Induced smectic phase in binary mixtures of twist-bend nematogens

• Anamarija Knežević,
• Irena Dokli,
• Marin Sapunar,
• Suzana Šegota,
• Ute Baumeister and
• Andreja Lesac

Beilstein J. Nanotechnol. 2018, 9, 1297–1307, doi:10.3762/bjnano.9.122

• ]. Apart from shifting the phase transition temperatures in the mixtures of two LC compounds, the formation of a new mesophase is also an interesting phenomenon. The first induced mesophase was discovered in binary rod-like nematic liquid crystal mixtures of N-(p-methoxybenzylidene)-p-n-butylaniline (MBBA

• ]. The N–NTB phase transition has been confirmed observing characteristic blocky texture from which polygon and rope textures developed. The X-ray diffraction (XRD) measurements in both nematic phases show that the d value for the maxima of the inner scattering in the nematic phase is at about 1.4 nm for

• the Figure 4e. Most recently Clark’s group indicated that the helix pitch (pH) of CB7CB experimentally measured by resonant soft X-ray scattering (RSoXS) appears to be controlled by the molecular bend and can be approximated with 2πRmol of a single all-trans molecule near the N–NTB phase transition

Formation and development of nanometer-sized cybotactic clusters in bent-core nematic liquid crystalline compounds

• Yuri P. Panarin,
• Sithara P. Sreenilayam,
• Jagdish K. Vij,
• Anne Lehmann and
• Carsten Tschierske

Beilstein J. Nanotechnol. 2018, 9, 1288–1296, doi:10.3762/bjnano.9.121

• closer to the nematic–smectic phase transition temperature by de Vries [34]. The XRD investigations of BCN66 in the nematic temperature range show two diffuse X-ray scatterings, wide-angle and small-angle. The small-angle scattering corresponds to the short-range periodicity of a group of molecules in

Proximity effect in a two-dimensional electron gas coupled to a thin superconducting layer

• Christopher Reeg,
• Daniel Loss and
• Jelena Klinovaja

Beilstein J. Nanotechnol. 2018, 9, 1263–1271, doi:10.3762/bjnano.9.118

• topological phase transition is determined by the interfacial tunneling energy. In order to induce a topological phase more reliably, a much weaker coupling between a 2DEG and a bulk superconductor (such that γ ≤ Δ) should be sought. We also note that this result applies to the 1D model considered in [48] as

Inverse proximity effect in semiconductor Majorana nanowires

• Alexander A. Kopasov,
• Ivan M. Khaymovich and
• Alexander S. Mel'nikov

Beilstein J. Nanotechnol. 2018, 9, 1184–1193, doi:10.3762/bjnano.9.109

• find, of course, only the critical temperatures corresponding to the second-order phase transitions. Changing the period of the gap modulation of the FFLO-type we also find only the temperatures corresponding to the second-order phase transition. The physical picture can become more complicated if one

P3HT:PCBM blend films phase diagram on the base of variable-temperature spectroscopic ellipsometry

• Barbara Hajduk,
• Henryk Bednarski,
• Bożena Jarząbek,
• Henryk Janeczek and
• Paweł Nitschke

Beilstein J. Nanotechnol. 2018, 9, 1108–1115, doi:10.3762/bjnano.9.102

• temperature changes. Characteristic temperatures determined from the slope changes of the Δ(T) plot appeared to be very good guess values for the phase transition temperatures. Keywords: non-linear optics; organic semiconductors; spectroscopic ellipsometry; theoretical modeling; thin films; Introduction The

• power conversion efficiency of OPV devices can be also optimized using thermal treatment related to the phase transition temperature. For instance, Pearson et al. [22] demonstrated that the most efficient devices were heated above the upper apparent glass transition temperature (Tg) of P3HT:PCBM blends

• ], but also conjugated polymers such as polyfluorenes [36][37][38], quinoxaline and carbazole-based copolymers [39][40] and conjugated polymer:fullerene blends [23][41][42]. Frequently, the identification of the phase transition temperatures can be performed using the raw ellipsometric data [28][41][43

Synthesis and characterization of two new TiO₂-containing benzothiazole-based imine composites for organic device applications

• Anna Różycka,
• Agnieszka Iwan,
• Krzysztof Artur Bogdanowicz,
• Michal Filapek,
• Natalia Górska,
• Damian Pociecha,
• Marek Malinowski,
• Patryk Fryń,
• Agnieszka Hreniak,
• Jakub Rysz,
• Paweł Dąbczyński and
• Monika Marzec

