Kamila Mikołajczuk
Magdalena Mieścicka
University of Natural Sciences and Humanities in Siedlce
Direction of Chemistry

Frank Laboratory of Neutron Physics
Supervisor of the project:
Aldona Rajewska, PhD

FLNP is the place where:
• ultracold neutrons were discovered;
• enhancement of the space parity violation effect in neutron resonances was found
• use the neutron as an instrument to investigate the structure and dynamics of condensed matter, including crystals and nanosystems, functional materials, complex liquids and polymers, rocks

Surfactants are compounds that lower the surface tension of a liquid, the interfacial tension between two liquids, or that between a liquid and a solid.

A micelle - the lipophilic tails of the surfactant molecules remain on the inside of the micelle due to unfavourable interactions. The polar
"heads" of the micelle, due to favourable interactions with water, form a hydrophilic outer layer that in effect protects the hydrophobic core of the micelle. The compounds that make up a micelle are typically amphiphilic in nature, meaning that not only are micelles soluble in protic solvents such as water but also in aprotic solvents as a reverse micelle.

Classical/Gemini
Surfactants ionic Non-ionic cationic anionic zwitterionic

Micellization, CMC point and Krafft point
Surfactants molecules occur as monomers in very diluted solution. However after exceed permissible concentration participles are spontaneous associated. They form aggregations called micelles.
Determined surfactant concentration cause micellization after exceed CMC point (critical micelle concentration).
Krafft point
The temperature (more precisely, narrow temperature range) above which the solubility of a surfactant rises sharply. At this temperature it becomes equal to the critical micelle concentration. It is best determined by locating the abrupt change in slope of a graph of the logarithm of the solubility against t or 1/T.

In this technique radiation is elasically scattered by a sample and the resulting scattering pattern is analysed to provide information about the size, shape and orientation of some component of the sample.
SANS are used in situations where the important physical aspects ( size, range of interaction etc.) occur at distances extanding typically from 10 to
1000 Å.

1 – two reflectors;
2 – zone of reactor with moderator;
3 – chopper;
4 – first collimator;
5 – vacuum tube;
6 – second collimator;
7 – thermostate;
8 – samples table;
9 – goniometer;
10-11 – Vn-standard;
12 – ring-wire detector;
13 – position-sensitve detector "Volga";
14 – direct beam detector.

What should we know about the experiment?
• Firstly the sample is prepared by chemists, who are responsible to determine a CMC and Krafft point, then physicists realized researchs in reactor
• The source of neutrons beam is plutionium (IV) oxide PuO
2 located in reactor which is
• Collimated neutron beam fall on a sample
• One part of radiation is scattered, second one is transmitted and third is absorbed
• Scattering beam is recorded by the detector
• On the basis of obtain results by the detector, we can determine ex. scattering angle, neutron intensity
• We obtain experimental plots then analyse their by GIFT programme
(Generalized Indirect Fourier Transformation)
• This analysis provide information about the shapes, aggregation number, size of micelles for the sample

Nonionic surfactant hepta (ethylene glycol) monodecyl ether (C
10 solutions.
E
7
)* in dilute heavy water
• Surfactant hepta (ethylene glycol) monodecyl ether (C
10 study with SANS method.
E
7
) was
• Solutions for concentrations: 0.17%, 0.5%, 1% was investigated at temperatures: 10 o C, 15 o C, 20 o C, 25 o C and 35 o C for each sample
(the temperature was kept constant with accuracy of ±0.5
o C).
• The measurements were made for the momentum transfer Q range
0.02 0.43 Å -1 .
• The CMC value for surfactant C
10
E
7 is equal 0.96 mmol/dm3,
*C10E7=>heptaethylene glycol monodecyl ether(C
24
H
50
O
8
)
Surfactant type C i
E j
CH
3
(CH
2
)
9
O(CH
2
CH
2
O)
7
H

0.5
0.4
0.3
0.2
C
10
E
7
+D
2
O
c=0.17%
10 o
C
15 o
C
20 o
C
25 o
C
35 o
C
0.1
0.1
Q [A
-1
]
Fig.1. Intensity of neutron scattering vs scattering vector for concentration c
1
=0.17% at temperatures: 10 o , 15 o , 20 o , 25 o , 30 o and 35 o C.
1

1
C
10
E
7
+D
2
O
c=0.5%
10 o
C
15 o
C
20 o
C
25 o
C
30 o
C
35 o
C
0.1
0.1
Q [A
-1
]
Fig.2. Intensity of neutron scattering vs scattering vector for concentration c
2
=0.5% at temperatures: 10 o , 15 o , 20 o , 25 o , 30 o and 35 o C.

1
0.1
0.1
Q [A
-1
]
Fig.3. Intensity of neutron scattering vs scattering vector for concentration c
3
=1% at temperatures: 10 o , 15 o , 20 o , 25 o , 30 o and 35 o C.
C
10
E
7
+D
2
O
c=1%
10 o
C
15 o
C
20 o
C
25 o
C
30 o
C
35 o
C

0.008
0.006
p (r)
0.004
0.002
10 deg
15 deg
20 deg
35 deg
25 deg
0.000
0 2 4 r [nm]
6 8
• Fig. 4. Pair distance distributon function (PDDF) for the C10E7
(c=0,17%) system from SANS measurements for temperatures 10,
15, 20, 25 and 35 Celsius degree

• If intensity of neurons scattering increases the number of micelles grow up in micellar solution
• For the bigger concentrations and temperatures the maximum have a higher value
• If the curve p(r) is symmethric – micelle have spherical shape
• Moreover, distance between zero point and point where curve p(r) cross axis r is equal to diameter of micelle
• When the curve is not symmetric it is example of micelle with ellipsoidal shape
• Received diagram is characteristc for ellipsoid micelles

• „Structure Analysis by Small-Angle X-Ray and Neutron
Scattering” L.A. Feigin and D.I. Svergun, Plenum Press,
New York and London
• Otto Glater and others Langmuire, 2000, 16, 8692-8701
„Nonionic Micelles near the Critical Point; Micellas
Growth and Attractive Interaction”
• A.Guiner, G. Fournet „Small- Angle Scattering of X-rays”,
John Wiley, 1955
• O.Glatter, O.Kratky „Small- Angle X-ray Scattering”
Academic Press, 1982
• „Small Angle Neutron Scattering” Stephen M.King ISIS
Facility, Rutheford Appleton Laboratory, December 1995