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1-decanol lyotropic liquid crystalline systems
Journal of Molecular Liquids 200 (2014) 425–430
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Journal of Molecular Liquids journal homepage: www.elsevier.com/locate/molliq
Comparative investigations of phase states, mesomorphic and morphologic properties in hexadecyltrimethyl ammonium bromide/water and hexadecyltrimethyl ammonium bromide/water/1-decanol lyotropic liquid crystalline systems Arif Nesrullajev Muğla University, Faculty of Natural Sciences, Department of Physics, Laboratory of Liquid and Solid Crystals, TR-48170 Kötekli, Muğla, Turkey
a r t i c l e
i n f o
Article history: Received 11 June 2014 Received in revised form 15 October 2014 Accepted 26 October 2014 Available online 28 October 2014 Keywords: Liquid crystals Optical microscopy Texture Phase equilibrium Lyotropic phase transitions Anisometric micelles
a b s t r a c t In this work the phase equilibriums, the mesomorphic and morphologic properties of the binary hexadecyltrimethyl ammonium bromide/water and ternary hexadecyltrimethyl ammonium bromide/water/1-decanol lyotropic systems have been studied. The shape of micelles in the lyotropic phase has been estimated. Typical textures of the nematic–calamitic, nematic–discotic, hexagonal and lamellar mesophases and the phase diagrams of these lyotropic systems are presented. © 2014 Elsevier B.V. All rights reserved.
1. Introduction Lyotropic systems are the binary and/or multicomponent compositions, which are based on amphiphile, polar or/and non-polar solvent and other components (cosurfactant, non-organic salt, optical active material etc.). Under convenient temperature and concentration conditions these systems form lyotropic isotropic phases and lyotropic anisotropic liquid crystalline mesophases [1–7]. The structural units of these mesophases are the anisometric rod-like and disc-like micelles. Changes of temperature and concentration lead to a change of the shapes, sizes, packing character and spatial structures of the anisometric micelles [5–12]. Definite temperature and concentration sequence of lyotropic mesophases are determined by the phase diagrams. The phase diagrams of lyotropic liquid crystals are usually very diverse and complex, and consist of various types of the isotropic phases and anisotropic mesophases. Different structural properties, type of the physical anisotropy and differences in spatial symmetry lead to differences in the physical properties of lyotropic phases and mesophases. Therefore the studies of the phase states of lyotropic systems and also the comparative investigations of connection between the microscopic and macroscopic properties of lyotropic phases and mesophases are
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http://dx.doi.org/10.1016/j.molliq.2014.10.036 0167-7322/© 2014 Elsevier B.V. All rights reserved.
important topics in the physics and physical chemistry of lyotropic systems. On the other hand lyotropic liquid crystalline mesophases are highly sensitive and mobile not only to the change of temperatures and concentrations but also to different external effects and boundary conditions. Such sensitivity and mobility of lyotropic mesophases make lyotropic systems important and interesting objects from both fundamental and application points of view. In this work we are interested in the phase equilibrium of the binary hexadecyl trimethyl ammonium bromide (HTAB)/water (H2O) and ternary HTAB/H2O/1-decanol (DeOH) lyotropic systems, and the character of the typical textures of lyotropic mesophases, which take place in these systems. We are also interested in the magneto-morphologic properties of these mesophases and the shape of micelles in the abovementioned lyotropic systems. Results of such investigations are presented in this work.
2. Experimental Hexadecyl trimethyl ammonium bromide (cat. No. Sigma Ultra H9151) and 1-decanol (cat. No. 803463) were purchased from Sigma and Merck respectively. These materials have the high degree of purity and therefore were used without further purification. Water, which was used as the general solvent, was triple distilled and deionized.
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The preparation process of the lyotropic liquid crystalline systems under investigations followed known procedures. HTAB and H2O by precision balance were weighed into glass ampoules with an accuracy of ±10−4 g. After homogenization for some days at 315.0 ± 0.1 K in a thermostat, DeOH was added in the HTAB + H2O mixture for obtaining the ternary system. All of the binary and ternary lyotropic mixtures were periodically mixed in hermetically closed ampoule by a shaker and kept in a thermostat at 315 K for one week. Homogeneity of the obtained lyotropic mixtures was examined by the crossed polarizers and by studies of the typical textures, using a polarizing optical microscope. The samples as the micro-slides were used in this work. The thickness of liquid crystalline layer in the micro-slides was 20 μm. The samples were hermetically closed at once after filling by liquid crystalline system. Investigations of the mesomorphic and thermo-morphologic properties of the HTAB/H2O and HTAB/H2O/DeOH lyotropic liquid crystalline systems have been carried out using the polarizing optical microscopy (POM) method. The set-up consisted of a trinocular polarizing microscope with orthoscopic/conoscopic observations, a micro-photographic system and a Berek compensator from Olympus Optical Co., λ-plates (λ = 137 μm and λ = 530 μm), optical filters, heater-thermostat with digital temperature control system, differential Cu–Co thermocouples, power supply and multi-meters. For investigations of the dynamics of magnetically induced and aligned textures of liquid crystalline mesophases, special magnetooptical set-up has beet used. The samples were kept by stable temperature as 299.0 ± 0.1 K during the magnetic field influence. The peculiarities of the typical and magnetically induced textures of lyotropic mesophases, the optical signs and the disclinations of strength for various singularities, taking place in the textures, have been studied using the optical mapping (OM) method. The OM method was presented and described in [13–15] and was widely used in [15–19] for detailed investigations of the morphologic and structural peculiarities of liquid crystalline textures. In order to estimate the shape of micelles in the lyotropic phases and also to get the better understanding of the orientational character of these micelles under the shear flow we have analyzed the electrical conductivity anisotropy of the micelles, which is a well-known classical method. The details of this method can be found elsewhere [20–22]. This method is known to be related to anisometric character of the rod-like and disc-like (plate-like) character of the micelles in the lyotropic phases and also to be based on the fact that such micelles have translational mobility in the shear flow. Under the framework of this method, first the electrical conductivity of micelles is measured along three mutually perpendicular directions, then anisometric character is determined by identifying the sign of relative change in the electrical conductivity value [20–26]. In Fig. 1 we present the scheme of the coaxial cuvette, consisting of a rotor, a stator and electrodes. The electrodes allow one to determine the electrical conductivity anisotropy along the direction of the velocity gradient (namely along the X-direction), along the direction of the shift flow (along the Y-direction), and
Fig. 1. Scheme of the coaxial couette for the X (a), Y (b) and Z (c) directions.
