| 1. |
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| 2. |
- Berger, Patricia Sara, et al.
(författare)
-
Methods for treating glassware surfaces using corrosion protection agents.
- 2004
-
Patent (populärvet., debatt m.m.)abstract
- A domestic, institutional, industrial, and/or com. method of reducing glassware surface corrosion in an automatic dishwashing appliance comprises the step of contacting a glassware surface with a corrosion protection agent comprising: (a) an effective amt. of a zinc-contg. layered material, said material having a particle size in the range of about 1 nm to about 100 nm and a crystallinity value of from about 0.4 to about 0.8625 FWHM units, at a 200 reflective peak; and (b) optionally, an adjunct ingredient and (c) a dispersant polymer: said contacting being done at a pH greater than 9 to about 14. Methods using corrosion protection agents that form a part of a treatment system and/or are incorporated in a compn. of matter are also provided. [on SciFinder(R)]
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| 3. |
- Corkery, Robert W., 1967-, et al.
(författare)
-
Polymeric composition, adhesive including nanoparticle filler and composite production.
- 2006
-
Patent (populärvet., debatt m.m.)abstract
- Nanoparticle fillers, including a novel halloysite nanoparticle filler, are generally cylindrical or tubular nanoparticles (e.g. rolled scroll-like shape). The filler is effectively employed in a polymer nanoparticle adhesive composite, contg. the halloysite nanoparticle or other equiv. naturally occurring nanotubular filler, in which the advantages of the nanoparticle filler are provided (e.g., reinforcement, flame retardant, etc.) while maintaining or improving mech. performance of the adhesive composite (e.g., adhesive strength and tack). [on SciFinder(R)]
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| 4. |
- Li, Yaqiong, et al.
(författare)
-
Characterization of red-shifted phycobilisomes isolated from the chlorophyll f-containing cyanobacterium Halomicronema hongdechloris
- 2016
-
Ingår i: Biochimica et Biophysica Acta - Bioenergetics. - : Elsevier. - 0005-2728 .- 1879-2650. ; 1857:1, s. 107-114
-
Tidskriftsartikel (refereegranskat)abstract
- Phycobilisomes are the main light-harvesting protein complexes in cyanobacteria and some algae. It is commonly accepted that these complexes only absorb green and orange light, complementing chlorophyll absorbance. Here, we present a new phycobilisome derived complex that consists only of allophycocyanin core subunits, having red-shifted absorption peaks of 653 and 712 nm. These red-shifted phycobiliprotein complexes were isolated from the chlorophyll f-containing cyanobacterium, Halomicronema hongdechloris, grown under monochromatic 730 nm-wavelength (far-red) light. The 3D model obtained from single particle analysis reveals a double disk assembly of 120-145 angstrom with two alpha/beta allophycocyanin trimers fitting into the two separated disks. They are significantly smaller than typical phycobilisomes formed from allophycocyanin subunits and core-membrane linker proteins, which fit well with a reduced distance between thylakoid membranes observed from cells grown under far-red light. Spectral analysis of the dissociated and denatured phycobiliprotein complexes grown under both these light conditions shows that the same bilin chromophore, phycocyanobilin, is exclusively used. Our findings show that red-shifted phycobilisomes are required for assisting efficient far-red light harvesting. Their discovery provides new insights into the molecular mechanisms of light harvesting under extreme conditions for photosynthesis, as well as the strategies involved in flexible chromatic acclimation to diverse light conditions.
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| 5. |
- Song, Brian Xiaoqing, et al.
(författare)
-
Complete-cycle methods for protecting glassware from surface corrosion in automatic dishwashing appliances
- 2007
-
Patent (populärvet., debatt m.m.)abstract
- Complete-cycle methods for protecting glassware from corrosion in automatic dishwashing appliances use a through-the-wash detergent compn., esp. detergent compns. comprising zinc-contg. materials, in combination with a rinse aid compn., esp. rinse aid compns. comprising at least one water-sol. metal salt. Such a domestic, institutional, industrial, and/or com. complete-cycle method of treating glassware surfaces in automatic dishwashing comprises the steps of: (a) providing a through-the-wash detergent compn. comprising an effective amt. of a particulate zinc-contg. material; (b) providing a rinse aid compn. comprising an effective amt. of at least one metal salt; (c) contacting said glassware surface with said through-the-wash detergent compn.; and (d) contacting said glassware surface with said rinse aid compn. in the rinse cycle. [on SciFinder(R)]
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| 6. |
- Song, Brian Xiaoqing, et al.
