Crystals Results of neutron (SANS study) and x-ray diffraction experiments with nanocluster samples of deuteroethanol (C₂D₅OD) or ordinary pure ethanol (C₂H₅OH) are presented. A deuterated ethanol sample, formed via quick cooling of ethanol–helium mixture down to 1.6 K, had clusters with the size of d ~ 20–30 nm at liquid helium temperatures. After warming up to liquid nitrogen temperatures the gel decays into an amorphous white powder. It was observed that these powder samples remained in the amorphous state even after keeping at T ≤ 90 K for a long time (a few months). The neutron studies were supported by further x-ray investigations of the structure and the phase transitions in the highly dispersed powder samples, which were created via the decay of the gel samples of ordinary ethanol at temperatures above liquid nitrogen up to 150 K at saturated nitrogen gas pressure. Annealing of the “gel” sample during half an hour at a temperature of T ~ 110 K resulted in a phase transition to a monoclinic phase with the crystallite sizes ~30–40 nm. For comparison we studied the structure and phase transitions in “bulk” samples, prepared via quick freezing of liquid ethanol down to liquid nitrogen temperature. The “bulk” sample had a similar transition at T ~ 125 K, which is by 15 K higher than the temperature of the intensive phase transition in the “gel” sample. The mean grain size in the bulk material was d ≥ 60 nm. This work was supported in part by the Russian Foundation for Basic Research project 13-02-00378 and by the ILL, experiment 13-15-74. The authors are very obliged to C. Dewhurst, L. Porcar and the ILL team supporting the experiment on D-22 diffractometer. 2015 Article Structural and phase transitions in nanocluster ethanol samples at low temperatures / V. Efimov, A. Izotov, L. Mezhov-Deglin, V. Nesvizhevskii, O. Rybchenko, A. Zimin // Физика низких температур. — 2015. — Т. 41, № 6. — С. 603-607. — Бібліогр.: 23 назв. — англ. 0132-6414 PACS: 61.05.fg, 61.46.–w, 64.70.K– https://nasplib.isofts.kiev.ua/handle/123456789/127936 en Физика низких температур application/pdf Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України |
| institution |
Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| collection |
DSpace DC |
| language |
English |
| topic |
10th International Conference on Cryocrystals and Quantum Crystals 10th International Conference on Cryocrystals and Quantum Crystals |
| spellingShingle |
10th International Conference on Cryocrystals and Quantum Crystals 10th International Conference on Cryocrystals and Quantum Crystals Efimov, V. Izotov, A. Mezhov-Deglin, L. Nesvizhevskii, V. Rybchenko, O. Zimin, A. Structural and phase transitions in nanocluster ethanol samples at low temperatures Физика низких температур |
| description |
Results of neutron (SANS study) and x-ray diffraction experiments with nanocluster samples of deuteroethanol
(C₂D₅OD) or ordinary pure ethanol (C₂H₅OH) are presented. A deuterated ethanol sample, formed via
quick cooling of ethanol–helium mixture down to 1.6 K, had clusters with the size of d ~ 20–30 nm at liquid helium
temperatures. After warming up to liquid nitrogen temperatures the gel decays into an amorphous white
powder. It was observed that these powder samples remained in the amorphous state even after keeping
at T ≤ 90 K for a long time (a few months). The neutron studies were supported by further x-ray investigations
of the structure and the phase transitions in the highly dispersed powder samples, which were created via the decay
of the gel samples of ordinary ethanol at temperatures above liquid nitrogen up to 150 K at saturated nitrogen
gas pressure. Annealing of the “gel” sample during half an hour at a temperature of T ~ 110 K resulted
in a phase transition to a monoclinic phase with the crystallite sizes ~30–40 nm. For comparison we studied
the structure and phase transitions in “bulk” samples, prepared via quick freezing of liquid ethanol down
to liquid nitrogen temperature. The “bulk” sample had a similar transition at T ~ 125 K, which is by 15 K higher
than the temperature of the intensive phase transition in the “gel” sample. The mean grain size in the bulk material