along the direction which is perpendicular both to the shift flow direction and to the direction of the velocity gradient (along the Z-direction). We would like to note, that the above-mentioned method is similar to the method of determination of the micelle shape by the optical birefringence of anisometric micelles in the shear flow [27]. 3. Results and discussions In this work, the phase states, and the mesomorphic and morphologic properties of the HTAB/H2O and HTAB/H2O/DeOH lyotropic liquid crystalline systems have been studied. Our objectives were as follows. The phase diagrams, based on HTAB, are presented in a number of works [28–37]. However, the number, types and sequence of mesophases on these phase diagrams are different. Additionally, the concentration regions and the interface boundaries of lyotropic phases and mesophases on these diagrams are also different. Namely, for the HTAB/H2O/DeOH lyotropic systems isotropic micellar L1 phase, and hexagonal E and lamellar D mesophases have been found in [28]. Besides, in [28] for this system by zero DeOH concentration (i.e. for the HTAB/H2O system) only L1 phase and E mesophase are presented. For the HTAB/H2O lyotropic system a) L1 phase, and E and some nematic mesophases in [29]; b) L1 phase, and E and nematic–calamitic NC mesophases in [30]; c) L1 phase, and E and deformed hexagonal mesophase in [31]; d) L1 phase, and E, some nematic and lamellar D mesophases in [32]; e) L1 phase and E mesophase in [33, 34]; f) L1 and bicontinuous cubic V1 phases, and E, NC and D mesophases in [35]; g) L1 phase, and E and some nematic mesophases in [36]; and h) some cubic phase, and E and D mesophases in [37] have been found. Because of such variety of the mesomorphic properties and the phase states in the HTAB/H2O and HTAB/H2O/DeOH lyotropic systems, we carried out the investigations on the mesomorphic and morphologic properties, and the phase states of these systems. Investigations showed that the HTAB/H2O system exhibits isotropic micellar L1 phase, and NC and E mesophases. L1 phase, and NC and E mesophases in this lyotropic system take place in strongly definite concentration and temperature intervals. Between L1 phase and NC mesophase, and also between NC and E mesophases the lyotropic phase transitions and transition regions take place. The number and sequence of these phase and mesophases coincide with the number and sequence of phase and mesophases, observed in [30]. In Fig. 2 the phase diagram of the HTAB/H2O lyotropic system is presented. As it is seen in this figure, by an increase of HTAB concentration in the HTAB/H2O system, the L1 phase → NC mesophase → E mesophase concentration sequence has been observed. This sequence corresponds to the character of micelle transformations by an increase of the amphiphile concentration. Structural units of NC mesophase are the rod-like micelles with definite length; structural units of E mesophase are the
Fig. 2. Phase diagram of HTAB/H2O lyotropic system. Shaded regions are the transition regions between lyotropic states.
A. Nesrullajev / Journal of Molecular Liquids 200 (2014) 425–430
rod-like micelles with quasi-indefinite length [28,38–43]. NC and E mesophases are optical uniaxial and are characterized by the negative optical anisotropy. NC mesophase in the HTAB/H2O system exhibits typical schlieren texture (Fig. 3a). Such type of textures has been observed in various lyotropic systems for NC mesophase in [12,29,44–46]. This texture consists of the thread-like formations, singular points and small uniform regions. In this texture singularities with fourfold brushes and the disclination of strength as S = ±1, and also singularities with twofold brushes and the disclination of strength as S = ± 1/2 take place. By the application of external magnetic field as 6.6 kG parallel to the reference surfaces of the sandwich-cell, the homeotropic uniform alignment of NC mesophase was performed. In Fig. 4, the conoscopic picture of this texture is presented. In the uniform regions, the rod-like micelles are oriented perpendicularly to the reference surfaces of the micro-slides. In this case, the director is oriented perpendicularly to the reference surfaces of the micro-slides and amphiphile molecules in the rod-like micelles are oriented parallel to these surfaces. Such arrangement of the optical axis and amphiphile molecules is cause of the negative optical birefringence (Δn = n|| – n⊥ b 0) in NC mesophase. E mesophase in the HTAB/H2O system exhibits a fibrous texture (Fig. 3b). This texture is specific for E mesophase, has low birefringence and consists of the prolonged filament-like formations and uniform regions with the planar and titled orientation. Optical investigations showed that the filament-like formations have been nonhomogeneously distributed in volume of the microslide. Such type of texture for E mesophase has been observed in various lyotropic systems [28,47–52]. Investigations showed that the addition of DeOH in the HTAB/H2O lyotropic system leads to an increase in the order of the liquid crystalline mesophases and to an appearance of nematic–discotic ND and D mesophases in strongly definite concentration and temperature intervals. As is known, structural units of ND mesophase are the disc-like micelles with definite sizes; structural units of D mesophase are the disclike (plate-like) micelles with quasi-indefinite diameter [6,28,53,54]. ND and D mesophases are optical uniaxial and are characterized by the positive optical anisotropy. So, the HTAB/H2O/DeOH lyotropic system exhibits L1 phase, and NC, E, ND and D mesophases. In Fig. 5 the phase diagram of the HTAB/H2O/DeOH lyotropic system is presented. This phase diagram for zero concentration of DeOH is in full conformity with phase diagram of the HTAB/H2O system (Fig. 2). NC mesophase in HTAB/H2O/DeOH lyotropic system exhibits typical schlieren texture (Fig. 6a). This type of the schlieren texture is the same as texture of above-mentioned mesophase in the HTAB/H2O lyotropic system. As it is noted above, this type of texture was observed for NC mesophase in [12,29,44–46]. Besides, textures of such type have been observed in a large number of amphiphile + water + aliphatic alcohol lyotropic systems for NC mesophase in [29,45,47]. E mesophase in the HTAB/H2O/DeOH lyotropic system exhibits the fibrous texture (Fig. 6b), which is some similar texture presented in
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Fig. 4. Conoscopic picture of homeotropic aligned texture of NC mesophase in the HTAB/H2O lyotropic system.
Fig. 3b. Such type of texture in E mesophase for ternary lyotropic systems has been also observed in [19,51,52]. But as is seen from comparison of Figs. 3b and 6b, these fibrous textures have some different peculiarities. Namely, in the fibrous texture of the ternary lyotropic system the availability of rather large regions with the planar alignment takes place. This difference in the fibrous textures of E mesophase for binary and ternary lyotropic systems indicates on the effect of aliphatic alcohol additions on the morphologic properties of E mesophase. ND mesophase in the HTAB/H2O/DeOH lyotropic system exhibits the schlieren texture (Fig. 6c). Such type of textures for lyotropic nematic mesophases has been observed by a number of scientists in various lyotropic systems for ND mesophase [29,42,48,55,56]. As is seen from comparison of Fig. 6a and c, the schlieren textures of NC and ND mesophases are sufficiently similar. But, by the application of external magnetic field as 6.6 kG parallel to the reference surfaces of the sandwich-cell, the planar uniform alignment of ND mesophase was performed. In Fig. 7, planar alignment texture of ND mesophase is presented. In the uniform regions, the disc-like micelles are oriented perpendicular to the reference surfaces of the micro-slides. In this case, the director is oriented parallel to the reference surfaces of the microslides and amphiphile molecules in the disc-like micelles are oriented parallel to these surfaces. Such arrangement of the optical axis and amphiphile molecules is cause of the positive optical birefringence (Δn = n|| − n⊥ N 0) for ND mesophase. Such difference in the sign of the optical anisotropy is a fundamental distinction between the optical and orientational properties of NC and ND mesophases. D mesophase in the HTAB/H2O/DeOH lyotropic system exhibits texture, which is presented in Fig. 6d. This texture consists of the so-called “oily streak” formations. The oily streak formations are the birefringent bands, which form the net on the pseudo-isotropic background. Such
Fig. 3. Typical textures of NC (a) and E (b) mesophases in the HTAB/H2O lyotropic system. Temperature 300.5 K; crossed polarizers; magnification ×100.
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Fig. 7. Planar aligned texture of ND mesophase in the HTAB/H2O/DeOH lyotropic system. Temperature 300.0 K; crossed polarizers; magnification ×100.