(författare)
-
Complete-cycle methods for protecting glassware from surface corrosion in automatic dishwashing appliances
- 2003
-
Patent (populärvet., debatt m.m.)abstract
- Detergent compns. comprising zinc-contg. materials, are used to protect glassware from surface corrosion during automatic dishwashing. A domestic, institutional, industrial, and/or com. through-the-wash method of treating glassware in automatic dishwashing process, comprises the step of contacting a glassware surface with a through-the-wash automatic dishwashing detergent compn. comprising: (a) an effective amt. of a zinc-contg. layered material; (b) a detergent active; (c) optionally, one or more of the following: a dispersant polymer or carrier medium; and (d) optionally, an adjunct ingredient. [on SciFinder(R)]
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| 7. |
- Song, Brian Xiaoqing, et al.
(författare)
-
Compositions for protecting glassware from surface corrosion in automatic dishwashing appliances
- 2003
-
Patent (populärvet., debatt m.m.)abstract
- Through-the-wash automatic dishwashing detergent compns., esp. detergent compns. comprising zinc-contg. materials, are used to protect glassware from surface corrosion during automatic dishwashing. Such a domestic, institutional, industrial, and/or com. through-the-wash automatic dishwashing detergent compn. comprises: (a) an effective amt. of a zinc-contg. layered material; (b) a detergent active; (c) optionally, one or more of the following: a dispersant polymer or carrier medium; and (d) optionally, an adjunct ingredient. [on SciFinder(R)]
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| 8. |
- Song, Brian Xiaoqing, et al.
(författare)
-
Methods for treating glassware surfaces using zinc-containing corrosion protection agents.
- 2003
-
Patent (populärvet., debatt m.m.)abstract
- A treatment system corrosion protection agents, esp. corrosion protection agents comprising zinc-contg. materials, is used for treating glassware for example dishes and glasses, with reduced surface corrosion. Such a domestic, institutional, industrial, and/or com. method of reducing glassware surface corrosion in an automatic dishwashing appliance comprises the step of contacting a glassware surface with a corrosion protection agent comprising: (a) an effective amt. of a zinc-contg. layered material; and (b) optionally, an adjunct ingredient. [on SciFinder(R)]
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| 9. |
- Sörensen, Malin H., et al.
(författare)
-
AFM-Porosimetry : Density and pore volume measurements ofparticulate materials
- 2008
-
Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 24, s. 7024-7030
-
Tidskriftsartikel (refereegranskat)abstract
- We introduced the novel technique of AFM-porosimetry and applied it to measure the total pore volume of porous particles with a spherical geometry. The methodology is based on using an atomic force microscope as a balance to measure masses of individual particles. Several particles within the same batch were measured, and by plotting particle mass versus particle volume, the bulk density of the sample can be extracted from the slope of the linear fit. The pore volume is then calculated from the densities of the bulk and matrix materials, respectively. In contrast to nitrogen sorption and mercury porosimetry, this method is capable of measuring the total pore volume regardless of pore size distribution and pore connectivity. In this study, three porous samples were investigated by AFM-porosimetry: one ordered mesoporous sample and two disordered foam structures. All samples were based on a matrix of amorphous silica templated by a block copolymer, Pluronic F127, swollen to various degrees with poly(propylene glycol). In addition, the density of silica spheres without a template was measured by two independent techniques: AFM and the Archimedes principle.
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| 10. |
- Alberius, Peter Carl Anders, et al.
(författare)
-
Cosmetic compositions comprising dye-loaded particles.
- 2007
-
Patent (populärvet., debatt m.m.)abstract
- According to the invention, a cosmetic compn. is provided comprising: (a) amorphous particles, each amorphous particle comprising a homogeneous distribution of one or more dyes encapsulated by an amorphous, siliceous encapsulating agent, wherein the amorphous particle comprises from 3% to 20%, preferably 5% to 15%, more preferably 8% to 12% dye, by wt. of the particle; (b) a cosmetically acceptable carrier. Silica loaded with tartrazine and other dyes are prepd. Cosmetic compns. such as lipsticks and mascaras are prepd. contg. encapsulated dyes, siloxanes and other ingredients. [on SciFinder(R)]
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| 11. |
- Alberius, Peter Carl Anders, et al.
(författare)
-
Dye-loaded particles.
- 2007
-
Patent (populärvet., debatt m.m.)abstract
- Amorphous particles are provided comprising a homogeneous distribution of one or more dyes encapsulated by an amorphous, siliceous encapsulating agent, wherein the amorphous particle comprises from 3% to 20% dye, by wt. of the particle. [on SciFinder(R)]
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| 12. |
- Alberius, Peter Carl Anders, et al.
(författare)
-
Spray-drying process for the manufacture of dye-loaded particles.
