Features in formation of Langmuir-Blodgett films and possible control and study of their properties directly in deposing them onto sub-strates are studied. Linearity of the dependence of polarization on the slope angle of the static dipole moment for C18H36O2 and C18H34O2 has been checked.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3366

Chuhaeva, I.V.

Dobromyslov, M.B.

Kuzmenko, A.P.

Electronic Sumy State University Institutional Repository

JOURNAL OF NANO- AND ELECTRONIC PHYSICS ЖУРНАЛ НАНО- ТА ЕЛЕКТРОННОЇ ФІЗИКИ Vol. 5 No 4, 04035(2pp) (2013) Том 5 № 4, 04035(2cc) (2013)   The article was reported at the International Conference «Physics and Technology of Nanomaterials and Structures», Kursk, 21-22 November, 2013 2077-6772/2013/5(4)04035(2) 04035-1  2013 Sumy State University Short Communication  Features in Formation and Properties of Langmuir-Blodgett Monolayers  A.P. Kuzmenko1, I.V. Chuhaeva1, M.B. Dobromyslov2  1 Southwest State University, 94, 50 Let Oktyabrya Str., 305040 Kursk, Russia 2 Pacific National University, 136, Tihookeanskaya Str., 680035, Khabarovsk, Russia  (Received 06 November 2013; published online 10 December 2013)  Features in formation of Langmuir-Blodgett films and possible control and study of their properties di-rectly in deposing them onto sub-strates are studied. Linearity of the dependence of polarization on the slope angle of the static dipole moment for C18H36O2 and C18H34O2 has been checked.  Keywords: Langmuir-Blodgett monolayers, phase transitions, electrical polarization, Stark effect, second harmonics.   PACS number: 68.47.Pe   1. INTRODUCTION  Synthesis of monolayered materials of organic, in-organic, and mixed nature is undoubtedly of great in-terest, which is due to the necessi-ty of obtaining unique set of properties required in electronics, optics, photovoltaics, micromechanics, membrane technolo-gies, applied chemis-try, biophysics, and other domains [1-3]. Such materials are formed by direct synthesis, crystallization, self-organization or Langmuir-Blodgett (LB) method. The present paper considers features in working installa-tions for the implementation of LB method and physical characteristics of obtained mono-layers.  2. HARDWARE AND ANALYSIS OF MONO- AND MULTILAYERED LB FILMS  Installation KSV NIMA makes it possible to form and study properties of LB films, measure characteris-tics of mono- and multila yers of organic substances on the surface of water subphase, make layerwise deposi-tion of films onto solid substrates. Basic units and func-tional interrelations are schematically shown in Fig. 1. The installation affords conditions for the stationary mode of monolayer formation from multiphase system “liquid medium-monolayer-air-condensed substrate”. Solution of liquid subphase (water) with surface at which monolayer from amphiphilic compounds sits is working medium.    Fig. 1 – Functional block diagram of installation KSV NIMA Langmuir-Blodgett The installation affords a uniform (0.1-270 mm/min velocity) compression (symmetrical or one-sided) of monolayer with moving barriers (3). Adjusting the ex-tent of barrier compression causes phase transitions in monolayer among the following states: gaseous – liquid crystal – solid crystal (Fig. 2). The monolayer deposi-tion velocity is dictated by an immersion mechanism (5) and varies in the range 0.1-100 mm/min. Quality of a substance being monolayered is secured by programmable control with PC (7) by both of the immersion mechanism with a substrate (5) and the extent of the barrier compression (3). A sensor (4) of surface pressure (Wilhelm’s scale), which is in the feedback circuit (6), affords parameter control. The magnitude of surface pressure is determined with an accuracy of 4 N/m within the range of 0 to150 mN/m. Pressure on the water surface (2), as monolayers are transferred to the substrate (5), is reduced in propor-tion to the substance content that forms the monolayer. To compensate for this substance reduction the moving barriers (3) automatically drift, supporting the surface pressure constant. Uniqueness of the LB method con-sists in the fact that the monolayer, with the help of barriers (3), is compressed until continuous film is formed with a dense packing of molecules. Specific mo-lecular area A in this film is virtually coincides  with the cross-section of a molecule. In this case, available, for instance, hydrocarbon radicals prove to be oriented virtually perpendicularly to the substrate surface. Interphase transitions are illustrated in Fig. 2 in which provided are isothermal dependencies (-А iso-therms) of surface pressure () on specific molecular area (А) at constant temperature. The isothermal dependence carries the information both of intermolecular interactions and reorientation, conformation, rearrangements, and other processes that describe the behavior of a complex molecule at the water surface. Extrapolation of linear portions on the dependence π-А that correspond to the monolayer compression in various phase states provides the value of A0 , namely, the area taken by one molecule. For example, according to -А isotherm obtained at room temperature stable layers for the subphase surface C60 appear at a compression of   25 mN/ms by forming crys-tal islets with an area per one molecule А  0.85 nm3 [4].  