was d ≥ 60 nm. |
| format |
Article |
| author |
Efimov, V. Izotov, A. Mezhov-Deglin, L. Nesvizhevskii, V. Rybchenko, O. Zimin, A. |
| author_facet |
Efimov, V. Izotov, A. Mezhov-Deglin, L. Nesvizhevskii, V. Rybchenko, O. Zimin, A. |
| author_sort |
Efimov, V. |
| title |
Structural and phase transitions in nanocluster ethanol samples at low temperatures |
| title_short |
Structural and phase transitions in nanocluster ethanol samples at low temperatures |
| title_full |
Structural and phase transitions in nanocluster ethanol samples at low temperatures |
| title_fullStr |
Structural and phase transitions in nanocluster ethanol samples at low temperatures |
| title_full_unstemmed |
Structural and phase transitions in nanocluster ethanol samples at low temperatures |
| title_sort |
structural and phase transitions in nanocluster ethanol samples at low temperatures |
| publisher |
Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України |
| publishDate |
2015 |
| topic_facet |
10th International Conference on Cryocrystals and Quantum Crystals |
| url |
https://nasplib.isofts.kiev.ua/handle/123456789/127936 |
| citation_txt |
Structural and phase transitions in nanocluster ethanol samples at low temperatures / V. Efimov, A. Izotov, L. Mezhov-Deglin, V. Nesvizhevskii, O. Rybchenko, A. Zimin // Физика низких температур. — 2015. — Т. 41, № 6. — С. 603-607. — Бібліогр.: 23 назв. — англ. |
| series |
Физика низких температур |
| work_keys_str_mv |
AT efimovv structuralandphasetransitionsinnanoclusterethanolsamplesatlowtemperatures AT izotova structuralandphasetransitionsinnanoclusterethanolsamplesatlowtemperatures AT mezhovdeglinl structuralandphasetransitionsinnanoclusterethanolsamplesatlowtemperatures AT nesvizhevskiiv structuralandphasetransitionsinnanoclusterethanolsamplesatlowtemperatures AT rybchenkoo structuralandphasetransitionsinnanoclusterethanolsamplesatlowtemperatures AT zimina structuralandphasetransitionsinnanoclusterethanolsamplesatlowtemperatures |
| first_indexed |
2025-11-25T15:51:18Z |
| last_indexed |
2025-11-25T15:51:18Z |
| _version_ |
1849778117215780864 |
| fulltext |
Low Temperature Physics/Fizika Nizkikh Temperatur, 2015, v. 41, No. 6, pp. 603–607
Structural and phase transitions in nanocluster ethanol
samples at low temperatures
V. Efimov1,2, A. Izotov1, L. Mezhov-Deglin1, V. Nesvizhevskii1,3, O. Rybchenko1,
and A. Zimin1,4
1Institute of Solid State Physics RAS, Chernogolovka, Moscow District, Russia
E-mail: victor_efimov@yahoo.co.uk
2Physics Department, Lancaster University, Lancaster, UK
3Institute Max von Laue–Paul Langevin, Grenoble, France
4Astrakhan State University, 20a Tatistcheva, Astrakhan, Russia
Received January 13, 2015, published online April 23, 2015
Results of neutron (SANS study) and x-ray diffraction experiments with nanocluster samples of deutero-
ethanol (C2D5OD) or ordinary pure ethanol (C2H5OH) are presented. A deuterated ethanol sample, formed via
quick cooling of ethanol–helium mixture down to 1.6 K, had clusters with the size of d ~ 20–30 nm at liquid he-
lium temperatures. After warming up to liquid nitrogen temperatures the gel decays into an amorphous white
powder. It was observed that these powder samples remained in the amorphous state even after keeping
at T ≤ 90 K for a long time (a few months). The neutron studies were supported by further x-ray investigations
of the structure and the phase transitions in the highly dispersed powder samples, which were created via the de-
cay of the gel samples of ordinary ethanol at temperatures above liquid nitrogen up to 150 K at saturated nitro-
gen gas pressure. Annealing of the “gel” sample during half an hour at a temperature of T ~ 110 K resulted
in a phase transition to a monoclinic phase with the crystallite sizes ~30–40 nm. For comparison we studied
the structure and phase transitions in “bulk” samples, prepared via quick freezing of liquid ethanol down
to liquid nitrogen temperature. The “bulk” sample had a similar transition at T ~ 125 K, which is by 15 K higher
than the temperature of the intensive phase transition in the “gel” sample. The mean grain size in the bulk mate-
rial was d ≥ 60 nm.