- 2007
-
Patent (populärvet., debatt m.m.)abstract
- According to a first aspect of the invention, a process is provided for the prepn. of amorphous particles comprising a homogeneous distribution of one or more dyes encapsulated by an amorphous, siliceous encapsulating agent, the process comprising: (a) providing a precursor of the encapsulating agent in liq. form; (b) providing the one or more dyes in liq. form; (c) mixing the liq. forms; (d) spraying the mixt. to form droplets comprising the one or more dyes and encapsulating agent; and (e) heating the droplets to form the particles comprising the one or more dyes encapsulated by the siliceous encapsulating agent; wherein at least one of the liq. forms provided is aq. and the or each aq. liq. form is acidic. According to a second aspect of the invention, encapsulated dyes made by the process of the first aspect of the invention are provided. [on SciFinder(R)]
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| 13. |
- Andersson, Nina, et al.
(författare)
-
Combined Emulsion and Solvent Evaporation (ESE) Synthesis Route to Well-Ordered Mesoporous Materials
- 2007
-
Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 23:3, s. 1459-1464
-
Tidskriftsartikel (refereegranskat)abstract
- Control over morphol. and internal mesostructure of surfactant templated silicas remains a challenge, esp. when considering scaling lab. syntheses up to industrial vols. Here we report a method combining emulsification with the evapn.-induced self-assembly (EISA) method for prepg. spherical, mesoporous silica particles. This emulsion and solvent evapn. (ESE) method has several potential advantages over classic pptn. routes: it is easily scaled while providing superior control over stoichiometric homogeneity of templating surfactants and inorg. precursors, and particle sizes and distributions are detd. by principles developed for manipulating droplet sizes within water-in-oil emulsions. To demonstrate the method, triblock copolymer P104 is used as a templating amphiphile, generating unusually well-ordered 2D hexagonal (P6mm) mesoporous silica, while particle sizes and morphologies were controlled by varying the type of emulsifier and the method for emulsification. [on SciFinder(R)]
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| 14. |
- Andersson, Nina, et al.
(författare)
-
One-Pot Synthesis of Well-Ordered Mesoporous Magnetic Carriers
- 2007
-
Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 17:26, s. 2700-2705
-
Tidskriftsartikel (refereegranskat)abstract
- The facile preparation of a mesoporous magnetic carrier technology is demonstrated. The micron-sized spherical mesostructured particles are prepared using a newly-developed, one-step, combined emulsion and solvent evaporation (ESE) method. The surfactant-templated silica matrix display a well-ordered internal pore architecture. Very limited pore blocking, and only to a limited degree disordered- or worm-like structures are observed, induced by the iron oxide nanoparticles added to provide the superparamagnetic properties.The iron oxide content was precisely controlled, and the magnetic properties were well preserved during the process. Finally we demonstrate the applicability of the magnetically separable mesoporous material as an adsorbent for specific dissolved materials from dilute aqueous solutions.
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| 15. |
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| 16. |
- Corkery, Robert W., 1967-, et al.
(författare)
-
A case for discotic liquid crystals in molten triglycerides
- 2007
-
Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 23, s. 7241-7246
-
Tidskriftsartikel (refereegranskat)abstract
- To date, essentially only two structural models have been proposed and debated in detail for explaining the liquid state order of triglycerides, and both invoke a form of thermotropic liquid crystalline order in triglyceride melts. These are the paralamellar model of Larsson et al. (J. Am. Oil Chem. Soc. 1992, 69, 835) and the nematic model of Cebula et al. (J. Am. Oil Chem Soc. 1992, 69, 130). An alternative discotic model is proposed here that adequately accounts for the broad small-angle X-ray diffraction peak often observed in the liquid state of fats and oils. In this alternative model, triglyceride molecules exist in the liquid state with fully splayed chains, approximating "Y"-shapes (Y-conformers). These are loosely bound within discs that stack into flexible, relatively short cylindrical rods of colloidal dimension, which in turn assemble into rod-packings with short-range order akin to disordered versions of thermotropic discotic liquid crystalline phases in other lipidic systems.
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| 17. |
- Corkery, Robert W., 1967-
(författare)
-
A variation on Luzzati's soap phases : Room temperature thermotropic liquid crystals
- 2004
-
Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 6:7, s. 1534-1546
-
Tidskriftsartikel (refereegranskat)abstract
- Remarkable room-temp. liq. crystallinity is obsd. for a wide range of metal soaps. Incorporation of satd., mid-chain mono-Me branched C17 fatty acid (mid-chain branched fatty acid) into metal soaps lowers the liq. cryst. transition to below room temp. Soaps of Na, Mg, Al, Ca, Cu, Zn, Sr, Ag, Cd, La, Ce, Tb and Lu were synthesized and characterized via XRD, FTIR, DSC, optical microscopy, d. detns. and other phys. methods. The main room temp. mesophase identified in the soaps here is a liq. cryst. hexagonal columnar phase, 1st described by Luzzati et al. A comparative anal. of the branched soaps with their satd., linear analogs is given. Implications for room temp. columnar soap structure is discussed in terms of the various phys. parameters found for these soaps.
