Lyotropic Liquid Crystalline Properties Research Articles

Synthesis and characterization of grafted graphene oxide materials with lyotropic liquid crystalline properties detected by NMR spectroscopy

Grafted derivatives of graphene oxide (GO), namely N-vinyl-2-pyrrolidone grafted-GO (GO-g-NVP) and oleic acid grafted-GO (GO-g-OLA) were prepared by heating GO in the presence of the corresponding vinyl monomers and the AIBN radical initiator. The lyotropic mesogenic behavior of GO-g-NVP and GO-g-OLA in DMSO‑d6 was proved by deuterium NMR spectroscopy, showing these materials could be used as alignment media for obtaining NMR anisotropic parameters in organic solvent.

Review in The Biological applications of glycolipids liquid crystals

Glycolipids are essential components in the most living systems cells. They can playing different roles and activities inside and outside the bilayer membrane that surrounding the cells. They consider as biosurfactants because their structure that is contain polar head groups and the other accompany part the non-polar long-chain alcohols. In this context, these bio-surfactants can found in different phases in lyotropic liquid crystalline properties and therefore, many actions that related to these phases can offer a wide-range of roles like antibacterial, antifungal anti-cancer and antenna for most recognition of the materials that affected the cell membranes.

Understanding mesophase pitch from a lyotropic liquid crystalline perspective

This review explores recent research regarding mesophase pitch (MP). Spinnable mesophase pitch (SMP) was used as a model pitch for MP in all experiments. We explain some phenomenological results of the lyotropic liquid crystalline properties of the SMP, which show that the MP behaves as a typical lyotropic liquid crystal. The mesogenic and solvent components of SMP are defined. We define the threshold concentration (TC) as the minimum amount of mesogenic component necessary for SMP to achieve 100 vol% anisotropy. We also report the TCs of various SMPs and discuss the effects of the solvent component. Concerning the identity of the mesogenic component, we discuss quantitative correlations between the size of the layered molecular stacking units and the anisotropic content of the SMP. Research has shown that a layered molecular stacking unit larger than a specific size corresponds to the mesogenic component of the MP. We discuss a novel method for the manufacture of SMPs using our understanding of MP as a lyotropic liquid crystal, which comprises thermal mixing of optimal amounts of the mesogenic and solvent components that were prepared separately under different conditions. This method enables the properties of each component to be optimized without involving a costly hydrogenation process. Finally, we discuss how this approach can be used to increase SMP yield by modifying the contents of the anisotropic mesogenic and solvent components.

Lyotropic Liquid Crystalline Property and Organized Structure in High Proton-Conductive Sulfonated Semialicyclic Oligoimide Thin Films.

Fully aromatic sulfonated polyimides with a rigid backbone can form lamellar structures under humidified conditions, thereby facilitating the transmission of protons in ionomers. Herein, we synthesized a new sulfonated semialicyclic oligoimide composed of 1,2,3,4-cyclopentanetetracarboxylic dianhydride (CPDA) and 3,3'-bis-(sulfopropoxy)-4,4'-diaminobiphenyl to investigate the influence of molecular organized structure and proton conductivity with lower molecular weight. The weight-average molecular weight (M w) determined by gel permeation chromatography was 9300. Humidity-controlled grazing incidence X-ray scattering revealed that one scattering was observed in the out-of-plane direction and showed that the scattering position shifted to a lower angle as the humidity increased. A loosely packed lamellar structure was formed by lyotropic liquid crystalline properties. Although the ch-pack aggregation of the present oligomer was reduced by substitution to the semialicyclic CPDA from the aromatic backbone, the formation of a distinct organized structure in the oligomeric form was observed because of the linear conformational backbone. This report is the first-time observation of the lamellar structure in such a low-molecular-weight oligoimide thin film. The thin film exhibited a high conductivity of 0.2 (±0.01) S cm-1 under 298 K and 95% relative humidity, which is the highest value compared to the other reported sulfonated polyimide thin films with comparable molecular weight.