PACS: 61.05.fg Neutron scattering (including small-angle scattering);
61.46.–w Structure of nanoscale materials;
64.70.K– Solid-solid transitions.
Keywords: ethanol, amorphous structure transition, SANS, x-ray diffraction.
Introduction
Ethanol is an extremely interesting material for investi-
gating crystalline and orientational transitions. It has been
known that ethanol exhibits an interesting phase polymor-
phism. The fully disordered supercooled liquid transforms
into a structural glass upon quick cooling. The orientation-
ally disordered crystalline phase transforms from a rotator
phase to an orientational glass upon cooling at a moderate
rate. The stable orientational ordered crystal of monoclinic
phase was produced via very slow growth of the sample
at a temperature close to the melting point. There are
a lot of measurements of different type with ethanol samp-
les: x-ray diffraction [1–4], Raman spectroscopy [2], spe-
cific heat [3,5–10], complex dielectric susceptibility [11],
neutron scattering [3,5,12], thermal conductivity [13], light
and infrared reflection [14,15]. In fact, the most evident
experimental result is the existence of the stable monoclin-
ic crystalline phase at the temperature close to melting [1]
(fully ordered structure) and the amorphous state (glass
like state, supercooled liquid and so on) in a completely
disordered phase, which was formed by quenching faster
than 30 K/min [16]. All other rotational and structural or-
der–disorder transitions are very sensitive to cooling and
annealing procedures.
In this work we studied the processes of crystallization
of amorphous ethanol with different size of clusters. We
produced nanocluster samples of ethanol in the cryomatrix
© V. Efimov, A. Izotov, L. Mezhov-Deglin, V. Nesvizhevskii, O. Rybchenko, and A. Zimin, 2015
V. Efimov, A. Izotov, L. Mezhov-Deglin, V. Nesvizhevskii, O. Rybchenko, and A. Zimin
of helium via quick cooling of a mixture of ethanol vapor
with helium gas. For comparison, we measured the time of
transition to the monoclinic phase for a “bulk” ethanol
sample, produced via quick freezing of liquid ethanol. Our
investigation indicated that the temperature of intensive
transition depends drastically on the size of the nanopartic-
les in the sample and the sample preparation procedure.
Experimental results
Preparation of ethanol–helium “gel” samples
The methods for the impurity gel preparations was de-
scribed earlier [17]. The gel was prepared via condensation
of a gas mixture of ethanol vapor and 4He on the surface of
superfluid helium He II cooled below 1.8 K. The samples
were prepared in situ for subsequent studies by small-angle
neutron scattering (SANS) at liquid helium temperatures
in a special cryostat [18]. Initially the sample of the deu-
terated ethanol gel was prepared in the cell installed in
the middle part of the cryostat [19], where we placed a pair
of windows for visual control of the sample formation in-
side the quartz cell. The process of sample preparation
continued for one hour and we got a spongy soft matter
filling the whole cell (Fig. 1). The concentration of ethanol
molecules in the gel could be estimated from the volume of
liquid ethanol at the bottom of experimental cell measured
at the ambient temperature after posterior gel sample de-
cay; the volume was Veth ~ 0.5 cm3. Thus, the relative vol-
ume concentration was c = Veth/VG ~ 2%, where VG is the
volume of the experimental cell (D = 2.5 cm, h ~ 5 cm).
Small-angle neutron scattering
After the cell was filled we moved it to the bottom part
(tail) of the cryostat, which was made of aluminum and
thus was transparent for neutrons. The measurements were
performed at ILL using D22 instrument with at neutron
wavelengths of 4.8 and 6.1 Å. The angular distribution of
the intensity of neutron scattering I(q) allow estimating the
maximum size (diameter) of reflecting particles d. The
transition from “Porod scattering” (I(q) ~ q–4) [20] at large
angles (qd >> 1) to a less sharp angular dependences I(q)
(Guinier region [21]) took place at angles qRg < 1 (Fig. 2).
Here, Rg = (3/5)1/2R for spherical particles, and the particle
diameter is < 2.6/ .