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| 18. |
- Corkery, Robert W., 1967-, et al.
(författare)
-
Anti-caking agent for flavored products
- 2010
-
Patent (populärvet., debatt m.m.)abstract
- The present invention generally relates to the use of porous particles to control the release of a liquid, such as the release of a flavor in a food product. Liquid components, such as flavorants, are loaded into porous particles to form a composition. The pore diameter, pore tortuosity and loading parameters determine the characteristics of the composition and the release profile of the liquid.
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| 19. |
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| 20. |
- Corkery, Robert W., 1967-
(författare)
-
Aspects of the differential geometry and topology of bicontinuous liquid-crystalline phases
- 2005
-
Ingår i: Surfactant Sci. Ser.. - 0081-9603. ; 127:Bicontinuous Liquid Crystals, s. 99-127
-
Tidskriftsartikel (refereegranskat)abstract
- A review. This chapter provides a semiformal, though largely qual., look at the mathematics of triply periodic minimal surfaces (TPMS) in relation to bicontinuous and polycontinuous liq. crystals. It is motivated largely by research of Stephen Hyde and others at the Applied Mathematics Department, Australian National University, Canberra, Australia and by the discovery of these TPMS liq. crystal partitions by Kare Larsson and the late Krister Fontell at Lund University. The article is meant to complement the existing, more rigorous papers and provide an introduction to the more fundamental topics of differential geometry and topol. of TPMS. Bicontinuous liq. crystals contain 2 mutually interpenetrating labyrinths sepd. by a hyperbolic partition that is often best described as a triply periodic minimal surface (TPMS). Properties of these surfaces can be broken down into local and global types. Local properties pertain to small, isolated surface patches and include intrinsic measures such as the metric, surface areas, and angles and the Gaussian curvature. The global properties require a look at the surface as a whole, embedded in 3D space. The global measures include parameters such as the Cartesian coordinates, topol., curvature distributions, and overall symmetries. These local and global properties are connected through the Gauss-Bonnet theorem that relates the topol. to the Gaussian curvature. For the simplest TPMS, such as the P, D, and G surfaces, the local Gaussian curvature detd. from small patches of the surface can give information regarding the stability of bicontinuous liq. crystals. For some simpler TPMS, the small surface patches are polygonal (e.g., triangles), according to the various symmetries of the surface. These small 2D surface patches can be built up into the entire 3D surface using various 3D construction algorithms based on symmetries, the same way 3D crystals can be built up from unique atoms. Alternatively these patches can be usefully represented in 2 dimensions by various mappings to the sphere, hyperbolic plane, and complex plane; then built up in those spaces using analogous symmetry operations; and then embedded in 3D space by folding and "gluing" the edges of the 2D representations. The 2D forms of these surfaces offer simple ways of constructing known and novel surfaces, algorithmically, and also explicitly through the Weierstrass parametrization, which gives the exact and explicit (x,y,z) coordinates of the actual minimal surface (not approximates) via the complex plane representation. Armed with this explicit information, modeling the stabilities, phase changes, and other phys. processes involving these minimal surfaces is rigorously quantifiable from a geometric perspective. A novel, topol.-preserving phase transformation between the P, D, and G cubic phases arises directly from the anal. of rhombohedral and tetrahedral distortions of the P, D, and G surfaces using this method. Networks decorating TPMS are of interest for generating and analyzing crystal networks. The simplest networks overlay the polygonally decorated surfaces built up of the fundamental patches. Families of networks can be generated for individual TPMS using supergroup-subgroup symmetry relationships between the decorating tesselation and the underlying symmetry elements of the TPMS itself. Of direct relevance to liq. cryst. mesophases is the set of polycontinuous networks that can be generated on various TPMS. These are generated by commensurately decorating 2D surface representations of TPMS with tree networks. With some well-chosen constraints, folding and gluing operations can result in surfaces decorated by entangled thickets of unconnected networks. In turn, these embedded networks can be used to form tri-, quadra-, octa- and other polycontinuous morphologies, with their resp. mutually interpenetrating labyrinths sepd. by a single triply periodic minimal surface.
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| 21. |
- Corkery, Robert W., 1967-, et al.