Bentonite Clay Liquid Crystals for High-Performance Supercapacitors

As the human population increases, there is invariably excessive demand for energy sources, thus making it a fundamental need. The basic use of supercapacitors is the storage of energy. But self-discharge is caused when no external power or internal battery is charging them. This clearly reduces their efficiency. It has been found that self-discharge can be reduced to a great extent by employing liquid crystals (LC). But the effect of LC in enhancing the supercapacitor properties has not been discussed. So here, the naturally available bentonite clay is analyzed for its lyotropic liquid crystalline (LLC) properties. It showed liquid crystalline properties at 0.055 g/cm3 in 0.2 M Na2SO4 solvent. It is characterized by a polarised optical microscope (POM). These LCs are added as an additive electrolyte to the supercapacitors. The electrode materials used for supercapacitors are a composite of activated carbon and polyaniline. When compared, the supercapacitor properties were enhanced with a decrease in IR drop in supercapacitors containing bentonite lyotropic liquid crystal, producing a specific capacitance of 237.5 F/g at a current density of 0.5 mA/cm3. The electrochemical behavior of the supercapacitors is determined by cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge-discharge cycling techniques.Graphical

Hierarchical lyotropic liquid crystalline behaviors of supramolecular polymers influenced by alkyl chain branching

The peripheral chain branching in monomeric structures influences the hierarchical supramolecular assembly and lyotropic liquid crystalline properties.

Hydroxyapatite Nanoparticle Mesogens: Morphogenesis of pH-Sensitive Macromolecular Liquid Crystals

Numerous living structural materials display self-assembly of building blocks. Biological molecular networks exhibit lyotropic liquid crystalline properties that can support non-equilibrium pathway...

Lyotropic Liquid Crystals from Colloidal Suspensions of Graphene Oxide

Lyotropic liquid crystals from colloidal particles have been known for more than a century, but have attracted a revived interest over the last few years. This is due to the developments in nanoscience and nanotechnology, where the liquid crystal order can be exploited to orient and reorient the anisotropic colloids, thus enabling, increasing and switching the preferential properties of the nanoparticles. In particular, carbon-based colloids like carbon nanotubes and graphene/graphene–oxide have increasingly been studied with respect to their lyotropic liquid crystalline properties over the recent years. We critically review aspects of lyotropic graphene oxide liquid crystal with respect to properties and behavior which seem to be generally established, but also discuss those effects that are largely unfamiliar so far, or as of yet of controversial experimental or theoretical outcome.

Effects of Side Chain Branch Point on Self Assembly, Structure, and Electronic Properties of High Mobility Semiconducting Polymers

Semiconducting polymers exhibiting lyotropic liquid-crystalline (LC) mesophases allow for precise control over crystallinity and crystallite orientation using scalable equilibrium processing techniques. The ability to control morphologies from molecular to macroscopic scales is desirable for optimizing polymer electronic devices such as field-effect transistors. LC mesophases can form in semiconducting polymers with branched side chains, but steric repulsion from the side chain structure increases π-stacking distances. This change in unit cell negatively impacts electronic transport, negating any improvements gained by achieving more favorable mesostructures. Herein, we show that the π-stacking distance in cyclopentadithiophene-benzothiadiazole donor–acceptor copolymers is successively shortened by moving the branch point further away from the conjugated backbone. These materials retain their favorable LC properties, and the change in unit cell is accompanied by a monotonic increase in charge carrier mobi...

Redox-controlled reversible micelles transition and lyotropic liquid-crystalline behavior of novel polymerizable ferrocenyl surfactants