Beilstein J. Nanotechnol. 2018, 9, 721–739, doi:10.3762/bjnano.9.67

• interaction. Also the temperature of the phase transition was slightly affected with the increase of TiO2 concentration in imine-based composites. The changes observed in the Fourier transform middle-infrared absorption (FT-MIR) spectra confirmed the significant influence of TiO2 on structural properties of

• SP1 and SP2 are shown in Figure 5. Asymmetrical imine SP2 exhibited a higher melting point (mp 78.39 °C) than symmetrical SP1 (mp 66.31 °C). DSC curves of SP2 exhibited two peaks (see Figure 6), where the most intense one is attributed to the phase transition into isotropic liquid. However, the less

• of TiO2. DSC curves (Figure 6) for SP2:TiO2 mixtures with different concentrations of TiO2 were measured during heating and cooling at a rate of 10 °C/min. The phase transition temperatures changed slightly with increase in the concentration of TiO2 (see Table 2). It also turned out that titanium

Combined pulsed laser deposition and non-contact atomic force microscopy system for studies of insulator metal oxide thin films

• Daiki Katsube,
• Hayato Yamashita,
• Satoshi Abo and
• Masayuki Abe

Beilstein J. Nanotechnol. 2018, 9, 686–692, doi:10.3762/bjnano.9.63

• TiO2(001) is said to undergo a structural change to rutile TiO2(001) at around 750 °C, the XRD pattern showed that the anatase phase remained in this case. This is due to the lattice constant of the substrate. Considering that a phase transition from anatase to rutile may occur if the temperature is

Periodic structures on liquid-phase smectic A, nematic and isotropic free surfaces

• Anna N. Bagdinova,
• Evgeny I. Demikhov,
• Nataliya G. Borisenko,
• Sergei M. Tolokonnikov,
• Gennadii V. Mishakov and
• Andrei V. Sharkov

Beilstein J. Nanotechnol. 2018, 9, 342–352, doi:10.3762/bjnano.9.34

• picture is completely changed in this case and we see the formation of periodic stripes perpendicular to the direction of motion of the tip. Figure 6 shows the formation of the periodic stripe pattern in the SmA phase after the phase transition N–SmA. We observe a periodic structure in the SNOM image with

• temperature (a) and its cross-section (b). Periodic structure formation after Cry–SmA phase transition at room temperature. Topographical AFM (a) and SNOM (b) SmA droplet edge images on Si substrate, AFM and SNOM cross-sections (c) and (d). Periodic SmA structure formation at room temperature after cooling

Design of polar self-assembling lactic acid derivatives possessing submicrometre helical pitch

• Alexej Bubnov,
• Cyril Vacek,
• Michał Czerwiński,
• Terezia Vojtylová,
• Wiktor Piecek and
• Věra Hamplová

Beilstein J. Nanotechnol. 2018, 9, 333–341, doi:10.3762/bjnano.9.33

• SmC* (up to 90 K) phases observed on cooling from the isotropic phase (Iso). The polar phases are observed down to room temperatures before the onset of the crystal (Cr) phase. The temperature of the Iso–SmA* phase transition slightly increases with the length of the chain attached to the non-chiral

• component of the tilt angle should be taken into account only in the vicinity of the SmA*–SmC* phase transition. At the SmA*–SmC* phase transition, the increase of Ps and θs values of KL n/m compounds is continuous (see Figure 2ab), which can be related to the second order phase transition. Similar

• ]. The soft mode behaviour, which is related to fluctuations of molecules (arranged in smectic layers) in the direction of the tilt angle θs, has been detected in the SmA* phase close to the SmA*–SmC* phase transition. A comprehensive discussion on the specific behaviour of all the detected modes

Liquid-crystalline nanoarchitectures for tissue engineering

• Baeckkyoung Sung and
• Min-Ho Kim

Beilstein J. Nanotechnol. 2018, 9, 205–215, doi:10.3762/bjnano.9.22

• example of LC phases of biocolloids, especially focused on the B-form of double-stranded DNA (dsDNA). Here the rod-like fragments (50 nm in length) of dsDNA undergo a phase transition in dependence on the rod concentration, dissolved in the 0.25 M ammonium acetate buffer. The polymorphic LC phases and

• I, the major fibrous protein component in the extracellular matrix (ECM), has been shown to exhibit an isotropic-to-cholesteric phase transition (via the precholesteric phase) as the collagen concentration increases in acidic environments [43][44]. For example, solutions of type-I collagen triple

• coherence within local microenvironments in vivo, similar to our native tissue function [128]. Lyotropic liquid-crystalline phase transition of a dispersion of rod-like particles as a function of rod volume fraction (i.e., rod concentration). A biopolymer (such as dsDNA, collagen, chitin and cellulose) or a