(författare)
-
Emulsion inversion in the PIT range: Quantitative phase variations in a two-phase emulsion
- 2010
-
Ingår i: Journal of Chemical and Engineering Data. - : American Chemical Society (ACS). - 0021-9568 .- 1520-5134. ; 55:10, s. 4471-4475
-
Tidskriftsartikel (refereegranskat)abstract
- The phase-inversion temperature (PIT) phenomenon is for the first time given a quantitative treatment for systems having a sufficiently small surfactant content to be limited to two phases at the PIT. The results show that the early opinion of a phase transfer of the surfactant as the major event in the transversal of the temperature range is not entirely correct; the major phenomenon is instead an expulsion of water from the low-temperature aqueous micellar solution. In addition, the results unexpectedly give an indication of the existence of three phases at temperatures beneath the PIT, in spite of the the fact that system consists of only two phases at the actual PIT.
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| 22. |
- Corkery, Robert W., 1967-
(författare)
-
Metal organic framework (MOF) liquid crystals : 1D, 2D and 3D ionic coordination polymer structures in the thermotropic mesophases of metal soaps, including alkaline earth, transition metal and lanthanide soaps
- 2008
-
Ingår i: Current Opinion in Colloid & Interface Science. - : Elsevier BV. - 1359-0294 .- 1879-0399. ; 13:4, s. 288-302
-
Tidskriftsartikel (refereegranskat)abstract
- aken together, the body of existing literature on metal soap crystal structures and mesophases supports the view that much is to be gained by treating the soaps as metal organic frameworks (MOF's) when relating their structure and liquid crystallinity. We argue that metal soaps mesophases often consist of disordered metal organic (carboxylate) frameworks (MOF's). Metal atoms are linked by bridging carboxylates, and the metal-oxygen networks form semi-flexible rods, chains and sheets of M-O polyhedra within their co-bonded, mesotructured, self-assemblies of lipidic chains. The packing of the molten hydrocarbon chains allows otherwise unconnected MOF networks to coexist as spatially isolated units in the same unit cell. For instance the lamellar phases are true 2D MOF's or layers of 1-D MOF's. The phase transitions can then be regarded as coupled disordering/re-ordering transitions involving rotational and conformational disordering of the hydrocarbon chains balanced with disordering of MOF symmetries, MOF topological transformations, depolymerizations and dimensionality reductions ultimately leading to anisotropic melts. By way of demonstration, thermotropic phase transitions of homologous series of lanthanide soaps are systematically studied using a variety of experimental methods, and the data are used in a topological model for testing the consistency with the MOF concept of metal soap crystal structures and thermotropic: mesophases. Finally, an interpenetrating bicontinuous MOF comprised of SrO6 polyhedral rods is presented as an atomically resolved model for the network topology of the cubic mesophase of strontium soaps. Metal soaps are therefore shown to afford a bridge between liquid crystals and metal organic framework (MOF) materials.
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| 23. |
- Corkery, Robert W., et al.
(författare)
-
On the colour of wing scales in butterflies : Iridescence and preferred orientation of single gyroid photonic crystals
- 2017
-
Ingår i: Interface Focus. - : Royal Society. - 2042-8898 .- 2042-8901. ; 7:4
-
Tidskriftsartikel (refereegranskat)abstract
- Lycaenid butterflies from the genera Callophrys, Cyanophrys and Thecla have evolved remarkable biophotonic gyroid nanostructures within their wing scales that have only recently been replicated by nanoscale additive manufacturing. These nanostructures selectively reflect parts of the visible spectrum to give their characteristic non-iridescent, matte-green appearance, despite a distinct blue-green-yellow iridescence predicted for individual crystals from theory. It has been hypothesized that the organism must achieve its uniform appearance by growing crystals with some restrictions on the possible distribution of orientations, yet preferential orientation observed in Callophrys rubi confirms that this distribution need not be uniform. By analysing scanning electron microscope and optical images of 912 crystals in three wing scales, we find no preference for their rotational alignment in the plane of the scales. However, crystal orientation normal to the scale was highly correlated to their colour at low (conical) angles of view and illumination. This correlation enabled the use of optical images, each containing up to 104-105 crystals, for concluding the preferential alignment seen along the k100l at the level of single scales, appears ubiquitous. By contrast, k110l orientations were found to occur at no greater rate than that expected by chance. Above a critical cone angle, all crystals reflected bright green light indicating the dominant light scattering is due to the predicted band gap along the k110l direction, independent of the domain orientation. Together with the natural variation in scale and wing shapes, we can readily understand the detailed mechanism of uniform colour production and iridescence suppression in these butterflies. It appears that the combination of preferential alignment normal to the wing scale, and uniform distribution within the plane is a near optimal solution for homogenizing the angular distribution of the k110l band gap relative to the wings. Finally, the distributions of orientations, shapes, sizes and degree of order of crystals within single scales provide useful insights for understanding the mechanisms at play in the formation of these biophotonic nanostructures.