Fig. 5. Phase diagram of the HTAB/H2O/DeOH lyotropic system.
type of texture is specific for D mesophase and has been observed by a number of scientists in various liquid crystalline systems [49,51,52, 57–61]. For the control and confirmation of an availability of the rod-like and disc-like micelles in the corresponding regions (regions of E, D, NC and ND mesophases) of the phase diagrams, presented in Figs. 2 and 5, the method of the electrical conductivity anisotropy in the orientational shear flow has been used. As an example, in Figs. 8, 9, and 10 these dependences for the X-, Y- and Z-directions are presented for E, NC, ND and D mesophases. As seen in these figures, the electrical conductivity
anisotropy increases with increasing rotational frequency which claims that an increase in the rotational frequency leads to an increase in the degree of orientational order of anisometric micelles under the shift flow. Besides, from Figs. 8 and 9, it is evident that the electrical conductivity anisotropy in the E and NC mesophases is negative along both Xand Z-directions and while it is positive along the Y-direction. On the other hand for D and ND mesophases the electrical conductivity anisotropy is negative along the X-direction and is positive along both the Yand Z-directions (see Fig. 10). Thus electrical conductivity vs rotational frequency data (Figs. 8, 9, 10) provide information on the availability of lyotropic mesophases containing the rod-like and disc-like (plate-like) micelles in corresponding regions of the phase diagrams (Figs. 2, 5) [20,21,23,25,62,42,53,63]. It is important to note, that the shear flow has not only orientational effect on anisometric micelles of lyotropic mesophases, but can also have deforming effect on these micelles. Such situation was theoretically studied in [20,21,23]. In accordance with theoretical approach [20,21, 23], if the rod-like and disc-like (plate-like) micelles are not deformed by
Fig. 6. Typical textures of NC (a), E (b), ND (c) and D (d) mesophases in the HTAB/H2O/DeOH lyotropic system. Temperature 299.6 K; crossed polarizers; magnification ×100.
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Fig. 9. The electrical conductivity anisotropy vs. rotational frequency for NC mesophase in the HTAB/H2O (a) and HTAB/H2O/DeOH (b) lyotropic systems. Fig. 8. The electrical conductivity anisotropy vs. rotational frequency for E mesophase in the HTAB/H2O (a) and HTAB/H2O/DeOH (b) lyotropic systems.
the flow, the following correlations between the electrical conductivity anisotropy in the X-, Y- and Z-directions, are valid σ X −σ 0 σ Z −σ 0 1 σ Y −σ 0 ¼ ¼ σ 2 σ σ 0
0
ð1Þ
0
length (NC mesophase) and definite diameter (ND mesophase) [64, 66]. The absence of deformation for micelles of ND and NC mesophases under the shear flow is an indicator of the rigid peculiarities of the anisometric micelles with definite sizes [24,40,62,66]. On the other hand, the availability of deformation of micelles in the D and E mesophases is related to the flexibility of spacious micelles [67–72].
for the rod-like micelles and σ Y −σ 0 σ Z −σ 0 1 σ X −σ 0 ¼ ¼ σ 2 σ σ 0 0 0
ð2Þ
for the disc-like (plate-like) micelles. Here σ Xσ−σ 0 , σ Yσ−σ 0 and σ Zσ−σ 0 are the 0 0 0 electrical conductivity anisotropies in the X-, Y- and Z-directions, accordingly. As it is seen from Figs. 8–10, for both HTAB/H2O and HTAB/H2O/ DeOH lyotropic systems the electrical conductivity anisotropy satisfies Eqs. (1) and (2) in the NC and ND mesophases along the X-, Y- and Z-directions while in the E and D mesophases those equations are not satisfied. These facts are indicative of the deformation effect of the shear flow on the anisometric micelles with quasi-indefinite length (E mesophase) and quasi-indefinite diameter (D mesophase). Such a deformation under the shear flow has been reported by several groups for disc-like (plate-like) micelles in the D mesophase [53,64], for the rod-like micelles in the E mesophase [63] and for aqueous mixture of anionic/nonionic surfactant system with anisometric formations [65]. In other respects, it must be stressed that the shear flow does not have deformation effect on the anisometric micelles with definite
4. Conclusion In this work, the phase states and mesomorphic properties of the HTAB/water and the HTAB/water/DeOH lyotropic systems have been investigated and phase diagrams of these systems have been constructed. In the HTAB/water lyotropic system L1 phase, and E and NC mesophases have been found; in the HTAB/water/DeOH lyotropic system L1 phase, and E, NC, ND and D mesophases have been found. The morphologic and structural properties of lyotropic mesophases, taking place in these lyotropic systems, have been studied. Peculiarities of the typical textures of these mesophases have been investigated using the POM and OM techniques. Orientational properties of NC and ND mesophases in the external magnetic field have been investigated. For control and confirmation of an availability of the rod-like and disc-like micelles in the corresponding regions of the phase diagrams, presented in Figs. 2 and 5, the shapes of structural units as the rod-like micelles in E and NC mesophases and as the disc-like (plate-like) micelles in ND and D mesophases were estimated. The method of the electrical conductivity anisotropy in the orientational shear flow has been used.
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Fig. 10. The electrical conductivity anisotropy vs. rotational frequency for ND (a) and D (b) mesophases in the HTAB/H2O/DeOH lyotropic systems.
References [1] S. Friberg, Organized Solutions: Surfactants in Science and Technology, CRC Press, New York, 1992. [2] A.G. Petrov, The Lyotropic State of Matter. Molecular Physics and Living Matter Physics, Gordon & Breach Sci., London — New York, 1999. [3] A.M. Figueiredo Neto, S.R.A. Salinas, The Physics of Lyotropic Liquid Crystals: Phase Transitions and Structural Properties, Oxford University Press, Oxford, 2005. [4] S.K. Wiedmer, M.L. Riekkola, Anal. Chem. 69 (1997) 1577–1584. [5] A. Panatta, V.M. Coiro, F. Mazza, Chem. Phys. Lett. 200 (1992) 130–134. [6] R. Bartolino, M. Meuti, G. Chidichimo, G.A. Ranieri, in: V. Degiorgio, M. Corti (Eds.), Physics of Amphiphiles: Micelles, Vesicles and Microemulsions, North Holland Press, Amsterdam/Oxford/New York/Tokyo, 1985, p. 524. [7] S.T. Hyde, in: K. Holmberg (Ed.), Handbook of Applied Surface and Colloid Chemistry, J. Wiley & Sons, Singapore, 2001, p. 299. [8] G. Montalvo, M. Valiente, E. Rodenas, J. Colloid Interface Sci. 172 (1995) 495–501. [9] G. Montalvo, M. Valiente, E. Rodenas, J. Colloid Interface Sci. 203 (1998) 294–299. [10] D.A. Doshi, A. Gibaud, V. Goletto, M. Lu, H. Gerung, B. Ocko, S.M. Han, C.J. Brinker, J. Am. Chem. Soc. 125 (2003) 11646–11655. [11] M. Angel, H. Hoffmann, M. Löbl, H. Thurn, I. Wunderlich, Progr. Colloid Interface. Sci. 69 (1988) 12–28. [12] M.R. Kuzma, A. Saupe, Handbook of Liquid Crystal, in: P.J. Collings, J.S. Patel (Eds.), Oxford University Press, New York/Oxford, 1997, p. 237. [13] J. Nehring, A. Saupe, J. Chem. Soc. Faraday Trans. 68 (1972) 1–15. [14] J.E. Zimmer, Disclinations in Lamellar Liquid Crystals(Ph.D. Thesis) Pardue University, W.Lafayette, Indiana, 1978.