A novel photopolymerizable surfactant with ferrocenyl group, (11-ferrocenylundecyl) (ethyl methacrylate) dimethylammonium bromide (I+), was synthesized through the reaction of 11-bromoundecyl ferrocene and N,N-(dimethylamino) ethyl methacrylate. Based on the results of voltammetric cycle, the small potential difference ΔE was 72 mV, which indicates that the I+ has good redox reversibility. The critical micellar concentration (CMC) values were about 0.5 and 22.7 mM for I+ in the reduction (CMCred) and oxidation state (CMCox) and it could aggregate and disaggregate by using redox reaction and photopolymerization when its concentrations was between their CMCred and CMCox values. The lyotropic liquid-crystalline properties of I+ in water were investigated by X-ray diffraction (XRD) and plarized optical microscope (POM). The results indicate when the concentration of the I+ solution over 40 wt %, an ordered lamellar liquid crystal structure was formed. With increasing concentration, the nanoscopic long-range order improved. Moreover, the lyotropic liquid-crystalline properties of I+ could also be controlled by using redox reaction and photopolymerization. In a word, the novel polymerizable ferrocenyl surfactants are good environmental responsive materials and can potentially act as the drug carrier and the scavenger for removing dissolved organic impurities in water.

Lyotropic Liquid-crystalline Pseudo-polymer Particles with an Iron Oxide Monodispersed Core Controlled in Size and Shapes in Ionic Liquids

Spindle- and disk-shaped pseudo-poly(methyl methacrylate) particles obtained by the surface-initiated atom transfer radical polymerization on α-Fe2O3 or Fe3O4 monodispersed fine particles exhibited lyotropic liquid-crystalline behavior in ionic liquids for a wide range of the mixing ratio. Effects of the size and shape of the particles on the lyotropic liquid-crystalline properties and the nanolevel self-organized structures have also been investigated.

Synthesis and characterization of new aramids based on o-(m-triphenyl)-terephthaloyl chloride and m-(m-triphenyl)-isophthaloyl chloride

Two monomers o-(m-triphenyl)-terephthaloyl chloride (TPH1-COCl) and m-(m-triphenyl)- isophthaloyl chloride (TPH2-COCl) with bulky pendant groups were prepared, and they were polymerized with p-phenylenediamine (PPD) or copolymerized with PPD and terephthaloyl chloride (TPC) to prepare aromatic polyamides which were named TPH1 polymer and TPH2 polymer, respectively. The structures of the monomers with bulky pendant groups and the polymers were characterized by 1H NMR and gel permeation chromatography. The resulting polymers are soluble in some organic solvents such as N-methyl-2-pyrrolidone. However, the solubility of the two series of polymers was different due to the different structures of the two monomers, and it is affected by the feeding ratio of the monomers. Both kinds of polymers have good thermal stabilities with 5% weight loss temperatures close to 500 °C. And glass transitions of some TPH2 polymers were observed. Most of these polyamides show lyotropic liquid crystalline (LLC) behaviors as evidenced by polarized light microscopy results. And the LLC properties are influenced by the structures, molecular weights, and concentrations of the polymers.

A Comprehensive Study on Lyotropic Liquid-Crystalline Behavior of an Amphiphile in 20 Kinds of Amino Acid Ionic Liquids.

We examined the self-organization behavior of a designed amphiphilic molecule in 20 kinds of amino acid ionic liquids composed of 1-butyl-3-methylimidazolium cation and natural amino acid anion ([C4mim][AA]). Addition of [C4mim][AA], regardless of their anion species, to the amphiphile provided homogeneous mixtures showing lyotropic liquid-crystalline (LC) behavior. Upon increasing the component ratio of [C4mim][AA] in the mixtures, a successive change of the mesophase patterns from inverted hexagonal columnar, in some case via bicontinuous cubic, to layered phases was observed. By examining the LC properties at various temperatures and component ratios, we constructed lyotropic LC phase diagrams. Interestingly, the appearance of these phase diagrams is greatly different according to the selection of [AA]. Through comparison, we found that the self-organization behavior of an amphiphile in ionic liquids can be tuned by controlling their ability to form hydrogen-bond, van der Waals, and π-π interactions.