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| 24. |
- Corkery, Robert W, 1967-, et al.
(författare)
-
On the formation and structure of nanometric polyhedral foams : toward the dry limit
- 2008
-
Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 24:18, s. 10443-10452
-
Tidskriftsartikel (refereegranskat)abstract
- High surface area, high porosity, nanometric polygonal silica foams with hierarchically connected and uniformly sized pore systems are reported here. We observe a remarkable increase in foam cell sizes from mesoscopic to macroscopic dimensions upon swelling the self-assembled template with oil. The resultant structures resemble classical macroscopic soap foams and display, among other features, Plateau borders and volume fractions approaching the dry limit of 100%. In well-developed foams of this kind, dimensionally isometric polyhedral cells are connected by relatively short, flat cylindrical mesopores through polyhedral faces and micropores through the walls. For one sample, with approximately 75 nm diameter primary foam cells, we infer three separate sets of cell-connecting mesopores puncturing tetragonal, pentagonal, and hexagonal faces of the component polyhedra. A multiple step model of foam formation is discussed where an organic silica precursor progressively hydrolyzes and condenses as a growing flexible shell from the core-corona interface of oil-swollen triblock copolymer micelles or microemulsion droplets, inducing a clouding phenomena in the otherwise stabilizing poly(ethylene oxide) chains, leading to aggregation, deformation, and jamming to high volume fractions.
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| 25. |
- Corkery, Robert W., 1967-, et al.
(författare)
-
Polymeric coatings including nanoparticle filler
- 2007
-
Patent (populärvet., debatt m.m.)abstract
- Disclosed is a polymeric composite coating including a nanoparticle filler, where the filler may be suitable to alter one or more characteristics of the coating. More particularly, one embodiment of the present invention provides a halloysite nanoparticle filler which has the general configuration of a cylinder or a rolled scroll-like shape, and a polymer protective coating contg. the halloysite nanoparticle or equiv. nanotubular filler. [on SciFinder(R)]
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| 26. |
- Deguchi, Shigeru, et al.
(författare)
-
Microbial growth at hyperaccelerations up to 403,627 x g
- 2011
-
Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 108:19, s. 7997-8002
-
Tidskriftsartikel (refereegranskat)abstract
- It is well known that prokaryotic life can withstand extremes of temperature, pH, pressure, and radiation. Little is known about the proliferation of prokaryotic life under conditions of hyperacceleration attributable to extreme gravity, however. We found that living organisms can be surprisingly proliferative during hyperacceleration. In tests reported here, a variety of microorganisms, including Gram-negative Escherichia coli, Paracoccus denitrificans, and Shewanella amazonensis; Gram-positive Lactobacillus delbrueckii; and eukaryotic Saccharomyces cerevisiae, were cultured while being subjected to hyperaccelerative conditions. We observed and quantified robust cellular growth in these cultures across a wide range of hyperacceleration values. Most notably, the organisms P. denitrificans and E. coli were able to proliferate even at 403, 627 x g. Analysis shows that the small size of prokaryotic cells is essential for their proliferation under conditions of hyperacceleration. Our results indicate that microorganisms cannot only survive during hyperacceleration but can display such robust proliferative behavior that the habitability of extraterrestrial environments must not be limited by gravity.
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| 27. |
- Dobryden, Illia, et al.
(författare)
-
Local Wear of Catechol-Containing Diblock Copolymer Layers : Wear Volume, Stick-Slip, and Nanomechanical Changes
- 2021
-
Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society. - 1932-7447 .- 1932-7455. ; 125:38, s. 21277-21292
-
Tidskriftsartikel (refereegranskat)abstract
- Polymers containing catechol groups have gained a large interest, as they mimic an essential feature of mussel adhesive proteins that allow strong binding to a large variety of surfaces under water. This feature has made this class of polymers interesting for surface modification purposes, as layer functionalities can be introduced by a simple adsorption process, where the catechol groups should provide a strong anchoring to the surface. In this work, we utilize an AFM-based method to evaluate the wear resistance of such polymer layers in water and compare it with that offered by electrostatically driven adsorption. We pay particular attention to two block copolymer systems where the anchoring group in one case is an uncharged catechol-containing block and in the other case a positively charged and catechol-containing block. The wear resistance is evaluated in terms of wear volume, and here, we compare with data for similar copolymers with statistical distribution of the catechol groups. Monitoring of nanomechanical properties provides an alternative way of illustrating the effect of wear, and we use modeling to show that the stiffness, as probed by an AFM tip, of the soft layer residing on a hard substrate increases as the thickness of the layer decreases. The stick-slip characteristics are also evaluated. © 2021 The Authors.