Bombyx mori silk/titania/gold hybrid materials for photocatalytic water splitting: combining renewable raw materials with clean fuels

• Stefanie Krüger,
• Michael Schwarze,
• Otto Baumann,
• Christina Günter,
• Michael Bruns,
• Christian Kübel,
• Dorothée Vinga Szabó,
• Rafael Meinusch,
• Verónica de Zea Bermudez and
• Andreas Taubert

Beilstein J. Nanotechnol. 2018, 9, 187–204, doi:10.3762/bjnano.9.21

• photocatalytic water splitting (see below) the wet samples were used. To ensure that there is no drying-induced phase transition in the hybrid materials, XRD was also done on a wet sample (Figure S5b, Supporting Information File 1). Clearly, the wet samples produce a higher X-ray background due to large amounts

Dielectric properties of a bisimidazolium salt with dodecyl sulfate anion doped with carbon nanotubes

• Doina Manaila Maximean,
• Viorel Cîrcu and
• Constantin Paul Ganea

Beilstein J. Nanotechnol. 2018, 9, 164–174, doi:10.3762/bjnano.9.19

• observations clearly indicated that the two transformations are well separated. The following cooling run shows the Iso-SmA phase transition at 321.15 K followed by a second transition at 285.15 K, which was assigned to a transition from the LC phase to a different crystalline phase (Cr′). This second Cr

• studies while the corresponding phase transition enthalpies were obtained by DSC. The ILC was doped with CNT in concentration of 0.05% w/w and 0.5% w/w. The dielectric spectra were recorded in the frequency range from 10−1 to 107 Hz. The dependence of the dielectric constant and electric energy loss on

Electrical properties of a liquid crystal dispersed in an electrospun cellulose acetate network

• Doina Manaila Maximean,
• Octavian Danila,
• Pedro L. Almeida and
• Constantin Paul Ganea

Beilstein J. Nanotechnol. 2018, 9, 155–163, doi:10.3762/bjnano.9.18

• cell after the LC was introduced. The changes of slope may indicate phase transitions. Thus, we can suppose that CA without LC might have a phase transition at T = 315 K. Similarly, the sample CA/E7 might have a phase transition at about 333 K. The verification of this supposition is based on the

• , after the nematic-to-isotropic phase transition. Impedance spectroscopy The impedance, Z, and the quality factor (dielectric loss tangent), θ, were measured using impedance spectroscopy [41][42][43]. Based on the obtained data, the real (active) impedance component, Z′, and the imaginary (reactive

• . Dielectric spectroscopy (DS) and impedance measurements were performed on the electro-optic cells before and after filling in the LC. Also, the dependency of the dielectric constant and electric energy loss on frequency and temperature was studied. The nematic–isotropic phase transition temperature of E7 and

Nematic topological defects positionally controlled by geometry and external fields

• Pavlo Kurioz,
• Marko Kralj,
• Bryce S. Murray,
• Charles Rosenblatt and
• Samo Kralj

Beilstein J. Nanotechnol. 2018, 9, 109–118, doi:10.3762/bjnano.9.13

• ], we introduce the reduced temperature where T** is the nematic superheating temperature. In this scaling the bulk phase transition temperature TIN corresponds to and the bulk degree of uniaxial ordering minimizing Equation 5 can be expressed as The materials properties of the LC are reflected in

Magnetic field induced orientational transitions in liquid crystals doped with carbon nanotubes

• Danil A. Petrov,
• Pavel K. Skokov and
• Alexander N. Zakhlevnykh

Beilstein J. Nanotechnol. 2017, 8, 2807–2817, doi:10.3762/bjnano.8.280

• (ferromagnetic) particles was proposed in [45][46]. This approach is based on the mean-field theory, and allows for an investigation of the influence of temperature and magnetic field on a suspension, including the phase transition from the ordered phase into the nematic or paranematic state. We plan to propose

Thermo- and electro-optical properties of photonic liquid crystal fibers doped with gold nanoparticles

• Agata Siarkowska,
• Miłosz Chychłowski,
• Daniel Budaszewski,
• Bartłomiej Jankiewicz,
• Bartosz Bartosewicz and
• Tomasz R. Woliński

Beilstein J. Nanotechnol. 2017, 8, 2790–2801, doi:10.3762/bjnano.8.278

• transition temperature, thus improving the thermo- and electro-optical properties of the PLCF. Keywords: fiber optics; gold nanoparticle; liquid crystal; phase transition temperature; photonic crystal fiber; Introduction Since their discovery in 1888, liquid crystals (LCs) have attracted nonstop research

