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Arthritis is a disease that seriously affects the quality of human life, which is partly caused by the reduction of joint lubrication performance. Thus, for the treatment of arthritis, how to improve the lubrication performance of joints is important. The lamellar liquid crystals (LLCs) systems have the potential to be used as joint lubrication due to their double-layer structure and good biocompatibility, however, the LLCs system alone could not provide a satisfactory lubrication effect. Herein, this work synthesized hydroxyapatite (HAP) in situ inside Tween 85/Tween 80/H 2 O LLCs to construct a biocompatible HAP/Tween 85/Tween 80/H 2 O LLCs (HAP/LLCs) lubrication system with both sustained drug release properties and anti-wear properties. HAP is the main component of bone with good stability and bioactivity. The LLCs have good lubricating and drug-carrying properties. The impact of HAP on the structure and lubrication properties of LLCs, the mechanism of friction, and the anti-wear reduction of HAP/LLCs were investigated. Moreover, the drug release behavior of the ibuprofen-loaded HAP/LLCs during the friction process was also studied. The results indicated that the addition of HAP could improve the lubricity performance of LLCs. The cumulative drug releasing increased with the friction frequency and was less affected by the load. The related studies provided the theoretical basis for HAP/LLCs for joint lubrication and synergistic therapy.

Drying condensed colloid suspension droplet on a horizontal glass substrate has been developed as a simple strategy to fabricate highly-ordered colloidal crystals. A uniform film obtained at above room temperature possessed a face-center-cubic (fcc) crystalline structure and excellent photonic properties. It was found that raising the drying temperature has resulted in a reduction in the lattice spacing of fcc colloidal crystals. The formation reason of uniform fcc colloidal crystals was directly related to the high drying temperature and the large colloid concentration. A ring-shaped stain generated by drying at room temperature has exhibited other highly-ordered microstructures with colloidal crystals, such as body center cubic (bcc) structure., (Copyright © 2013 Elsevier Inc. All rights reserved.)

The individual compounds in an emulsion of tartaric acid stabilized by a commercial surfactant, Laureth 4, were brought into contact in order to estimate the deviation from equilibrium conditions during emulsion evaporation. The transfer of compounds between the phases was followed by visual observation of new phases appearing and the movement of the interfaces with time. The results revealed that, conversely to the equilibrium processes in the corresponding salicylate emulsions, in the present system the dissolution of the acid was faster than the formation of birefringent structures and the variation of different colloidal structures could be followed in the experiment. A suitable choice of initial ratio between the three compounds enabled the transfer of compounds to result in an early depletion of the solid acid and subsequently information could be obtained about the relation between the transport of surfactant and water-acid solution into the birefringent layer. A significant dependence was found between the composition of the entrants into the layer and the amount of surfactant liquid remaining. [ABSTRACT FROM AUTHOR]

Selected pairs of phases in the system, not in equilibrium, were brought into contact and the transport between them was evaluated from the changes in volumes with time. The results showed the rate determining factors to be the extremely slow absorption of compounds into the solid acid layer and of water into the surfactant inverse micellar solution. The former factor was referred to the protracted process of modifying the crystalline structure and the latter to the minute diffusion coefficient of the inverse micelles. In the same manner the contact between the lamellar phase liquid crystalline phase and a solid solution of the surfactant in the acid led to the formation of two inverse micellar solutions of different composition separated by a liquid crystalline layer instead of the expected aqueous liquid and one inverse micellar solution, which appeared first after significantly extended times. The equilibration was significantly retarded by the slow diffusion of acid molecules through one of the liquid layers. [ABSTRACT FROM AUTHOR]

The viscosity during evaporation was determined for emulsions in the system water, vegetable oil, a commercial surfactant, Tween 80R, and the results related to the phases of the emulsion according to the phase diagram. The correlation between the viscosity and the fraction of liquid crystal in the emulsion was pronounced for the emulsions with the oil as the dispersed phase. For the emulsions with oil as the major phase, the effect was significantly less. [ABSTRACT FROM AUTHOR]

Polyaniline (PANI) nanostructures were synthesized in lamellar liquid crystal (LLC) formed by different surfactants. It was found that PANI presented lamellar nanostructures by using the template of LLC formed by ionic surfactant of sodium dodecyl sulfonate (SDS) or hexadecyltrimethylammonium bromide (CTAB), whereas PANI spheric nanostructures were obtained within the LLC template formed by the nonionic surfactant of Triton X-100. The formation mechanisms of PANI nanostructures were discussed. Besides, the lubricating effect of PANI in LLC template was also investigated, and the results showed that spheric PANI had better lubricative performance than lamellar PANI. [ABSTRACT FROM AUTHOR]