A.P. KUZMENKO, I.V. CHUHAEVA, M.B. DOBROMYSLOV J. NANO- ELECTRON. PHYS. 5, 04035 (2013)   04035-2  Table 1 – Check for linearity of polarizability dependence on the slope angle of the static dipole momentum for C18H36O2 и C18H34O2  Surfactant Density,g/cm3 Molecular mass, g/mole Momen-tum, D соs Coefficient, k Magni-tude, R2 5 45 60 Stearine acid 0.847 284.48 4.84 0.99 0.7 0.5 0.032 1 Oleic acid 0.895 282.46 1.69 0.012 0.99   Fig. 2 – Isothermal states in LB method: G – gaseous, LG – liquid-gaseous, L – liquid, LC – liquid-crystal, S – solid-crystal  Structural study of formed monolayered films with thicknesses of greater than 20 nm by X-ray and neu-tron diffractometry reveals information on the film thickness on the substrate, the number of molecular layers in it, repetition period, electronic density profile, localization of heavy atoms and typical molecular groups, the slope of carbon chains in layers, and the type of molecule packing into two-dimensional lattice. Thinner layers that are studied by slow electron dif-fraction technique and transmission electron microsco-py provide averaged data on the focused area of the radiation beam, and may cause defects and film de-struction. A special place is taken by small-angle scat-tering techniques, among other things, X-ray scatter-ing, which is applied to examine entities the size of 0.1 to 100 nm. Scanning tunneling microscopy and atomic-force microscopy being nondestructive methods feature high spatial resolution, making them much needed techniques for studying monolayered LB films [5-7].  LB films have various physical properties among which of special importance are the following ones: me-chanical (structural transformations), optical (parame-ters of orientation order of molecular fragments), and electrical (orientation of molecular dipoles and charge distribution across the monolayer cross-section).  For example, electrical polarization determined as р  (NA0cosψ)/М is inversely proportional to the mo-lecular mass M. Here NA is the Avogadro number,  is the monolayer density, 0 is a static molecular dipole moment, ψ is the angle between the molecular  dipole and normal to the film. Using expression for p, one can check if the condition of its linearity on the angle slope of the static dipole moment for most used in the LB method surfactants C18H36O2 и C18H34O2  is fulfilled. The calculation of this dependence has revealed that the highest reliability on linearity is characteristic for stearine acid, which is intensively used at monolay-er deposition. Optical methods for studying generation of the se-cond optical harmonic provide data on inversion cen-ters in monolayer; establish correlations between the relevant nonlinear susceptibility and the magnitude of polar ordering parameter. Generation of the second harmonic in polar multilayers in the absence of an ex-ternal field is feature of LB films. The intensity of the second harmonic is determined by expression      {   [(     )     ](     )    } , where  is the wavelength, n1 and n2 are the medium refractive indexes at the prime and double frequencies, respectively, l is the monolayer thickness, according to which the second harmonics intensity is linearly proportional to the number of minelayers. One more way with which formed LB mon-olayeres are characterized is the Stark effect. It has sensitivity that is enough for measuring on one mono-molecular layer. In this case the absorption of quantum of light is linearly dependent on the rotation angle 0:         (   )         on the applied electric field – quadratically dependent                with the shift of the straight (terms). Here h is the Plank constant, ν is linear frequency, E is the electric field intensity, Δ, Δ are changes in the dipole momentum and polariza-tion, respectively [8, 9].  3. CONCLUSION  It is shown that in forming LB films one can deter-mine their polarization and mono- and multilayered-ness, which makes it possible to create structures with preset properties that meet the practical demands.  REFERENCES  1. H. Motschmann, H. Mohwald, Handbook of Applied Sur-face and Colloid Chemistry 28, 629 (2001).  2. A.P. Girard-Egrot, S. Godoy, L.J. Blum, Adv. Colloid Inter-face Sci. 116, 205 (2005). 3. L.M. Blinov, V.M. Fridkin, S.P. Palto Phys.-Usp. 43 No3, 243 (2000). 4. Yu.S. Kaganovskiy, Yu.V. Ptitsyn, V.P. Seminozhenko, V.A. Tkachev, A.V. Tolmachev, JETP Lett. 60, 361 (1994). 5. T.J. Joncheray, K.M. Denoncourt, C. Mathieu, et. al, Langmuir 22, 9264 (2006). 6. Rute I.S. Romao, Q. Ferreira, J. Morgado, J.M.G. Martinho, Amelia M.P.S. Goncalves da Silva, J. Nanosci. Nanotech-nol. 11, 3151 (2011). 7. J.K. Basu, M.K. Sanyal, Phys. Report. 363, 1 (2002).  8. R. Capana, T.H. Richardson, Mater. Lett. 58, 3131 (2004). 9. M.K. Mukhopadhyay, M.K. Sanyal, T. Sakakibara, V. Leiner, R.M. Dalgliesh, S. Langridge, Phys. Rev. B 74, 014402 (2006). , mN/m  А, nm2 S-C L-C L L-G G 