• nematic–isotropic phase transition temperature [21][22], but with a specific surface coating, the effect can be reversed [23]. The presence of Au NPs in an LC has proven to influence the response time and lower the threshold voltage [24][25][26][27][28]. In this paper we compare four different

• knowledge there are no published reports considering a PLCF with Au-doped LCs. Experimental The experiments were divided into two parts: the investigation of the temperature influence on Au NP-doped LCs (with a focus on the nematic–isotropic (N–I) phase transition temperature) and the influence of an

CdSe nanorod/TiO₂ nanoparticle heterojunctions with enhanced solar- and visible-light photocatalytic activity

• Fakher Laatar,
• Hatem Moussa,
• Halima Alem,
• Lavinia Balan,
• Emilien Girot,
• Ghouti Medjahdi,
• Hatem Ezzaouia and
• Raphaël Schneider

Beilstein J. Nanotechnol. 2017, 8, 2741–2752, doi:10.3762/bjnano.8.273

• located at 2θ = 27.55, 36.23, 41.34 and 56.72° belong to rutile TiO2 (JCPDS No 21-1276) (Figure 2b). The anatase and rutile phases of TiO2 exhibit a higher catalytic activity than the brookite phase [44]. The anatase/rutile ratio was not affected by the heating at 300 °C (the phase transition occurs at

Ferrocholesteric–ferronematic transitions induced by shear flow and magnetic field

• Dmitriy V. Makarov,
• Alexander A. Novikov and
• Alexander N. Zakhlevnykh

Beilstein J. Nanotechnol. 2017, 8, 2552–2561, doi:10.3762/bjnano.8.255

• shown below in Figure 2–Figure 5. The areas that are bounded in these diagrams by the curves and the coordinate axes correspond to the ferrocholesteric phase; the external areas correspond to the ferronematic phase. Figure 2 represents a diagram of the ferrocholesteric–ferronematic phase transition in

• ., with an increase in the concentration of the magnetic impurity. Figure 3 represents a diagram of the ferrocholesteric–ferronematic phase transition in the plane u–φH for h = 1 and ξ = 0.1 for different values of the reactive parameter, including the so-called non-flow-aligning LCs (Equation 1) with λ

• structure with λ < 1. In Figure 3 we see that as λ decreases, the critical value of uc decreases and weakly depends on the orientation of the external magnetic field. Figure 4 and Figure 5 represent the diagrams of the ferrocholesteric–ferronematic phase transition in the plane u–h for the magnetic field

Nanoprofilometry study of focal conic domain structures in a liquid crystalline free surface

• Anna N. Bagdinova,
• Evgeny I. Demikhov,
• Nataliya G. Borisenko and
• Sergei M. Tolokonnikov

Beilstein J. Nanotechnol. 2017, 8, 2544–2551, doi:10.3762/bjnano.8.254

• smectic phase become smaller than at 32 °C and disappear after the phase transition of smectic-A–nematic. The dynamics of the crater formation is shown on Figure 4. In this experiment, a small droplet of the 8CB material was placed on the LC display substrate with a sharp tip. Then the substance was

• heated to the temperature of the isotropic liquid phase 43 °С on a heating stage. Then the heating table was turned off and the substance was cooled to room temperature. At a temperature of 32 °С, the phase transition to the smectic phase occurred and the crater formation began. The temperature was

• no structures and was found to be isotropic in both cases. The FCDs are formed just below the phase transition SmA–nematic. It is important to underline that the FCDs are a result of the correlation of the director field orientations on both surfaces. The interaction between surfaces due to the conic

Alternating current magnetic susceptibility of a ferronematic

• Natália Tomašovičová,
• Jozef Kováč,
• Veronika Gdovinová,
• Nándor Éber,
• Tibor Tóth-Katona,
• Jan Jadżyn and
• Peter Kopčanský

Beilstein J. Nanotechnol. 2017, 8, 2515–2520, doi:10.3762/bjnano.8.251

• crystal and the magnetic field. Experiments have proved that MNPs can alter the threshold fields for structural (e.g., Fréedericksz) transitions [9][10][11]; unexpected magneto-optical [12][13] and magneto-dielectric effects [14] have been found and shifts in the isotropic-to-nematic phase-transition

• -nematic phase transition on cooling (unless the bias field is applied again in the isotropic phase). A phenomenological explanation of the experimental results related this behavior to defect-mediated aggregation and magnetic-field-assisted disaggregation of MNPs [27]. In principle, the effect can provide