N,O-히드록시프로필 키토산들의 열방성과 유방성 액정 거동

치환도(DS) 그리고 몰치환도(MS)가 각각 2.47~2.52 그리고 4.9~7.8 범위에 있는 4 종류의 N,O-히드록시프로필 키토산들(HPCTOs)을 합성함과 동시에 이들의 분자특성과 열방성 및 유방성 특성을 검토하였다. MS는 DS에 비해 대단히 큰 경향을 나타냈다. 이러한 사실은 반응이 진행됨에 따라 프로필렌 옥사이드는 주사슬보다 곁사슬들에 우선적으로 부가됨을 시사한다. 모든 유도체들은 열방성 콜레스테릭 상들을 형성하였다. 유리 그리고 액정 상에서 액체 상으로의 전이 온도들은 MS가 증가함에 따라 낮아졌다. 열방성 콜레스테릭 상들의 광학피치들(<TEX>${\lambda}_m$</TEX>'s)은 온도가 상승함에 따라 증가하였다. 그러나 유도체들이 동일한 온도에서 나타내는 <TEX>${\lambda}_m$</TEX>들은 MS가 증가함에 따라 증가하였다. 고분자의 농도가 30 wt% 이상인 HPCTO들의 물, 메탄올, 에탄올, 아세트산 그리고 포름산 용액들도 고분자의 농도가 증가함에 따라 <TEX>${\lambda}_m$</TEX>이 지수 함수적으로 감소하는 콜레스테릭 상들을 형성하였다. 그러나 HPCTO 용액들의 <TEX>${\lambda}_m$</TEX>의 농도의존성은 용매의 성질과 MS에 민감하게 의존하였다. HPCTO들의 열방성과 유방성 액정 상의 특성들은 히드록시프로필 셀룰로오스들에 대해 보고된 결과들에 비해 현저히 달랐다. 이러한 결과들은 C-2 위치에 존재하는 2차 아미노기가 콜레스테릭 상의 형성능, 안정성 그리고 <TEX>${\lambda}_m$</TEX>의 온도와 농도의존성에 중요한 역할을 함을 시사한다. Four kinds of N,O-hydroxypropyl chitosans (HPCTOs) with degree of substitution(DS) and molar substitution (MS) ranging from 2.47 to 2.52 and 4.9 to 7.8, respectively were synthesized, and their molecular chracteristics and thermotropic and lyotropic liquid crystalline properties were investigated. MS was exceedingly larger than DS, showing that in the later stages of reaction, propylene oxide was preferentially added to the side chains rather than the main chain. All the derivatives formed thermotropic cholesteric phases. The glass and clearing temperatures were decreased with increasing MS. The optical pitches (<TEX>${\lambda}_m$</TEX>'s) of the thermotropic cholesteric phases increased with temperature. However, the <TEX>${\lambda}_m$</TEX>'s of the derivatives at the same temperature increased with increasing MS. Solutions of HPCTOs in water, methanol, ethanol, acetic acid, and formic acid containing more than 30 wt% polymer also formed cholesteic phases whose <TEX>${\lambda}_m$</TEX>'s decreased exponentially with increasing polymer concentration. The concentration dependence of <TEX>${\lambda}_m$</TEX> of HPCTO solutions, however, highly depended on the nature of the solvent and MS. The thermotropic and lyotropic mesophase properties of HPCTOs were significantly different from those reported for hydroxypropyl celluloses. The results indicate that the secondary amino group in the C-2 position plays an important role on the formation, stabilization, and temperature and concentration dependencies of <TEX>${\lambda}_m$</TEX> of the cholesteric mesophase.

Novel ethoxylated inositol derivatives – Hybrid carbohydrate/oligoethylene oxide surfactants

Carbohydrate- and oligoethylene oxide-based surfactants behave quite differently despite the fact that they are both classes of nonionic surfactants. Intensive studies of a mixture at fixed molar ratio (1:1) of two very common sugar- and oligoethylene oxide-based surfactants, namely n-dodecyl-β-d-maltoside (β-C12G2) and n-dodecyl hexaethylene oxide (C12E6), revealed that most properties of the mixture are similar to those of the oligoethylene oxide-based surfactant. In the present work, this mixture is compared to respective “hybrid surfactants”. Such hybrid surfactants are surfactants whose head group contains chemically linked carbohydrate and oligoethylene oxide units. In order to study the behaviour of this sort of compounds, we synthesised a new class of surfactants whose head group consists of one carbohydrate-like unit (myo-inositol) and three ethylene oxide units. New regiochemically defined ethoxylated inositol derivatives (referred to as C12I1E3 and C12E3I1 in the following) were synthesised and studied for their thermotropic and lyotropic liquid crystalline properties as well as for their surface activities. The results are compared with those of the reference systems β-C12G2 and C12E6, and their 1:1 mixture, respectively, and are discussed in terms of structure–property relations.