From these experiments we could estimate that the ma-
ximum diameter of the deuteroethanol particles in the gel
was d ~ 20–30 nm. The right part of the I(q) curve in Fig. 2
corresponds to “large-angle” neutron scattering (scattering
on small particles). It is seen that the content of particles of
small sizes in the sample increased with heating from 1.6
to 4.2 K. A more detailed temperature dependence of the
neutron scattering at q = 0.6 Å–1 is shown in Fig. 3. A simi-
Fig. 1. Process of sample preparation. The sample fills the whole
cell. A filling tube can be seen in the upper part of the window.
Fig. 2. (Color online) Neutron scattering on C2D5OD gel near
the cell bottom. The temperature of He II in the cell is 1.6 K (cur-
ves 1 and 2). Curves 3 and 4 are results of measurements at 4.2 K.
106
104
102
100
10–2
10–2 10–1 100
10–4
10–3
| |, q Å–1
Radial Re-grouing: | |q
I,
cm
–1
1: #59485
2: #59483
3: #59529
4: #59527
Fig. 3. Temperature dependence of neutron scattering at large
angles (q = 0.6 Å–1) from the sample of deuteron–ethanol–helium
gel in during heating of liquid helium.
C D OD2 5
Neutron scattering
λ = 4.6 , = 0.6 Å Åq –1
0.015
0.010
0.005
0
I,
cm
–1
1.5 2.0 2.5 3.0 3.5 4.0 4.5
T, K
0.6 Position 1
0.6 Position 2
604 Low Temperature Physics/Fizika Nizkikh Temperatur, 2015, v. 41, No. 6
Structural and phase transitions in nanocluster ethanol samples at low temperatures
lar influence of temperature to “large-angle” neutron scatter-
ing was observed earlier for a deuterium-helium gel [22].
It is interesting that initially (at T = 1.6 K) the “large-
angle” scattering in the top part of the cell (43 mm from
the bottom) was negligible against the background. Warm-
ing the sample up to 4.2 K increased drastically the I(q)
and was the same as bottom points. This behavior indicates
that warming at liquid helium temperatures results in a splitt-
ing of large nanoparticles into smaller ones.
Decay of the ethanol–helium gel
In a set of SANS experiments we tried to find the tem-
perature, at which the impurity-helium gel starts to decay.
The main interest is related to the problem of interaction
between a polar impurity molecule and helium surround-
ing. One can assume that in He gas atmosphere at saturated
vapor pressure the sample keeps its shape until helium atoms
in bulk of the sample start “to leave” volume of the sample.
Then the gel frame should lose its stability. Unfortunately,
SANS measurements assume long neutron counting, and
thus this method is poorly compatible with rather fast natu-
ral warming of the cryostat towards liquid nitrogen tem-
peratures after liquid helium evaporation (~2 h). Therefore
we measured the neutron intensity in the center of direct
neutron beam, taking into account that the reduction in
number of neutrons, which are passing through the sample
directly (neutron transmission), would correspond to cer-
tain increase of their scattering. We measured the neutron
intensity in two points: near the cell bottom and also at the
height of 43 mm above it. The measuring time was only
1 min, so we should be careful with scanning the sample
density in different points. The results are shown in Fig. 4.
All changes in the beam intensity in points 1 and 3 were
small as long as liquid helium continued staying in the cell.
When the liquid evaporated, the temperature in the cell
began raising, and the gel started to release from the upper
part of the cell and it became more compact near the bot-
tom. At temperatures ~35 K the sample began to disinte-
grate and the decay stayed very intensive up to tempera-
tures of 80–100 K. The gel sample transformed to a white
powder, collecting at the bottom of the cell. The center of
the neutron beam didn’t touch the powder, and the intensi-
ty in points 1 and 3 stayed very close.
Afterward, we used the powder of pure ethanol pro-
duced via similar way for measurements of the phase tran-
sitions in the powder by the x-ray diffraction method. It
was observed that the ethanol powder could be stored un-
changed for a long time (for a few months) in liquid nitro-
gen for further experiments.
X-ray measurements
The structure of powder samples and the phase tran-
sitions under annealing were studied using the method of
x-ray powder diffraction. Initial samples were prepared
from ethanol in two different ways. One way of prepara-
tion of a “gel” sample was described above. We studied
“gel” sample powder after helium evaporation. The x-ray
diffraction spectra were obtained using Cu-Kα irradiation
in the nitrogen gas atmosphere.