Features in Formation and Properties of Langmuir-Blodgett Monolayers

SocioEconomic Challenges Journal (Sumy State University)

JOURNAL OF NANO- AND ELECTRONIC PHYSICS ЖУРНАЛ НАНО- ТА ЕЛЕКТРОННОЇ ФІЗИКИ 
Vol. 5 No 4, 04035(2pp) (2013) Том 5 № 4, 04035(2cc) (2013) 
 
 
The article was reported at the International Conference «Physics and Technology of Nanomaterials and Structures», Kursk, 21-22 November, 2013 
2077-6772/2013/5(4)04035(2) 04035-1  2013 Sumy State University 
Short Communication 
 
Features in Formation and Properties of Langmuir-Blodgett Monolayers 
 
A.P. Kuzmenko1, I.V. Chuhaeva1, M.B. Dobromyslov2 
 
1 Southwest State University, 94, 50 Let Oktyabrya Str., 305040 Kursk, Russia 
2 Pacific National University, 136, Tihookeanskaya Str., 680035, Khabarovsk, Russia 
 
(Received 06 November 2013; published online 10 December 2013) 
 
Features in formation of Langmuir-Blodgett films and possible control and study of their properties di-
rectly in deposing them onto sub-strates are studied. Linearity of the dependence of polarization on the 
slope angle of the static dipole moment for C18H36O2 and C18H34O2 has been checked. 
 
Keywords: Langmuir-Blodgett monolayers, phase transitions, electrical polarization, Stark effect, second 
harmonics. 
 
 PACS number: 68.47.Pe 
 
 
1. INTRODUCTION 
 
Synthesis of monolayered materials of organic, in-
organic, and mixed nature is undoubtedly of great in-
terest, which is due to the necessi-ty of obtaining 
unique set of properties required in electronics, optics, 
photovoltaics, micromechanics, membrane technolo-
gies, applied chemis-try, biophysics, and other domains 
[1-3]. Such materials are formed by direct synthesis, 
crystallization, self-organization or Langmuir-Blodgett 
(LB) method. The present paper considers features in 
working installa-tions for the implementation of LB 
method and physical characteristics of obtained mono-
layers. 
 