[15] J.L. White, J.E. Zimmer, Carbon 16 (1978) 469–475. [16] J.E. Zimmer, J.L. White, Adv. Liq. Cryst. 5 (1982) 159–213. [17] J. Lydon, Handbook of Liquid Crystals, in: D. Demus, J. Goodby, G.W. Gray, H.-W. Spiess, V. Vill (Eds.), IIB, Willey-VCH, Weinheim, 1998, p. 981. [18] A. Nesrullajev, M. Tepe, D. Abukay, N. Kazancı, D. Demirhan, F. Büyükkılıç, Appl. Phys. A 71 (2000) 161–167. [19] P. Özden, A. Nesrullajev, Ş. Oktik, Phys. Rev. E. 82 (2010) (061710-1–061710-8). [20] K.G. Götz, K. Heckmann, J. Colloid Sci. 13 (1958) 266–272. [21] K. Heckmann, K.G. Götz, Z. Elektrochem. 62 (1958) 281–288. [22] H. Rehage, Rheologische untersuchungen an viscoelastischen Tensidlösungen(PhD Dissertation) Bayreuth University, Bayreuth, 1982. [23] G. Schwarz, Z. Phys. 145 (1958) 563–584. [24] A. Nesrullajev, Lyotropic Mesomorphism and Electro-Physics of Lyotropic Liquid Crystalline Systems(DSc Dissertation) Institute of Physics, Academy of Sciences, Baku, 1992. [25] K. Heckmann, Discuss. Faraday Soc. 25 (1958) 71–73. [26] V.V. Voytilov, A.A. Trusov, Kolloid J. 67 (1985) 455–461. [27] Y.G. Frolov, Colloid Chemistry, Chemistry Publ., Moscow, 1982. [28] P. Ekwall, Adv. Liq. Cryst. 1 (1975) 1–142. [29] G. Hertel, H. Hoffmann, Progr. Colloid Polym. Sci. 76 (1988) 123–131. [30] G. Hertel, Lyotrope nematische Phasen. Der Zusammenhang zwischen Molekülstruktur und Phasenverhalten(PhD Dissertation) Bayreuth University, Bayreuth, 1989. [31] X. Auvray, C. Petipas, R. Anthore, I. Ricco, A. Lattes, J. Phys. Chem. 93 (1989) 7458–7464. [32] T. Wolf, B. Klauβner, G. Von Bünau, Progr. Colloid Polym. Sci. 83 (1990) 176–180. [33] A.B. Cortés, M. Valiente, E. Rodenas, Langmuir 15 (1999) 6658-6603. [34] O. Canãdas, M. Valiente, E. Rodenas, J. Colloid Interface Sci. 203 (1998) 294–298. [35] K. Hiltrop, in: H.-S. Kitzerow, C. Bahr (Eds.), Chirality in Liquid Crystals, Springer, Berlin, 2001, p. 447. [36] E. Nativ-Roth, O. Regev, R. Yerushalmi-Rozen, Chem. Commun. (2008) 2037–2039. [37] R. Xsu, W. Pank, J. Yu, Q. Huo, J. Chen, Chemistry of Zeolites and Related Porous Materials: Synthesis and Structure, John Wiley & Sons, Singapore, 2007. [38] A.M. Figueiredo Neto, L. Amaral, Mol. Cryst. Liq. Cryst. 95 (1983) 129–141. [39] Y. Hendrikx, J. Charvolin, M. Rawiso, L. Liebert, M.S. Holmes, J. Phys. Chem. 87 (1983) 3991–3999. [40] A.S. Sonin, Usp. Fiziol. Nauk 153 (1987) 273–310; Sov. Phys. Usp. 30 (1987) 875–912. [41] A. Nesrullajev, N. Kazancı, T. Yıldız, Mater. Chem. Phys. 80 (2003) 710–713. [42] A. Nesrullajev, Mater. Chem. Phys. 123 (2010) 546–550. [43] E.V. Generalova, E.L. Kitaeva, A.N. Nesrullajev, A.S. Sonin, Colloid J. 52 (1990) 958–960. [44] H. Hoffmann, G. Oetter, B. Schwandner, Progr. Colloid Polym. Sci. 73 (1987) 95–106. [45] A. Nesrullajev, S. Oktik, Cryst. Res. Technol. 42 (2007) 44–49. [46] A.R. Sampaio, A.J. Palangana, R.C. Visconini, Mol. Cryst. Liq. Cryst. 408 (2004) 45–51. [47] http://wapedia.mobi/en/Hexagonal_phase. [48] A. Nesrullajev, M. Tepe, N. Kazancı, H.M. Çakmak, D. Abukay, Mater. Chem. Phys. 65 (2000) 125–129. [49] A. Nesrullajev, M. Okcan, N. Kazanci, J. Mol. Liq. 108 (2003) 313–332. [50] S.T. Hyde, Handbook of Applied Surface and Colloid Chemistry, in: K. Holmberg (Ed.), John Wiley & Sons, New York, 2001, p. 299. [51] S.K. Ghosh, Influence of Strongly Bound Counterions on the Phase Behavior of Ionic Amphiphiles(PhD Thesis) Raman Research Institute, Bangalore, 2007. [52] R. Krishnaswamy, S.K. Ghosh, S. Lakshmanan, V.A. Raghunathan, A.K. Sood, Langmuir 21 (2005) 10439–10443. [53] A. Nesrullajev, J. Mol. Liq. 187 (2013) 337–342. [54] G. Burducea, Rom. Rep. Phys. 56 (2004) 66–86. [55] A. Nesrullajev, Lyotropic Liquid Crystals: amphiphilic Systems, Ege University Press, Izmir, 2007. [56] G. Bartusch, H.-G. Dörfler, H. Hoffmann, Progr. Colloid Polym. Sci. 89 (1992) 307–314. [57] J.C. Wittmann, B. Lotz, F. Candau, A.J. Kovacs, J. Polym. Sci. 20 (1982) 1341–1344. [58] H.-D. Dörfler, A. Göpfert, Colloid Polym. Sci. 278 (2000) 1085–1096. [59] H.D. Dörfler, Adv. Colloid Interface Sci. 98 (2002) 285–340. [60] S. Ujiie, Y. Yano, Chem. Commun. (2000) 79–80. [61] D. Constantin, P. Davidson, C. Chaneac, Langmuir 26 (2010) 4586–4589. [62] V.N. Tsvetkov, Hard-Chain Polymer Molecules, Science Publ., Moscow, 1986. [63] A. Nesrullajev, Tenside Surfactants Deterg. 47 (2010) 179–183. [64] A. Nesrullajev, Kolloid J. 54 (1992) 125–132. [65] J. Crawshaw, G. Meeten, Rheol. Acta 46 (2006) 183–193. [66] G.B. Thurston, P. Munk, J. Chem. Phys. 52 (1970) 2359–2365. [67] S. Ozeki, S. Ikeda, Colloid Polym. Sci. 262 (1984) 409–417. [68] A. Flamberg, R. Pecora, J. Chem. Phys. 88 (1984) 3026–3033. [69] W. Van De Sande, A. Persoons, J. Phys. Chem. 89 (1985) 404–409. [70] T. Imae, T. Kamiya, S. Ikeda, J. Colloid Interface Sci. 108 (1985) 215–225. [71] T. Imae, S. Ikeda, Colloid Polym. Sci. 265 (1987) 1090–1098. [72] M. Lukaschek, D.A. Grabowski, C. Schmidt, Langmuir 11 (1995) 3590–3594.