A model is presented to provide quantitative measures to estimate the trends of the change in the penetration of the added component into the polar part of the amphiphile layer in lamellar liquid crystals of water and ethoxylated surfactants with added water (or polar solvents). The total thickness of the bi-layer is treated as composed of an aqueous layer, of a layer of the polar groups from the surfactant and of the hydrocarbon chains of the latter. A fraction α of the added water is assumed penetrating the polar group layer leading to its expansion. The evaluation is built on the fact that experimental determinations of the interlayer spacing in the overwhelming majority of cases show a first order linear dependence on the ratio of added water. In the model this linearity is obtained by variation of the degree of penetration of water. The model indicated a reduction in the degree of penetration with added water, which is a rational trend. The model demonstrates the earlier interpretation of a structure, whose interlayer spacing is invariant with water contents as nonswelling; for example, in which all added water penetrates the amhiphile layer, is not appropriate. The model demonstrates the constancy of the interlayer spacing to be a consequence of a balance between the expansion of the amphiphile layer and the increase of a "free water" layer. [ABSTRACT FROM AUTHOR]

Abstract: The microstructure and transformation of the niosome prepared from poly(ethylene glycol) (PEG) 6000/Tween 80/Span 80/H2O lamellar liquid crystal (LLC) are studied by the methods of freeze fracture-TEM, negative-staining TEM, dynamic light scattering technique and micropolarity measurements. The size of the niosome made from the LLC is little larger than that from directly mixing samples. The layer membrane of the former niosome is looser than that of the later niosome. The former niosome is held with the partial behaviors of the LLC and can tend to be transformed into the later niosome. [Copyright &y& Elsevier]

This article reports the lubrication of the mixed system of CdS nanoparticles and Triton X-100/C 10 H 21 OH/H 2 O lamellar liquid crystals. CdS nanoparticles could be synthesized in the lamellar liquid crystal's solvent layer, limited by its amphiphile bilayer. The CdS nanoparticles were spherical and the size was about 5 nm. The lubrication properties of the mixed system of the lamellar liquid crystal and CdS nanoparticles were determined. The results showed that the presence of CdS nanoparticles could improve the antiwear ability and extreme pressure property of Triton X-100/C 10 H 21 OH/H 2 O lamellar liquid crystals. [ABSTRACT FROM AUTHOR]

In the Triton X-100/n-C[sub n]H[sub 2n+1]OH/H[sub 2]O system, the lamellar liquid crystalline region increases and the regions of O/W, W/O and bicontinuous microemulsion domains shrink, simultaneously, with the length of the chain in the unbranched aliphatic alcohol. In the O/W region, the Gibbs free energy for alcohol transfer from the water continuous phase to Triton X-100 micellar phase increases linearly with the chain length of alcohol. In the W/O region of the Triton X-100/n-C[sub n]H[sub 2n+1]OH/ n-C[sub 7]H[sub 16]/H[sub 2]O system, as the solubilized water content increases, the effective radius (R[sub e]), the inner water radius (R[sub W]), the thickness of the interfacial layer (L) and the average aggregation number (ñ) of the reverse micelles increase, whereas the total number (N[sub d]), the total interfacial area (A[sub d]) and the change of the standard free energy (Δ[sub c - i]G[sup 0]) for alcohol transfer from the oil continuous phase to the interfacial layer of the reverse micelles decrease; and with the longer chain alcohols, the values of R[sub e], R[sub W], L, and h all increase, while the Δ[sub c - i]G[sup 0] value decreases drastically with increasing chain length. In the lamellar liquid crystalline region, increasing the alcohol chain length can increase the stability of the lamellar liquid crystalline domain. All the results show that the alcohols, n-C[sub n]H[sub 2n+1]OH, can be used as cosurfactants in the nonionic surfactant system and function similarly as in ionic surfactant systems. [ABSTRACT FROM AUTHOR]