• particles are superparamagnetic. The temperature of the phase transition of the samples was detected by independent capacitance measurements in a capacitor made of ITO-coated glass electrodes (AWAT). The capacitor with an electrode area of approximately 5 mm × 5 mm was placed into a regulated thermostat

Stick–slip boundary friction mode as a second-order phase transition with an inhomogeneous distribution of elastic stress in the contact area

• Iakov A. Lyashenko,
• Vadym N. Borysiuk and
• Valentin L. Popov

Beilstein J. Nanotechnol. 2017, 8, 1889–1896, doi:10.3762/bjnano.8.189

• /bjnano.8.189 Abstract This article presents an investigation of the dynamical contact between two atomically flat surfaces separated by an ultrathin lubricant film. Using a thermodynamic approach we describe the second-order phase transition between two structural states of the lubricant which leads to

• . The boundary friction mode can be described within the framework of several theoretical models [6][7][8][9][10][11][12] where lubricant melting is described either as a first-order [8][9], or a second-order [10][11] phase transition. It is worth mentioning that in three-dimensional systems, melting

• always appears as a first-order phase transition [13], while in the systems with confined lubricant, second-order phase transitions were observed in both numerical [14][15][16] and theoretical [10] studies. Moreover, recent experimental investigations [5] have shown that melting as a first-order phase

Formation of ferromagnetic molecular thin films from blends by annealing

• Peter Robaschik,
• Ye Ma,
• Salahud Din and
• Sandrine Heutz

Beilstein J. Nanotechnol. 2017, 8, 1469–1475, doi:10.3762/bjnano.8.146

• of the nearest-neighbouring MnPc molecule. The magnetic interaction has been attributed to superexchange [11][12][13], although more recent results highlight that indirect exchange also contributes to the mechanism [14]. Here we develop a strategy to lower the phase-transition temperature of MnPc by

• 60 °C by blending the MnPc film with TCNQ in the starting films deposited at room temperature. Optical microscopy and X-ray diffraction (XRD) are used to identify the phase transition by investigation of the surface morphology and the structure of the films, while FTIR spectroscopy provides

• , respectively [17][20], assuming that MnPc is isostructural with CuPc. This represents an intermediate case with a partial transformation from α- to β-phase as shown earlier for metal-free phthalocyanine thin films where Yim et al. proposed a phase-transition mechanism that involves tilting of the α-phase

Comprehensive Raman study of epitaxial silicene-related phases on Ag(111)

• Dmytro Solonenko,
• Ovidiu D. Gordan,
• Guy Le Lay,
• Dietrich R. T. Zahn and
• Patrick Vogt

Beilstein J. Nanotechnol. 2017, 8, 1357–1365, doi:10.3762/bjnano.8.137

• on Ag(111), where a 2D-to-3D phase transition takes place. Reports of an almost perfectly ordered 2D Si layer formed on Ag(111) at almost 400 °C may be related to problems with temperature determination [15]. Si deposition at temperatures between 220 and 290 °C All the results presented so far show

Fabrication of hierarchically porous TiO₂ nanofibers by microemulsion electrospinning and their application as anode material for lithium-ion batteries

• Jin Zhang,
• Yibing Cai,
• Xuebin Hou,
• Xiaofei Song,
• Pengfei Lv,
• Huimin Zhou and
• Qufu Wei

Beilstein J. Nanotechnol. 2017, 8, 1297–1306, doi:10.3762/bjnano.8.131

• 0.1 mV/s are shown in Figure S1 (Supporting Information File 1). Sample A2 has obvious reduction and oxidation peaks at about 1.49 and 2.33 V. The reduction peak corresponded to the intercalation of Li+ into interstitial octahedral sites of anatase TiO2 via a phase transition from tetragonal anatase

• curves at around 1.93 V, which were due to the phase transition between tetragonal anatase and orthorhombic Li0.5TiO2 [38]. The initial discharge capacities of sample A2, sample B2 and sample C2 were 634.72, 583.44 and 522.65 mAh·g−1, and the corresponding charge capacities were 390.42, 367.85 and 279.82

Vapor-phase-synthesized fluoroacrylate polymer thin films: thermal stability and structural properties

• Paul Christian and
• Anna Maria Coclite

Beilstein J. Nanotechnol. 2017, 8, 933–942, doi:10.3762/bjnano.8.95

• cycles (as described in the Experimental section), a reversible behavior is recorded. Figure 6a shows a typical measurement for a PFDA homopolymer for a heating and a cooling run. The data features most notably a first-order phase transition, with the onsets at 73 and 71 °C, determined by linear fits to