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Comparative investigations of phase states, mesomorphic and morphologic properties in hexadecyltrimethyl ammonium bromide/water and hexadecyltrimethyl ammonium bromide/water/1-decanol lyotropic liquid crystalline systems Arif Nesrullajev Muğla University, Faculty of Natural Sciences, Department of Physics, Laboratory of Liquid and Solid Crystals, TR-48170 Kötekli, Muğla, Turkey
a r t i c l e
i n f o
Article history: Received 11 June 2014 Received in revised form 15 October 2014 Accepted 26 October 2014 Available online 28 October 2014 Keywords: Liquid crystals Optical microscopy Texture Phase equilibrium Lyotropic phase transitions Anisometric micelles
a b s t r a c t In this work the phase equilibriums, the mesomorphic and morphologic properties of the binary hexadecyltrimethyl ammonium bromide/water and ternary hexadecyltrimethyl ammonium bromide/water/1-decanol lyotropic systems have been studied. The shape of micelles in the lyotropic phase has been estimated. Typical textures of the nematic–calamitic, nematic–discotic, hexagonal and lamellar mesophases and the phase diagrams of these lyotropic systems are presented. © 2014 Elsevier B.V. All rights reserved.
1. Introduction Lyotropic systems are the binary and/or multicomponent compositions, which are based on amphiphile, polar or/and non-polar solvent and other components (cosurfactant, non-organic salt, optical active material etc.). Under convenient temperature and concentration conditions these systems form lyotropic isotropic phases and lyotropic anisotropic liquid crystalline mesophases [1–7]. The structural units of these mesophases are the anisometric rod-like and disc-like micelles. Changes of temperature and concentration lead to a change of the shapes, sizes, packing character and spatial structures of the anisometric micelles [5–12]. Definite temperature and concentration sequence of lyotropic mesophases are determined by the phase diagrams. The phase diagrams of lyotropic liquid crystals are usually very diverse and complex, and consist of various types of the isotropic phases and anisotropic mesophases. Different structural properties, type of the physical anisotropy and differences in spatial symmetry lead to differences in the physical properties of lyotropic phases and mesophases. Therefore the studies of the phase states of lyotropic systems and also the comparative investigations of connection between the microscopic and macroscopic properties of lyotropic phases and mesophases are
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http://dx.doi.org/10.1016/j.molliq.2014.10.036 0167-7322/© 2014 Elsevier B.V. All rights reserved.
important topics in the physics and physical chemistry of lyotropic systems. On the other hand lyotropic liquid crystalline mesophases are highly sensitive and mobile not only to the change of temperatures and concentrations but also to different external effects and boundary conditions. Such sensitivity and mobility of lyotropic mesophases make lyotropic systems important and interesting objects from both fundamental and application points of view. In this work we are interested in the phase equilibrium of the binary hexadecyl trimethyl ammonium bromide (HTAB)/water (H2O) and ternary HTAB/H2O/1-decanol (DeOH) lyotropic systems, and the character of the typical textures of lyotropic mesophases, which take place in these systems. We are also interested in the magneto-morphologic properties of these mesophases and the shape of micelles in the abovementioned lyotropic systems. Results of such investigations are presented in this work.
2. Experimental Hexadecyl trimethyl ammonium bromide (cat. No. Sigma Ultra H9151) and 1-decanol (cat. No. 803463) were purchased from Sigma and Merck respectively. These materials have the high degree of purity and therefore were used without further purification. Water, which was used as the general solvent, was triple distilled and deionized.
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The preparation process of the lyotropic liquid crystalline systems under investigations followed known procedures. HTAB and H2O by precision balance were weighed into glass ampoules with an accuracy of ±10−4 g. After homogenization for some days at 315.0 ± 0.1 K in a thermostat, DeOH was added in the HTAB + H2O mixture for obtaining the ternary system. All of the binary and ternary lyotropic mixtures were periodically mixed in hermetically closed ampoule by a shaker and kept in a thermostat at 315 K for one week. Homogeneity of the obtained lyotropic mixtures was examined by the crossed polarizers and by studies of the typical textures, using a polarizing optical microscope. The samples as the micro-slides were used in this work. The thickness of liquid crystalline layer in the micro-slides was 20 μm. The samples were hermetically closed at once after filling by liquid crystalline system. Investigations of the mesomorphic and thermo-morphologic properties of the HTAB/H2O and HTAB/H2O/DeOH lyotropic liquid crystalline systems have been carried out using the polarizing optical microscopy (POM) method. The set-up consisted of a trinocular polarizing microscope with orthoscopic/conoscopic observations, a micro-photographic system and a Berek compensator from Olympus Optical Co., λ-plates (λ = 137 μm and λ = 530 μm), optical filters, heater-thermostat with digital temperature control system, differential Cu–Co thermocouples, power supply and multi-meters. For investigations of the dynamics of magnetically induced and aligned textures of liquid crystalline mesophases, special magnetooptical set-up has beet used. The samples were kept by stable temperature as 299.0 ± 0.1 K during the magnetic field influence. The peculiarities of the typical and magnetically induced textures of lyotropic mesophases, the optical signs and the disclinations of strength for various singularities, taking place in the textures, have been studied using the optical mapping (OM) method. The OM method was presented and described in [13–15] and was widely used in [15–19] for detailed investigations of the morphologic and structural peculiarities of liquid crystalline textures. In order to estimate the shape of micelles in the lyotropic phases and also to get the better understanding of the orientational character of these micelles under the shear flow we have analyzed the electrical conductivity anisotropy of the micelles, which is a well-known classical method. The details of this method can be found elsewhere [20–22]. This method is known to be related to anisometric character of the rod-like and disc-like (plate-like) character of the micelles in the lyotropic phases and also to be based on the fact that such micelles have translational mobility in the shear flow. Under the framework of this method, first the electrical conductivity of micelles is measured along three mutually perpendicular directions, then anisometric character is determined by identifying the sign of relative change in the electrical conductivity value [20–26]. In Fig. 1 we present the scheme of the coaxial cuvette, consisting of a rotor, a stator and electrodes. The electrodes allow one to determine the electrical conductivity anisotropy along the direction of the velocity gradient (namely along the X-direction), along the direction of the shift flow (along the Y-direction), and
Fig. 1. Scheme of the coaxial couette for the X (a), Y (b) and Z (c) directions.