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| 28. |
- Fiedler, J., et al.
(författare)
-
Perspectives on weak interactions in complex materials at different length scales
- 2023
-
Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 25:4, s. 2671-2705
-
Forskningsöversikt (refereegranskat)abstract
- Nanocomposite materials consist of nanometer-sized quantum objects such as atoms, molecules, voids or nanoparticles embedded in a host material. These quantum objects can be exploited as a super-structure, which can be designed to create material properties targeted for specific applications. For electromagnetism, such targeted properties include field enhancements around the bandgap of a semiconductor used for solar cells, directional decay in topological insulators, high kinetic inductance in superconducting circuits, and many more. Despite very different application areas, all of these properties are united by the common aim of exploiting collective interaction effects between quantum objects. The literature on the topic spreads over very many different disciplines and scientific communities. In this review, we present a cross-disciplinary overview of different approaches for the creation, analysis and theoretical description of nanocomposites with applications related to electromagnetic properties.
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| 29. |
- Fogden, Andrew, et al.
(författare)
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An aqueous dispersion, a coated subject and use of an aqueous dispersion
- 2007
-
Patent (populärvet., debatt m.m.)abstract
- There is disclosed an aqueous dispersion comprising a) inorganic particles b) at least one fatty acid or a salt thereof, c) a polymeric binder, and d) water, wherein said aqueous dispersion is free of organic solvent. There is also disclosed use of an aqueous dispersion comprising a) inorganic particles, b) at least one fatty acid or a salt thereof, c) a polymeric binder, and d) water, as a coating on a substrate surface, wherein said surface after coating displays an equilibrium contact angle higher than 120° degrees, preferably more than 135°, most preferably more than 150° for a drop of water on the surface. There is also disclosed a method for coating a substrate comprising contacting said substrate with the aqueous dispersion. The coating allows application in one step, it is non-toxic, safe for food packaging, and environmentally friendly as well as inexpensive.
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| 30. |
- Fogden, Andrew, et al.
(författare)
-
An aqueous hydrophobic coating composition comprising a fatty acid or a salt thereof
- 2007
-
Patent (populärvet., debatt m.m.)abstract
- There is disclosed an aqueous dispersion to be used in the manufacture of a hydrophobic coating, wherein said aqueous dispersion comprises: inorganic particles, at least one fatty acid or a salt thereof, a polymeric binder, and water. There is further disclosed a method for preparing an aqueous dispersion and a method of coating a substrate. There is also disclosed a subject coated with the method. The coating can be applied in one step, it is non-toxic, safe for food packaging, and relatively environmentally friendly as well as inexpensive.
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| 31. |
- Friberg, Stig E, et al.
(författare)
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Phase inversion temperature (PIT) emulsification process
- 2011
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Ingår i: Journal of Chemical and Engineering Data. - : American Chemical Society (ACS). - 0021-9568 .- 1520-5134. ; 56:12, s. 4282-4290
-
Tidskriftsartikel (refereegranskat)abstract
- A quantitative analysis is made of the phase changes during the phase inversion temperature (PIT) emulsification process of an aqueous hexadecane emulsion stabilized by a tetra-ethylene glycol dodecyl ether surfactant. The mechanical dispersion part of the process takes place at the PIT, at which temperature the emulsion contains three phases: (1) water, with only minute fractions of surfactant and hydrocarbon; (2) an inverse micellar solution, with modest fractions of solubilized water; and (3) a bicontinuous microemulsion, with large concurrent solubilization of both water and hydrocarbon. After the mechanical action at the PIT, the emulsion is immediately cooled to temperatures beneath the PIT range, reducing the number of phases in the emulsion to two, an oil/water (O/W) microemulsion with moderate surfactant and hydrocarbon content, and an inverse micellar hydrocarbon solution with a significantly greater surfactant fraction. The emulsion is characterized by its large fraction of extremely small oil drops, significantly smaller than expected from the mechanical process. These drops are commonly assumed to emanate from the hydrocarbon fraction of the original bicontinuous microemulsion, the small size of the oil drops being a rational consequence of the colloidal dispersion prior to the phase separation. The quantitative analysis of the phase fractions versus temperature revealed this assumption to be premature. The original water phase is not the final aqueous phase in the emulsion; this phase is instead formed from the microemulsion phase by absorbing the original water phase, gradually modifying its own structure to become water-continuous with the originally large hydrocarbon fraction reduced to modest levels. In the process, a part of the original microemulsion is separated, forming the small oil drops.