[Display omitted] • Non-aqueous lamellar liquid crystal systems DBSA/MEA was constructed. • DBSA/MEA lamellar liquid crystal system has good lubrication and anti-corrosion properties. • Friction chemical reaction film and adsorption film improves the lubrication performance. • The coordination effect of MEA and Fe may be the key to improve corrosion resistance. Since lamellar liquid crystals (LLCS) could be used for lubrication, many LLCS systems have been constructed to improve lubrication performance. However, most studies focused on the LLCS of the water system, and its corrosiveness brought some limitations to its application. Therefore, it is necessary to construct a non-aqueous LLCS system with good lubrication and anti-corrosion properties to improve its applicability. Anionic surfactant dodecyl benzene sulfonic acid (DBSA) was used to construct non-aqueous LLCS in different solvents, including monoethanolamine (MEA) and diethanolamine (DEA). DBSA/H 2 O LLCS system was constructed for comparison. The LLCS was characterized by polarizing microscope (POM), small-angle X-ray scattering (SAXS), and rheology. Its microstructure was discussed. Meanwhile, we evaluated the lubrication and anti-corrosion performance of LLCS. Its lubrication mechanism was explained through tribology tests and X-ray photoelectron spectrometer (XPS) analysis of the wear scar surface. Its anti-corrosion mechanism was investigated by using the weightlessness method, electrochemical test method, and quantum chemical theoretical calculations. The DBSA/MEA non-aqueous LLCS system showed better lubrication performance than DBSA/DEA and DBSA/H 2 O LLCS. It can adsorb on the surface of the friction pair to form a lubrication friction film, which plays a better role in reducing friction and wear. The DBSA/MEA LLCS is less corrosive to metals because it can effectively isolate oxygen and water in the air between friction pairs. Furthermore, the lone pair electrons in the 2p orbital of the N atom in the MEA molecule could coordinate with the 3d empty orbital of the Fe atom, forming a protective film on the metal surface, which plays a good anti-corrosion effect. This work not only enriched the study of non-aqueous LLCS but also expanded its potential applications in the field of lubrication. [ABSTRACT FROM AUTHOR]

Abstract: Due to the penetration of solvent into the amphiphile bilayer of lamellar liquid crystal and the limitation of the thickness of the solvent layer of the lamellar liquid crystal, the zinc gluconate nanoparticles were synthesized by a direct template route in the lamellar liquid crystal formed by Triton X-100/n-C10H21OH/H2O system. The particles obtained were characterized by the transmission electron microscopy technique. Furthermore, the effects of the composition of lamellar liquid crystal, the zinc gluconate concentration and the temperature on the shape of particles were also studied. The studies show that monodisperse zinc gluconate particles can be produced by the lamellar liquid crystal template, and the shape and size are nearly independent of the composition of lamellar liquid crystal. However, the shape of particles evolves from spheres to nanowires with the increasing zinc gluconate concentration, and from spheres to nanorods as the temperature increases. The formation of one-dimensional zinc gluconate nanostructures can be attributed to an ideal microenvironment in the lamellar liquid crystal. [Copyright &y& Elsevier]

Abstract: The ethylenediaminetetraacetic acid disodium salt (C10H14N2O8Na2) nanoparticles were prepared by replacing water with 3wt% C10H14N2O8Na2 aqueous solution in the lamellar liquid crystal (LLC) of the Triton X-100/n-C10H21OH/H2O system. The particle size is about 5–6nm with relatively narrow distribution. The existing of the C10H14N2O8Na2 nanoparticles in the lamellar liquid crystal can improve the lubrication properties of the lamellar liquid crystal of Triton X-100/n-C10H21OH/H2O system. [Copyright &y& Elsevier]

Abstract: The silver sulfide (Ag2S) nanoparticles were prepared by the reaction of AgNO3 and Na2S in the lamellar liquid crystal (LLC) formed by Triton X-100, n-C10H21OH and H2O. The size of the particles is about 2–3nm. The existence of Ag2S nanoparticles can improve the lubrication of the lamellar liquid crystal. [Copyright &y& Elsevier]

Abstract: Photoisomerization of trans-stilbene (TS) was investigated in sodium dodecyl sulfate (SDS)/benzyl alcohol (BA)/H2O systems in order to establish the relationship between the reaction yields and the compositions and structures of molecular organized assemblies. The results show that, in SDS/BA/H2O systems with the structures of oil in water microemulsions, bicontinuous microemulsions, and hexagonal liquid crystals, the reaction yields are much larger than those in benzyl alcohol, both with and without the photosensitizer 9,10-anthracenedicarbonitrile. However, SDS/BA/H2O water in oil microemulsion and lamellar liquid crystal can obviously catalyze the photoisomerization of TS only when the photosensitizer is not present. The yield is increased with the increase in H2O content or with the decrease in BA content. [Copyright &y& Elsevier]

The applications of ionic liquids (ILs)/lamellar liquid crystals (LLCs) have great potential in nanotribology because they could be used where conventional oils could not work. To clarify the lubricating mechanism, herein, ILs/LLCs lubricants were prepared by addition of amphiphilic 1-alkyl-3-methylimidazolium hexafluorophosphate (C n mimPF 6 , n = 8, 12) into TritonX-100/n-C 10 H 21 OH/H 2 O LLCs with different concentration. The influence of alkyl chain lengths of ILs on the microstructures and the tribological properties of LLCs were investigated. The phase structure parameters and the tribological properties of the LLCs in the presence of C n mimPF 6 were analyzed via freeze-fracture transmission electron microscopy (FF-TEM), the small-angle X-ray scattering (SAXS) technique, oscillating reciprocating friction and wear tester. Compared with the LLCs without C n mimPF 6 , 4.5 wt% C n mimPF 6 /LLCs can reduce the friction and wear of sliding pairs. The better lubricating property and antiwear capability of the C n mimPF 6 /LLCs may be attributed to the increasing of the interlayer thickness d and the decreasing of the bilayer thickness d 0 in microstructures. This work provides a better understanding of the relationship between the microstructures and friction wear performances of ILs/LLCs. [ABSTRACT FROM AUTHOR]