along the direction which is perpendicular both to the shift flow direction and to the direction of the velocity gradient (along the Z-direction). We would like to note, that the above-mentioned method is similar to the method of determination of the micelle shape by the optical birefringence of anisometric micelles in the shear flow [27]. 3. Results and discussions In this work, the phase states, and the mesomorphic and morphologic properties of the HTAB/H2O and HTAB/H2O/DeOH lyotropic liquid crystalline systems have been studied. Our objectives were as follows. The phase diagrams, based on HTAB, are presented in a number of works [28–37]. However, the number, types and sequence of mesophases on these phase diagrams are different. Additionally, the concentration regions and the interface boundaries of lyotropic phases and mesophases on these diagrams are also different. Namely, for the HTAB/H2O/DeOH lyotropic systems isotropic micellar L1 phase, and hexagonal E and lamellar D mesophases have been found in [28]. Besides, in [28] for this system by zero DeOH concentration (i.e. for the HTAB/H2O system) only L1 phase and E mesophase are presented. For the HTAB/H2O lyotropic system a) L1 phase, and E and some nematic mesophases in [29]; b) L1 phase, and E and nematic–calamitic NC mesophases in [30]; c) L1 phase, and E and deformed hexagonal mesophase in [31]; d) L1 phase, and E, some nematic and lamellar D mesophases in [32]; e) L1 phase and E mesophase in [33, 34]; f) L1 and bicontinuous cubic V1 phases, and E, NC and D mesophases in [35]; g) L1 phase, and E and some nematic mesophases in [36]; and h) some cubic phase, and E and D mesophases in [37] have been found. Because of such variety of the mesomorphic properties and the phase states in the HTAB/H2O and HTAB/H2O/DeOH lyotropic systems, we carried out the investigations on the mesomorphic and morphologic properties, and the phase states of these systems. Investigations showed that the HTAB/H2O system exhibits isotropic micellar L1 phase, and NC and E mesophases. L1 phase, and NC and E mesophases in this lyotropic system take place in strongly definite concentration and temperature intervals. Between L1 phase and NC mesophase, and also between NC and E mesophases the lyotropic phase transitions and transition regions take place. The number and sequence of these phase and mesophases coincide with the number and sequence of phase and mesophases, observed in [30]. In Fig. 2 the phase diagram of the HTAB/H2O lyotropic system is presented. As it is seen in this figure, by an increase of HTAB concentration in the HTAB/H2O system, the L1 phase → NC mesophase → E mesophase concentration sequence has been observed. This sequence corresponds to the character of micelle transformations by an increase of the amphiphile concentration. Structural units of NC mesophase are the rod-like micelles with definite length; structural units of E mesophase are the
Fig. 2. Phase diagram of HTAB/H2O lyotropic system. Shaded regions are the transition regions between lyotropic states.
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rod-like micelles with quasi-indefinite length [28,38–43]. NC and E mesophases are optical uniaxial and are characterized by the negative optical anisotropy. NC mesophase in the HTAB/H2O system exhibits typical schlieren texture (Fig. 3a). Such type of textures has been observed in various lyotropic systems for NC mesophase in [12,29,44–46]. This texture consists of the thread-like formations, singular points and small uniform regions. In this texture singularities with fourfold brushes and the disclination of strength as S = ±1, and also singularities with twofold brushes and the disclination of strength as S = ± 1/2 take place. By the application of external magnetic field as 6.6 kG parallel to the reference surfaces of the sandwich-cell, the homeotropic uniform alignment of NC mesophase was performed. In Fig. 4, the conoscopic picture of this texture is presented. In the uniform regions, the rod-like micelles are oriented perpendicularly to the reference surfaces of the micro-slides. In this case, the director is oriented perpendicularly to the reference surfaces of the micro-slides and amphiphile molecules in the rod-like micelles are oriented parallel to these surfaces. Such arrangement of the optical axis and amphiphile molecules is cause of the negative optical birefringence (Δn = n|| – n⊥ b 0) in NC mesophase. E mesophase in the HTAB/H2O system exhibits a fibrous texture (Fig. 3b). This texture is specific for E mesophase, has low birefringence and consists of the prolonged filament-like formations and uniform regions with the planar and titled orientation. Optical investigations showed that the filament-like formations have been nonhomogeneously distributed in volume of the microslide. Such type of texture for E mesophase has been observed in various lyotropic systems [28,47–52]. Investigations showed that the addition of DeOH in the HTAB/H2O lyotropic system leads to an increase in the order of the liquid crystalline mesophases and to an appearance of nematic–discotic ND and D mesophases in strongly definite concentration and temperature intervals. As is known, structural units of ND mesophase are the disc-like micelles with definite sizes; structural units of D mesophase are the disclike (plate-like) micelles with quasi-indefinite diameter [6,28,53,54]. ND and D mesophases are optical uniaxial and are characterized by the positive optical anisotropy. So, the HTAB/H2O/DeOH lyotropic system exhibits L1 phase, and NC, E, ND and D mesophases. In Fig. 5 the phase diagram of the HTAB/H2O/DeOH lyotropic system is presented. This phase diagram for zero concentration of DeOH is in full conformity with phase diagram of the HTAB/H2O system (Fig. 2). NC mesophase in HTAB/H2O/DeOH lyotropic system exhibits typical schlieren texture (Fig. 6a). This type of the schlieren texture is the same as texture of above-mentioned mesophase in the HTAB/H2O lyotropic system. As it is noted above, this type of texture was observed for NC mesophase in [12,29,44–46]. Besides, textures of such type have been observed in a large number of amphiphile + water + aliphatic alcohol lyotropic systems for NC mesophase in [29,45,47]. E mesophase in the HTAB/H2O/DeOH lyotropic system exhibits the fibrous texture (Fig. 6b), which is some similar texture presented in
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Fig. 4. Conoscopic picture of homeotropic aligned texture of NC mesophase in the HTAB/H2O lyotropic system.
Fig. 3b. Such type of texture in E mesophase for ternary lyotropic systems has been also observed in [19,51,52]. But as is seen from comparison of Figs. 3b and 6b, these fibrous textures have some different peculiarities. Namely, in the fibrous texture of the ternary lyotropic system the availability of rather large regions with the planar alignment takes place. This difference in the fibrous textures of E mesophase for binary and ternary lyotropic systems indicates on the effect of aliphatic alcohol additions on the morphologic properties of E mesophase. ND mesophase in the HTAB/H2O/DeOH lyotropic system exhibits the schlieren texture (Fig. 6c). Such type of textures for lyotropic nematic mesophases has been observed by a number of scientists in various lyotropic systems for ND mesophase [29,42,48,55,56]. As is seen from comparison of Fig. 6a and c, the schlieren textures of NC and ND mesophases are sufficiently similar. But, by the application of external magnetic field as 6.6 kG parallel to the reference surfaces of the sandwich-cell, the planar uniform alignment of ND mesophase was performed. In Fig. 7, planar alignment texture of ND mesophase is presented. In the uniform regions, the disc-like micelles are oriented perpendicular to the reference surfaces of the micro-slides. In this case, the director is oriented parallel to the reference surfaces of the microslides and amphiphile molecules in the disc-like micelles are oriented parallel to these surfaces. Such arrangement of the optical axis and amphiphile molecules is cause of the positive optical birefringence (Δn = n|| − n⊥ N 0) for ND mesophase. Such difference in the sign of the optical anisotropy is a fundamental distinction between the optical and orientational properties of NC and ND mesophases. D mesophase in the HTAB/H2O/DeOH lyotropic system exhibits texture, which is presented in Fig. 6d. This texture consists of the so-called “oily streak” formations. The oily streak formations are the birefringent bands, which form the net on the pseudo-isotropic background. Such
Fig. 3. Typical textures of NC (a) and E (b) mesophases in the HTAB/H2O lyotropic system. Temperature 300.5 K; crossed polarizers; magnification ×100.
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Fig. 7. Planar aligned texture of ND mesophase in the HTAB/H2O/DeOH lyotropic system. Temperature 300.0 K; crossed polarizers; magnification ×100.