2. HARDWARE AND ANALYSIS OF MONO- 
AND MULTILAYERED LB FILMS 
 
Installation KSV NIMA makes it possible to form 
and study properties of LB films, measure characteris-
tics of mono- and multila yers of organic substances on 
the surface of water subphase, make layerwise deposi-
tion of films onto solid substrates. Basic units and func-
tional interrelations are schematically shown in Fig. 1. 
The installation affords conditions for the stationary 
mode of monolayer formation from multiphase system 
“liquid medium-monolayer-air-condensed substrate”. 
Solution of liquid subphase (water) with surface at 
which monolayer from amphiphilic compounds sits is 
working medium. 
 
 
 
Fig. 1 – Functional block diagram of installation KSV NIMA 
Langmuir-Blodgett 
The installation affords a uniform (0.1-270 mm/min 
velocity) compression (symmetrical or one-sided) of 
monolayer with moving barriers (3). Adjusting the ex-
tent of barrier compression causes phase transitions in 
monolayer among the following states: gaseous – liquid 
crystal – solid crystal (Fig. 2). The monolayer deposi-
tion velocity is dictated by an immersion mechanism 
(5) and varies in the range 0.1-100 mm/min. Quality of 
a substance being monolayered is secured 
by programmable control with PC (7) by both of the 
immersion mechanism with a substrate (5) and the 
extent of the barrier compression (3). A sensor (4) of 
surface pressure (Wilhelm’s scale), which is in the 
feedback circuit (6), affords parameter control. The 
magnitude of surface pressure is determined with an 
accuracy of 4 N/m within the range of 0 to150 mN/m. 
Pressure on the water surface (2), as monolayers are 
transferred to the substrate (5), is reduced in propor-
tion to the substance content that forms the monolayer. 
To compensate for this substance reduction the moving 
barriers (3) automatically drift, supporting the surface 
pressure constant. Uniqueness of the LB method con-
sists in the fact that the monolayer, with the help of 
barriers (3), is compressed until continuous film is 
formed with a dense packing of molecules. Specific mo-
lecular area A in this film is virtually coincides  with 
the cross-section of a molecule. In this case, available, 
for instance, hydrocarbon radicals prove to be oriented 
virtually perpendicularly to the substrate surface. 
Interphase transitions are illustrated in Fig. 2 in 
which provided are isothermal dependencies (-А iso-
therms) of surface pressure () on specific molecular area 
(А) at constant temperature. The isothermal dependence 
carries the information both of intermolecular interactions 
and reorientation, conformation, rearrangements, and 
other processes that describe the behavior of a complex 
molecule at the water surface. Extrapolation of linear 
portions on the dependence π-А that correspond to the 
monolayer compression in various phase states provides 
the value of A0 , namely, the area taken by one molecule. 
For example, according to -А isotherm obtained at room 
temperature stable layers for the subphase surface C60 
appear at a compression of   25 mN/ms by forming crys-
tal islets with an area per one molecule А  0.85 nm3 [4]. 
 A.P. KUZMENKO, I.V. CHUHAEVA, M.B. DOBROMYSLOV J. NANO- ELECTRON. PHYS. 5, 04035 (2013) 
 
 
04035-2 
 
Table 1 – Check for linearity of polarizability dependence on the slope angle of the static dipole momentum for C18H36O2 и C18H34O2 
 
Surfactant Density,g/cm3 Molecular 
mass, g/mole 
Momen-
tum, D 
соs Coefficient, 
k 
Magni-
tude, R2 5 45 60 
Stearine 
acid 
0.847 284.48 4.84 0.99 0.7 0.5 0.032 1 
Oleic acid 0.895 282.46 1.69 0.012 0.99 
 
 
Fig. 2 – Isothermal states in LB method: G – gaseous, LG – 
liquid-gaseous, L – liquid, LC – liquid-crystal, S – solid-crystal 
 