The structure of as-prepared samples was amorphous.
Sometimes we observed a small amount of the water ice.
Apparently it formed on the sample surface from the water
vapors, which condensed during the cold sample transfer
from the container into the measuring cell.
All samples were kept in liquid nitrogen before x-ray
investigations, so the question about structure stability at
this temperature was important. The x-ray measurements
of the “gel” samples made directly after the sample prepa-
ration and after half a year holding in liquid nitrogen had
demonstrated that there was no difference between diffrac-
tion pictures of “virgin” and “conserved” samples.
In order to study dynamics of crystallization of an
amorphous phase a few series of annealing were carried
out. The temperatures of annealing were from 105 to
150 K, durations were from 15 min up to 7 h. X-ray meas-
urements were carried out after each annealing.
The time of the measurements of one of diffraction
scanning is up to some hours. This time is comparable with
time of phase transformation into a crystalline state at tem-
peratures above 105 K. Therefore all the diffraction meas-
urements were carried out at the temperature of liquid ni-
trogen. We annealed a sample at a fixed temperature
during certain time, after that cooled it down to 85 K and
carried out x-ray measurements.
These x-ray investigations allowed us to find the tem-
perature of intensive crystallization; for the “gel” sample it
was about 110 K. The typical process of phase transition of
ethanol powder samples, prepared through the gel, is
shown in Fig. 5.
Fig. 4. (Color online) The temperature dependence of neutron
intensity in the center of neutron beam in the process of sample
warming. A sketch in the right side is an illustration of the beam
position. Point 1 is the count near the cell bottom, point 3 is
the upper part of the cell.
7.1
7.0
6.9
6.8
6.7
6.6
6.5
6.4
6.3
6.2
6.1
102101100 103
2: #59486 3
1
Tλ THe T, K
Position 3
Position 1
Box Sum×10
9
B
ox
c
ou
nt
s\
St
d
m
on
Low Temperature Physics/Fizika Nizkikh Temperatur, 2015, v. 41, No. 6 605
V. Efimov, A. Izotov, L. Mezhov-Deglin, V. Nesvizhevskii, O. Rybchenko, and A. Zimin
As seen in Fig. 5, annealing at the temperature of 110 K
during half an hour results in crystallization of almost the
whole sample. The size of crystallites was about 30 nm and
didn’t depend considerably on annealing duration. Appar-
ently it is related to the size of particles in amorphous etha-
nol’s powder, which is prepared through “gel” procedure.
For comparison we prepared amorphous ethanol sam-
ples by rapid quenching of a liquid (“bulk” sample). A
quartz substrate with the depth = 0.3 mm was filled with
absolute ethanol. Then the sample was cooled down to
liquid nitrogen temperatures faster than 20 K/min and put
into x-ray diffractometer for studying the phase transfor-
mation at annealing. The x-ray diffraction patterns of ini-
tial amorphous phases of “bulk” and “gel” samples (Fig. 6)
are identical.
The x-ray diffraction patterns of amorphous phases of
“bulk” and “gel” samples (Fig. 6) indicated that the dis-
tance between ethanol molecules in both samples is close.
The process of annealing with subsequent x-ray meas-
urements of “bulk samples” was carried out using the same
procedure as for “gel” samples. The temperature of anne-
aling, at which phase transformation happened quickly
enough, was about 125 K that is higher by 15 degrees than
the temperature of intensive phase transition in the “gel”
sample.
The phase transition at heating results in formation of
the monoclinic phase in both cases. Diffraction spectra of
the obtained monoclinic phase are close to that described
in [1,4]. They differ a bit for various temperatures of an-
nealing and for samples obtained from “gel” and by direct
quick freezing. We believe that it is connected with various
ways of packing of ethanol molecules in a crystal cell.
The difference in temperatures of crystallization for
“gel” and “bulk” samples might be explained by two fac-
tors influencing on the dynamics of transition.
On the one hand, for particles of order of ten nanome-
ters in size, as in “gel” sample, the share of the molecules,
which are in surface layer, is rather great, so the role of
superficial energy is considerable. It can lead to essential
decrease in temperature of phase transition.