Fig. 5. Phase diagram of the HTAB/H2O/DeOH lyotropic system.
type of texture is specific for D mesophase and has been observed by a number of scientists in various liquid crystalline systems [49,51,52, 57–61]. For the control and confirmation of an availability of the rod-like and disc-like micelles in the corresponding regions (regions of E, D, NC and ND mesophases) of the phase diagrams, presented in Figs. 2 and 5, the method of the electrical conductivity anisotropy in the orientational shear flow has been used. As an example, in Figs. 8, 9, and 10 these dependences for the X-, Y- and Z-directions are presented for E, NC, ND and D mesophases. As seen in these figures, the electrical conductivity
anisotropy increases with increasing rotational frequency which claims that an increase in the rotational frequency leads to an increase in the degree of orientational order of anisometric micelles under the shift flow. Besides, from Figs. 8 and 9, it is evident that the electrical conductivity anisotropy in the E and NC mesophases is negative along both Xand Z-directions and while it is positive along the Y-direction. On the other hand for D and ND mesophases the electrical conductivity anisotropy is negative along the X-direction and is positive along both the Yand Z-directions (see Fig. 10). Thus electrical conductivity vs rotational frequency data (Figs. 8, 9, 10) provide information on the availability of lyotropic mesophases containing the rod-like and disc-like (plate-like) micelles in corresponding regions of the phase diagrams (Figs. 2, 5) [20,21,23,25,62,42,53,63]. It is important to note, that the shear flow has not only orientational effect on anisometric micelles of lyotropic mesophases, but can also have deforming effect on these micelles. Such situation was theoretically studied in [20,21,23]. In accordance with theoretical approach [20,21, 23], if the rod-like and disc-like (plate-like) micelles are not deformed by
Fig. 6. Typical textures of NC (a), E (b), ND (c) and D (d) mesophases in the HTAB/H2O/DeOH lyotropic system. Temperature 299.6 K; crossed polarizers; magnification ×100.
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Fig. 9. The electrical conductivity anisotropy vs. rotational frequency for NC mesophase in the HTAB/H2O (a) and HTAB/H2O/DeOH (b) lyotropic systems. Fig. 8. The electrical conductivity anisotropy vs. rotational frequency for E mesophase in the HTAB/H2O (a) and HTAB/H2O/DeOH (b) lyotropic systems.
the flow, the following correlations between the electrical conductivity anisotropy in the X-, Y- and Z-directions, are valid σ X −σ 0 σ Z −σ 0 1 σ Y −σ 0 ¼ ¼ σ 2 σ σ 0
0
ð1Þ
0
length (NC mesophase) and definite diameter (ND mesophase) [64, 66]. The absence of deformation for micelles of ND and NC mesophases under the shear flow is an indicator of the rigid peculiarities of the anisometric micelles with definite sizes [24,40,62,66]. On the other hand, the availability of deformation of micelles in the D and E mesophases is related to the flexibility of spacious micelles [67–72].
for the rod-like micelles and σ Y −σ 0 σ Z −σ 0 1 σ X −σ 0 ¼ ¼ σ 2 σ σ 0 0 0
ð2Þ
for the disc-like (plate-like) micelles. Here σ Xσ−σ 0 , σ Yσ−σ 0 and σ Zσ−σ 0 are the 0 0 0 electrical conductivity anisotropies in the X-, Y- and Z-directions, accordingly. As it is seen from Figs. 8–10, for both HTAB/H2O and HTAB/H2O/ DeOH lyotropic systems the electrical conductivity anisotropy satisfies Eqs. (1) and (2) in the NC and ND mesophases along the X-, Y- and Z-directions while in the E and D mesophases those equations are not satisfied. These facts are indicative of the deformation effect of the shear flow on the anisometric micelles with quasi-indefinite length (E mesophase) and quasi-indefinite diameter (D mesophase). Such a deformation under the shear flow has been reported by several groups for disc-like (plate-like) micelles in the D mesophase [53,64], for the rod-like micelles in the E mesophase [63] and for aqueous mixture of anionic/nonionic surfactant system with anisometric formations [65]. In other respects, it must be stressed that the shear flow does not have deformation effect on the anisometric micelles with definite
4. Conclusion In this work, the phase states and mesomorphic properties of the HTAB/water and the HTAB/water/DeOH lyotropic systems have been investigated and phase diagrams of these systems have been constructed. In the HTAB/water lyotropic system L1 phase, and E and NC mesophases have been found; in the HTAB/water/DeOH lyotropic system L1 phase, and E, NC, ND and D mesophases have been found. The morphologic and structural properties of lyotropic mesophases, taking place in these lyotropic systems, have been studied. Peculiarities of the typical textures of these mesophases have been investigated using the POM and OM techniques. Orientational properties of NC and ND mesophases in the external magnetic field have been investigated. For control and confirmation of an availability of the rod-like and disc-like micelles in the corresponding regions of the phase diagrams, presented in Figs. 2 and 5, the shapes of structural units as the rod-like micelles in E and NC mesophases and as the disc-like (plate-like) micelles in ND and D mesophases were estimated. The method of the electrical conductivity anisotropy in the orientational shear flow has been used.
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Fig. 10. The electrical conductivity anisotropy vs. rotational frequency for ND (a) and D (b) mesophases in the HTAB/H2O/DeOH lyotropic systems.
References [1] S. Friberg, Organized Solutions: Surfactants in Science and Technology, CRC Press, New York, 1992. [2] A.G. Petrov, The Lyotropic State of Matter. Molecular Physics and Living Matter Physics, Gordon & Breach Sci., London — New York, 1999. [3] A.M. Figueiredo Neto, S.R.A. Salinas, The Physics of Lyotropic Liquid Crystals: Phase Transitions and Structural Properties, Oxford University Press, Oxford, 2005. [4] S.K. Wiedmer, M.L. Riekkola, Anal. Chem. 69 (1997) 1577–1584. [5] A. Panatta, V.M. Coiro, F. Mazza, Chem. Phys. Lett. 200 (1992) 130–134. [6] R. Bartolino, M. Meuti, G. Chidichimo, G.A. Ranieri, in: V. Degiorgio, M. Corti (Eds.), Physics of Amphiphiles: Micelles, Vesicles and Microemulsions, North Holland Press, Amsterdam/Oxford/New York/Tokyo, 1985, p. 524. [7] S.T. Hyde, in: K. Holmberg (Ed.), Handbook of Applied Surface and Colloid Chemistry, J. Wiley & Sons, Singapore, 2001, p. 299. [8] G. Montalvo, M. Valiente, E. Rodenas, J. Colloid Interface Sci. 172 (1995) 495–501. [9] G. Montalvo, M. Valiente, E. Rodenas, J. Colloid Interface Sci. 203 (1998) 294–299. [10] D.A. Doshi, A. Gibaud, V. Goletto, M. Lu, H. Gerung, B. Ocko, S.M. Han, C.J. Brinker, J. Am. Chem. Soc. 125 (2003) 11646–11655. [11] M. Angel, H. Hoffmann, M. Löbl, H. Thurn, I. Wunderlich, Progr. Colloid Interface. Sci. 69 (1988) 12–28. [12] M.R. Kuzma, A. Saupe, Handbook of Liquid Crystal, in: P.J. Collings, J.S. Patel (Eds.), Oxford University Press, New York/Oxford, 1997, p. 237. [13] J. Nehring, A. Saupe, J. Chem. Soc. Faraday Trans. 68 (1972) 1–15. [14] J.E. Zimmer, Disclinations in Lamellar Liquid Crystals(Ph.D. Thesis) Pardue University, W.Lafayette, Indiana, 1978.