Structural study of formed monolayered films with 
thicknesses of greater than 20 nm by X-ray and neu-
tron diffractometry reveals information on the film 
thickness on the substrate, the number of molecular 
layers in it, repetition period, electronic density profile, 
localization of heavy atoms and typical molecular 
groups, the slope of carbon chains in layers, and the 
type of molecule packing into two-dimensional lattice. 
Thinner layers that are studied by slow electron dif-
fraction technique and transmission electron microsco-
py provide averaged data on the focused area of the 
radiation beam, and may cause defects and film de-
struction. A special place is taken by small-angle scat-
tering techniques, among other things, X-ray scatter-
ing, which is applied to examine entities the size of 0.1 
to 100 nm. Scanning tunneling microscopy and atomic-
force microscopy being nondestructive methods feature 
high spatial resolution, making them much needed 
techniques for studying monolayered LB films [5-7].  
LB films have various physical properties among 
which of special importance are the following ones: me-
chanical (structural transformations), optical (parame-
ters of orientation order of molecular fragments), and 
electrical (orientation of molecular dipoles and charge 
distribution across the monolayer cross-section).  
For example, electrical polarization determined as 
р  (NA0cosψ)/М is inversely proportional to the mo-
lecular mass M. Here NA is the Avogadro number,  is 
the monolayer density, 0 is a static molecular dipole 
moment, ψ is the angle between the molecular  dipole 
and normal to the film. Using expression for p, one can 
check if the condition of its linearity on the angle slope 
of the static dipole moment for most used in the LB 
method surfactants C18H36O2 и C18H34O2  is fulfilled. 
The calculation of this dependence has revealed 
that the highest reliability on linearity is characteristic 
for stearine acid, which is intensively used at monolay-
er deposition. 
Optical methods for studying generation of the se-
cond optical harmonic provide data on inversion cen-
ters in monolayer; establish correlations between the 
relevant nonlinear susceptibility and the magnitude of 
polar ordering parameter. Generation of the second 
harmonic in polar multilayers in the absence of an ex-
ternal field is feature of LB films. The intensity of the 
second harmonic is determined by expression 
     {
   [(     )     ]
(     )    
}
 
, where  is the wavelength, n1 
and n2 are the medium refractive indexes at the prime 
and double frequencies, respectively, l is the monolayer 
thickness, according to which the second harmonics 
intensity is linearly proportional to the number of 
minelayers. One more way with which formed LB mon-
olayeres are characterized is the Stark effect. It has 
sensitivity that is enough for measuring on one mono-
molecular layer. In this case the absorption of quantum 
of light is linearly dependent on the rotation angle 0: 
        (   )         on the applied electric field – 
quadratically dependent         
 
 
     with the shift 
of the straight (terms). Here h is the Plank constant, ν 
is linear frequency, E is the electric field intensity, Δ, 
Δ are changes in the dipole momentum and polariza-
tion, respectively [8, 9]. 
 
3. CONCLUSION 
 
It is shown that in forming LB films one can deter-
mine their polarization and mono- and multilayered-
ness, which makes it possible to create structures with 
preset properties that meet the practical demands. 
 
REFERENCES 
 
1. H. Motschmann, H. Mohwald, Handbook of Applied Sur-
face and Colloid Chemistry 28, 629 (2001).  
2. A.P. Girard-Egrot, S. Godoy, L.J. Blum, Adv. Colloid Inter-
face Sci. 116, 205 (2005). 
3. L.M. Blinov, V.M. Fridkin, S.P. Palto Phys.-Usp. 43 No3, 
243 (2000). 
4. Yu.S. Kaganovskiy, Yu.V. Ptitsyn, V.P. Seminozhenko, 
V.A. Tkachev, A.V. Tolmachev, JETP Lett. 60, 361 (1994). 
5. T.J. Joncheray, K.M. Denoncourt, C. Mathieu, et. al, 
Langmuir 22, 9264 (2006). 
6. Rute I.S. Romao, Q. Ferreira, J. Morgado, J.M.G. Martinho, 
Amelia M.P.S. Goncalves da Silva, J. Nanosci. Nanotech-
nol. 11, 3151 (2011). 
7. J.K. Basu, M.K. Sanyal, Phys. Report. 363, 1 (2002).  
8. R. Capana, T.H. Richardson, Mater. Lett. 58, 3131 (2004). 
9. M.K. Mukhopadhyay, M.K. Sanyal, T. Sakakibara, 
V. Leiner, R.M. Dalgliesh, S. Langridge, Phys. Rev. B 74, 
014402 (2006). 
, 
mN/m 
 
А, nm2 
S-C 
L-C 
L 
L-G 
G 


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Features in Formation and Properties of Langmuir-Blodgett Monolayers

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