On the other hand, explanation is connected with the pro-
cedure of “gel” samples preparation. Ethanol molecules in
the ethanol–helium mixture are separated by helium atoms,
that impedes formation of H bonds, during the quick cool-
ing of this mixture. After removal of helium from a sample,
molecules of ethanol in amorphous phase “are frozen” in
the positions, but aren’t connected by O–H intermolecular
bonds. Therefore the formation of the crystalline phase
under annealing is just associated to the reorganization of
the ethanol molecules and does not require of additional
energy for breaking H bonds unlike crystallization of
the “bulk” amorphous samples (supercooled liquid). So, it
decreases the temperature of phase transition.
Fig. 5. (Color online) Transformation of amorphous ethanol “gel”
sample into monoclinic phase at annealing. In the bottom graphic
we plotted diffraction pictures for monoclinic ethanol (red curve, [1])
and hexagonal ice (blue curve).
“Gel” sample
Initial 85 K
Heat up to 105 K (15 )'
Heat up to 110 K (15 )'
Heat up to 110 K (30 )'
7000
6000
5000
4000
3000
2000
1000
0
1500
1000
500
0
2 , gradθ
10
10
20
20
0
0
40
40
50
N
, a
cc
ou
nt
s
N
, a
cc
ou
nt
s
Fig. 6. (Color online) Comparison of x-ray diffraction pictures of
amorphous ethanol samples prepared through “gel” procedure
and those prepared by freezing of liquid (“bulk” sample).
Fig. 7. (Color online) Transformation of an amorphous ethanol
“bulk” sample into monoclinic phase at annealing.
10
10
20
20
0
0
40
40
50
Initial 85 K
Annealing at 120 K (15 )'
Annealing at 125 K (15 )'
Annealing at 125 K (30 )'
1500
15000
10000
5000
25000
20000
1000
500
0
0
2 , gradθ
N
, a
cc
ou
nt
s
N
, a
cc
ou
nt
s
“Bulk” sample
606 Low Temperature Physics/Fizika Nizkikh Temperatur, 2015, v. 41, No. 6
Structural and phase transitions in nanocluster ethanol samples at low temperatures
Additional research is needed for resolving the structure
of various modifications of the monoclinic phase, which
are formed at different conditions from “gel” and “bulk”
amorphous samples, and for answering the question on na-
ture of so large difference in temperatures of the phase
transition.
Conclusions
We studied the phase transition of the ethanol powder
samples from amorphous to monoclinic phase. We formed
the ethanol samples by two methods: through the ethanol–
helium gel decay and by quick freezing of the liquid down
to the liquid nitrogen temperatures. Measurements of small-
angle neutron scattering (SANS) of deutorated ethanol
samples indicated that this procedure provided nanopartic-
les of ethanol with the size of the order of d = 20–30 nm,
relevant in particular for reflectors and thermalizers of
slow neutrons [23].
The decay of the nanoparticle gel occurs at tempera-
tures below liquid nitrogen temperatures. As a result we
got an amorphous powder, which stayed changeless at time
at least half a year in liquid nitrogen. The x-ray measure-
ments were done at the liquid nitrogen temperature, so we
are sure that the concentration of the crystalline phase didn’t
changed for the time of angle scanning. The size of the mo-
noclinic crystallines after phase transitions was 30–40 nm
that is close to the estimation from the SANS measure-
ments. So we could conclude that the size of nanoparticles
via gel preparation of the powder was of the order of some
tens nanometers. At the temperature 110 K at least 90%
of amorphous nanoparticles transmute into the crystalline
phase for one hour.
The “bulk amorphous samples” of ethanol, prepared by
quick cooling of the fluid, demonstrated shifting the tem-
perature of quick crystallization to higher values up to
T ~ 125 K. The mean size of crystalline particles after tran-
sition was rather large (> 60 nm).
This work was supported in part by the Russian Foun-
dation for Basic Research project 13-02-00378 and by the
ILL, experiment 13-15-74. The authors are very obliged to
C. Dewhurst, L. Porcar and the ILL team supporting the
experiment on D-22 diffractometer.