ChemInform Abstract: Multifunctional Tetracoordinate Phosphorus Species with High Self-Organizing Ability

Abstract The unique features of the phosphonium salts as functional materials are reviewed, with emphasis being placed on the comparison between the phosphonium salts and the commonly available quaternary ammonium salts, which have the same structure, differing only in the positively-charged heteroatom. The antimicrobial activity of onium salts with different long-chain segments is described with special reference to structure–activity relationships. The unexpected relationship between the antibacterial activity and the aggregation behavior in aqueous solution (i.e. lyotropic liquid-crystalline properties) was revealed through systematic studies on the antibacterial activity of the phosphonium salts as a novel class of cationic biocides. Furthermore, it is shown that the phosphonium salts can act as thermotropic liquid crystals in spite of the fact that they are amphiphiles without a rigid core.

Synthesis and characterization on a novel series of protic pyrrolidinium surfactants

A novel series of protic tertiary pyrrolidinium surfactants were prepared and characterized by different techniques. These compounds show good conductivity and efficient ability to reduce surface tension. Thermogravimetric analysis proves their high thermal stability at decomposition temperatures over 250 °C. Their lyotropic and thermotropic liquid crystalline properties are also discussed.

Control of Induced Chirality in Optically Active Poly(N‐propargylcarbamate) Films by Solvent Vapor

Chiral polyethyne derivatives with lyotropic liquid-crystalline properties are found to be able to self-assemble, forming two chiral organizations with opposite handedness in solid thin films by selection of the casting solvent and its concentration. After the film preparation, chiral organization could also be induced by simple exposure to an appropriate organic solvent's vapor for several minutes without thermal treatment. Furthermore, irreversible inversion of the handedness of the chiral organization in the film could be achieved by exposure to solvent vapor.

Poly(pyridinium salt)s with organic counterions derived from an aromatic diamine containing oxyethylene unit exhibiting amphotropic liquid-crystalline and photoluminescence properties

Several poly(pyridinium salt)s containing various organic counterions and oxyethylene unit in their backbones were synthesized by either the ring-transmutation polymerization reaction of 4,4′-(1,4-phenylene)bis(2,6-diphenylpyrylium tosylate) with 1,2-bis(4-aminophenoxy)ethane on heating in dimethyl sulfoxide or the metathesis reaction of the tosylate polymer with the corresponding lithium or sodium salts in acetonitrile. Their chemical structures were determined by 1H and 13C NMR spectroscopy, and elemental analyses. Their number-average molecular weights and polydispersity indices were in the range of 59,000–63,000 and 1.41–1.65, respectively, as determined by gel permeation chromatography. They were characterized for their thermotropic and lyotropic liquid-crystalline properties by using differential scanning calorimetry and polarizing optical microscopy. Since these polymers exhibited liquid-crystalline phase both in the melt and in solutions, they belong to an amphotropic class of ionic polymers. Their light-emitting properties both in polar organic solvents and in films cast from methanol and acetonitrile were also studied by using spectrofluorometry.

Synthesis, thermal and lyotropic liquid crystalline properties of protic ionic salts

A series of protic ionic salts were synthesised by a simple acid–base reaction from various pyridine derivatives and dodecylbenzenesulfonic acid in a common organic solvent and characterised in terms of their thermal and lyotropic liquid crystalline properties using various experimental techniques. All of them exhibited lyotropic liquid crystalline phases in toluene, methanol, acetonitrile, dimethyl sulfoxide and water. Their critical concentrations for the formation of biphasic solutions and concentrations for the formation of lyotropic solutions were quite broad depending on the dielectric constants of the solvents. Their lyotropic phases were identified as lamellar phases, since their textures exhibited bâtonnets, oily streaks and mosaic textures. They can potentially be used for many organic transformations, which may have implications in green chemistry.