The lamellar liquid crystal (LLCS) system constructed by surfactant aggregation was demonstrated to exhibit superior tribological properties due to its unique lamellar structure and creep recovery properties. However, the lubrication performance of this kind of liquid crystal system was greatly hindered by its soft nature. Emerging as two-dimensional material, MXene has been promising candidate in tribology on account of its unique layer structure and versatile composition. Taking account of the above fact, herein, nonionic surfactant polyoxyethylene lauryl ether (Brij30), MXene (Ti 3 C 2 T x), and H 2 O were employed to construct a triple-component composite LLCS system and the related tribological properties were systematically investigated. The results demonstrated that the lubrication performance of the liquid crystal system formed in the presence of Ti 3 C 2 T x was significantly improved compared with that of Brij30/H 2 O LLCS. The average friction coefficient of the composite LLCS system was in the range of 0.1155–0.1266, and the best lubrication performance was achieved when the Ti 3 C 2 T x content was kept as 6 mg/mL. MXene is also able to achieve good dispersion in liquid crystal systems. The enhanced lubrication performance of the composite LLCS system was mainly due to the synergistic effect of MXene nanosheets and LLCS. In addition, the iron oxides generated by the reaction during the friction process also promote lubrication. It is believed that the current work provides an alternative method for the development of MXene/LLCS-lubricating materials. The Ti 3 C 2 T x /Brij30/H 2 O composite lamellar liquid crystal demonstrates excellent anti-friction and anti-wear performance due to the synergistic effect of friction film and lamellar liquid crystal. [Display omitted] • Nonionic surfactant Brij30, MXene (Ti 3 C 2 T x), and H 2 O were employed to construct a composite lamellar liquid crystal system. • The liquid crystal system improves the dispersion stability of Ti 3 C 2 T x. • The addition of Ti 3 C 2 T x can significantly improve the tribological properties of lamellar liquid crystal. • The uniform dispersion of Ti 3 C 2 T x in the lamellar liquid crystal helps form a protective film during the friction process. [ABSTRACT FROM AUTHOR]

Abstract: Water and a geranyl acetate solution of a non-ionic surfactant, a commercial C12EO4, were brought into contact in amounts to give a combination of a lamellar liquid crystal and an oil phase of equal weights at equilibrium and the equilibration transport between the layers was followed by measuring the change in layer heights with time. The initial reaction, lasting approximately two months, transferred surfactant from the oil phase to combine with water to form a birefringent layer initially containing excess water over the fraction in the liquid crystal in equilibrium with both water and oil phase. After this period the composition of the oil phase had reached a level corresponding to equilibrium with both water and a lamellar liquid crystal, while the birefringent phase, although a liquid crystal, still contained less water fraction than required for equilibrium. The final equilibration process of transferring the excess water to the formed liquid crystal was extremely slow with an estimated time to reach equilibrium of several years. [ABSTRACT FROM AUTHOR]

Abstract: The equilibration between phases in an emulsion of tartaric acid stabilized by a commercial non-ionic surfactant, Laureth 4, was studied by contacting layers of water, tartaric acid and surfactant and measuring the change of layer heights with time. Contrary to earlier results of similar investigations with salicylic acid, the present determinations disclosed the transfer of compounds between the solid acid phase and the liquids not to be the primary rate-determining step in the equilibration process. Instead this stage was found in the surfactant liquid and the aqueous solution of the acid generating a lamellar liquid crystal. The results revealed a surprising number of different mechanisms involved in the transfers of compounds between the phases as exemplified by the fact that initially the formed liquid crystal was dispersed in the aqueous liquid forming a birefringent layer, a significant fraction of which was the aqueous phase. At intermediate times in the process a fraction of liquid crystal from the aqueous layer was redispersed into the surfactant liquid, in which the newly generated liquid crystal was also dispersed, but now the birefringent parts were of a more complex structure. In the final stage of the investigation but little liquid crystal was produced and the birefringent generating elements in the surfactant liquid layer were spontaneously redispersed into a liquid crystal in the aqueous stratum. [Copyright &y& Elsevier]