1. Per-Gunnar Joensson, Acta Cryst. B 32, 232 (1976).
2. A. Srinivasan, F.J. Bermejo, A. De Andres, J. Dawidovski,
J. Zuniga, and A. Griado, Phys. Rev. B 53, 8172 (1996).
3. F.J. Bermejo, A. Criado, R. Fayos, R. Fernandez-Parea, H.E.
Fischer, E. Suard, A. Guelyah, and J. Zuniga, Phys. Rev. B
56, 11536 (1997).
4. M. Ramos, I. Shmyt’ko, E. Arnautova, R.J. Jimenez-Rioboo,
V. Rodriguez-Mora, S. Vieira, and M.J. Capitan, J. Non-
Cryst. Solids 352, 4769 (2006).
5. M.A. Ramos, S. Vieira, F.J. Bermejo, J. Dawidowski, H.E.
Fischer, H. Schober, M.A. Gonzalez, C.K. Loong, and D.L.
Price, Phys. Rev. Lett. 78, 82 (1996).
6. V. Rodrigues-Mora and M. Ramos, J. Non-Cryst. Solids 354,
263 (2008).
7. B. Kabtoul, R.J. Jimenez-Rioboo, and M. Ramos, Philos.
Mag. 88, 4197 (2008).
8. E. Perez-Enciso and M. Ramos, Thermochimica Acta 461,
50 (2007).
9. C. Talon, M. Ramos, and S. Vieira, Phys. Rev. B 66, 012201
(2002).
10. B. Kabtoul and M. Ramos, Phys. Status Solidi A 208, 2249
(2011).
11. M.A. Miller, M. Jimenez-Ruiz, F.J. Bermejo, and N.O. Berge,
Phys. Rev. B 57, R13977 (1998).
12. R. Fayos, F.J. Bermejo, J. Dawidowski, H.E. Fischer, and
M.A. Gonzalez, Phys. Rev. Lett. 77, 3823 (1996).
13. A.I. Krivchikov, O.A. Korolyuk, and I.V. Sharapova, Fiz.
Nizk. Temp. 38, 95 (2012) [Low Temp. Phys. 38, 74 (2012)].
14. A. Drobyshev, A. Aldiyarov, K. Katpaeva, E. Korshikov, V.
Kurnosov, and D. Sokolov, Fiz. Nizk. Temp. 39, 919 (2013)
[Low Temp. Phys. 39, 714 (2013)].
15. A. Aldiyarov, A. Drobyshev, E. Korshikov, V. Kurnosov,
and D. Sokolov, Phys. Solid State 54, 1387 (2012).
16. O. Haida, H. Suga, and S. Seki, J. Chem. Thermodynamics 9,
1133 (1977).
17. V. Efimov and L. Mezhov-Deglin, Method of Preparation of
Nanoparticles from Gases and Vapor of Fluids, Patent
No. 2399581 (2010).
18. V. Efimov, L. Mezhov-Deglin, and A. Lokhov, Combining
Cryostat for Neutron Investigation, PTE (2015) (in press).
19. V. Efimov, L. Mezhov-Deglin, A. Lokhov, V. Nesvizhevsky
and C. Dewhurst, Adv. High Energy Phys. (2014) (in press).
20. G. Porod, Kolloid-Zeitschrift 124, 83 (1951).
21. A. Gunier and G. Fournet, Small-Angle Scattering of X-Rays,
JohnWiley & Sons (1955).
22. L.P. Mezhov-Deglin, V.B. Efimov, A.V. Lokhov, A.A. Lev-
chenko, G.V. Kolmakov, L.V. Abdurakhimov, M.Y. Brazh-
nikov, E.V. Lebedeva, R. May, V.V. Nesvizhevsky, A.V. Mu-
zychka, E.V. Lychagin, and A.V. Strelkov, J. Low Temp.
Phys. 150, 206 (2008).
23. V.V. Nesvizhevsky, Phys. At. Nucl. 65, 400 (2002).
Low Temperature Physics/Fizika Nizkikh Temperatur, 2015, v. 41, No. 6 607
Introduction
Experimental results
Preparation of ethanol–helium “gel” samples
Small-angle neutron scattering
Decay of the ethanol–helium gel
X-ray measurements
Conclusions
|