[15] J.L. White, J.E. Zimmer, Carbon 16 (1978) 469–475. [16] J.E. Zimmer, J.L. White, Adv. Liq. Cryst. 5 (1982) 159–213. [17] J. Lydon, Handbook of Liquid Crystals, in: D. Demus, J. Goodby, G.W. Gray, H.-W. Spiess, V. Vill (Eds.), IIB, Willey-VCH, Weinheim, 1998, p. 981. [18] A. Nesrullajev, M. Tepe, D. Abukay, N. Kazancı, D. Demirhan, F. Büyükkılıç, Appl. Phys. A 71 (2000) 161–167. [19] P. Özden, A. Nesrullajev, Ş. Oktik, Phys. Rev. E. 82 (2010) (061710-1–061710-8). [20] K.G. Götz, K. Heckmann, J. Colloid Sci. 13 (1958) 266–272. [21] K. Heckmann, K.G. Götz, Z. Elektrochem. 62 (1958) 281–288. [22] H. Rehage, Rheologische untersuchungen an viscoelastischen Tensidlösungen(PhD Dissertation) Bayreuth University, Bayreuth, 1982. [23] G. Schwarz, Z. Phys. 145 (1958) 563–584. [24] A. Nesrullajev, Lyotropic Mesomorphism and Electro-Physics of Lyotropic Liquid Crystalline Systems(DSc Dissertation) Institute of Physics, Academy of Sciences, Baku, 1992. [25] K. Heckmann, Discuss. Faraday Soc. 25 (1958) 71–73. [26] V.V. Voytilov, A.A. Trusov, Kolloid J. 67 (1985) 455–461. [27] Y.G. Frolov, Colloid Chemistry, Chemistry Publ., Moscow, 1982. [28] P. Ekwall, Adv. Liq. Cryst. 1 (1975) 1–142. [29] G. Hertel, H. Hoffmann, Progr. Colloid Polym. Sci. 76 (1988) 123–131. [30] G. Hertel, Lyotrope nematische Phasen. Der Zusammenhang zwischen Molekülstruktur und Phasenverhalten(PhD Dissertation) Bayreuth University, Bayreuth, 1989. [31] X. Auvray, C. Petipas, R. Anthore, I. Ricco, A. Lattes, J. Phys. Chem. 93 (1989) 7458–7464. [32] T. Wolf, B. Klauβner, G. Von Bünau, Progr. Colloid Polym. Sci. 83 (1990) 176–180. [33] A.B. Cortés, M. Valiente, E. Rodenas, Langmuir 15 (1999) 6658-6603. [34] O. Canãdas, M. Valiente, E. Rodenas, J. Colloid Interface Sci. 203 (1998) 294–298. [35] K. Hiltrop, in: H.-S. Kitzerow, C. Bahr (Eds.), Chirality in Liquid Crystals, Springer, Berlin, 2001, p. 447. [36] E. Nativ-Roth, O. Regev, R. Yerushalmi-Rozen, Chem. Commun. (2008) 2037–2039. [37] R. Xsu, W. Pank, J. Yu, Q. Huo, J. Chen, Chemistry of Zeolites and Related Porous Materials: Synthesis and Structure, John Wiley & Sons, Singapore, 2007. [38] A.M. Figueiredo Neto, L. Amaral, Mol. Cryst. Liq. Cryst. 95 (1983) 129–141. [39] Y. Hendrikx, J. Charvolin, M. Rawiso, L. Liebert, M.S. Holmes, J. Phys. Chem. 87 (1983) 3991–3999. [40] A.S. Sonin, Usp. Fiziol. Nauk 153 (1987) 273–310; Sov. Phys. Usp. 30 (1987) 875–912. [41] A. Nesrullajev, N. Kazancı, T. Yıldız, Mater. Chem. Phys. 80 (2003) 710–713. [42] A. Nesrullajev, Mater. Chem. Phys. 123 (2010) 546–550. [43] E.V. Generalova, E.L. Kitaeva, A.N. Nesrullajev, A.S. Sonin, Colloid J. 52 (1990) 958–960. [44] H. Hoffmann, G. Oetter, B. Schwandner, Progr. Colloid Polym. Sci. 73 (1987) 95–106. [45] A. Nesrullajev, S. Oktik, Cryst. Res. Technol. 42 (2007) 44–49. [46] A.R. Sampaio, A.J. Palangana, R.C. Visconini, Mol. Cryst. Liq. Cryst. 408 (2004) 45–51. [47] http://wapedia.mobi/en/Hexagonal_phase. [48] A. Nesrullajev, M. Tepe, N. Kazancı, H.M. Çakmak, D. Abukay, Mater. Chem. Phys. 65 (2000) 125–129. [49] A. Nesrullajev, M. Okcan, N. Kazanci, J. Mol. Liq. 108 (2003) 313–332. [50] S.T. Hyde, Handbook of Applied Surface and Colloid Chemistry, in: K. Holmberg (Ed.), John Wiley & Sons, New York, 2001, p. 299. [51] S.K. Ghosh, Influence of Strongly Bound Counterions on the Phase Behavior of Ionic Amphiphiles(PhD Thesis) Raman Research Institute, Bangalore, 2007. [52] R. Krishnaswamy, S.K. Ghosh, S. Lakshmanan, V.A. Raghunathan, A.K. Sood, Langmuir 21 (2005) 10439–10443. [53] A. Nesrullajev, J. Mol. Liq. 187 (2013) 337–342. [54] G. Burducea, Rom. Rep. Phys. 56 (2004) 66–86. [55] A. Nesrullajev, Lyotropic Liquid Crystals: amphiphilic Systems, Ege University Press, Izmir, 2007. [56] G. Bartusch, H.-G. Dörfler, H. Hoffmann, Progr. Colloid Polym. Sci. 89 (1992) 307–314. [57] J.C. Wittmann, B. Lotz, F. Candau, A.J. Kovacs, J. Polym. Sci. 20 (1982) 1341–1344. [58] H.-D. Dörfler, A. Göpfert, Colloid Polym. Sci. 278 (2000) 1085–1096. [59] H.D. Dörfler, Adv. Colloid Interface Sci. 98 (2002) 285–340. [60] S. Ujiie, Y. Yano, Chem. Commun. (2000) 79–80. [61] D. Constantin, P. Davidson, C. Chaneac, Langmuir 26 (2010) 4586–4589. [62] V.N. Tsvetkov, Hard-Chain Polymer Molecules, Science Publ., Moscow, 1986. [63] A. Nesrullajev, Tenside Surfactants Deterg. 47 (2010) 179–183. [64] A. Nesrullajev, Kolloid J. 54 (1992) 125–132. [65] J. Crawshaw, G. Meeten, Rheol. Acta 46 (2006) 183–193. [66] G.B. Thurston, P. Munk, J. Chem. Phys. 52 (1970) 2359–2365. [67] S. Ozeki, S. Ikeda, Colloid Polym. Sci. 262 (1984) 409–417. [68] A. Flamberg, R. Pecora, J. Chem. Phys. 88 (1984) 3026–3033. [69] W. Van De Sande, A. Persoons, J. Phys. Chem. 89 (1985) 404–409. [70] T. Imae, T. Kamiya, S. Ikeda, J. Colloid Interface Sci. 108 (1985) 215–225. [71] T. Imae, S. Ikeda, Colloid Polym. Sci. 265 (1987) 1090–1098. [72] M. Lukaschek, D.A. Grabowski, C. Schmidt, Langmuir 11 (1995) 3590–3594.