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| 32. |
- He, Yunjuan, et al.
(författare)
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Nano-scale mechanical and wear properties of a waterborne hydroxyacrylic-melamine anti-corrosion coating
- 2018
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Ingår i: Applied Surface Science. - : Elsevier BV. - 0169-4332 .- 1873-5584. ; 457, s. 548-558
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Tidskriftsartikel (refereegranskat)abstract
- Corrosion protection is commonly achieved by applying a thin polymer coating on the metal surface. Many studies have been devoted to local events occurring at the metal surface leading to local or general corrosion. In contrast, changes occurring in the organic coating after exposure to corrosive conditions are much less studied. In this article we outline how changes in the coating itself due to curing conditions, environmental and erosion effects can be investigated at the nanometer scale, and discuss how such changes would affect its corrosion protection performance. We focus on a waterborne hydroxyacrylic-melamine coating, showing high corrosion protection performance for carbon steel during long-term (≈35 days) exposure to 0.1 M NaCl solution. The effect of curing time on the conversion of the crosslinking reaction within the coating was evaluated by fourier transform infrared spectroscopy (FTIR); the wetting properties of the cured films were investigated by contact angle measurement, and the corrosion resistance was studied by electrochemical impedance spectroscopy (EIS). In particular, coating nanomechanical and wear properties before and after exposure to 0.1 M NaCl, were evaluated by atomic force microscopy (AFM). Fiber-like surface features were observed after exposure, which are suggested to arise due to diffusion of monomers or low molecular weight polymers to the surface. This may give rise to local weakening of the coating, leading to local corrosion after even longer exposure times. We also find a direct correlation between the stick-slip spacing during shearing and plastic deformation induced in the surface layer, giving rise to topographical ripple structures on the nanometer length scale.
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| 33. |
- Hermans, J. J., et al.
(författare)
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Ionomer-like structure in mature oil paint binding media
- 2016
-
Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 6:96, s. 93363-93369
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Tidskriftsartikel (refereegranskat)abstract
- Infrared spectra of samples from oil paintings often show metal carboxylate bands that are broader and shifted compared to those of crystalline metal soap standards (metal complexes of long-chain saturated fatty acids). Using quantitative attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), it is demonstrated that the broad metal carboxylate band is typically too intense to be explained by carboxylates adsorbed on the surface of pigment particles or disordered metal complexes of saturated fatty acids. The metal carboxylate species associated with the broad bands must therefore be an integral part of the polymerized binding medium. Small-angle X-ray scattering (SAXS) measurements on model ionomer systems based on linseed oil revealed that the medium contains ionic clusters similar to more classical ionomers. These structural similarities are very helpful in understanding the chemistry of mature oil paint binding media and the potential degradation mechanisms that affect oil paintings.
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| 34. |
- Hermans, Joen J., et al.
(författare)
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The molecular structure of three types of long-chain zinc(II) alkanoates for the study of oil paint degradation
- 2014
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Ingår i: Polyhedron. - : Elsevier BV. - 0277-5387 .- 1873-3719. ; 81, s. 335-340
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Tidskriftsartikel (refereegranskat)abstract
- The molecular structures of three types of zinc(II) alkanoates (Zn(C-n)(2), ZnNa2(C-n)(4) and ZaK(2)(C-n)(4), C-n = CH3(CH2)(n-2)COO-, n = 8-18) were investigated by Fourier transform infrared spectroscopy (FTIR) and powder X-ray diffraction (PXRD) to aid the study of degradation phenomena in oil paint. Each type of complex forms a homologous series in the studied chain length range. For (Zn(C-n)(2) and ZnNa2(C-n)(4), these homologous series indicate that the long-chain complexes have structures highly similar to those published for short-chain single-crystal analogs. Moreover, we introduce a chain tilt factor F-tilt to derive information about alkanoate chain angles from highly accurate PXRD long spacing values. The complex ZnK2(C-n)(4) has not been reported before. It consists of metal sheets containing tetrahedrally coordinated Zn atoms and octahedrally coordinated K atoms bridged by effectively monodentate carboxylate groups, and alkanoate chains that are tilted relative to the long axis.
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| 35. |
- Hussami, Linda, et al.
(författare)
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Polyhedral carbon nanofoams with minimum surface area partitions produced using silica nanofoams as templates
- 2010
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Ingår i: Carbon. - : Elsevier BV. - 0008-6223 .- 1873-3891. ; 48:11, s. 3121-3130
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Tidskriftsartikel (refereegranskat)abstract
- Polyhedral silica nanofoam (PNF-SiO2) analogues of dry soap froths with minimal surface area were used as templates for making polyhedral carbon nanofoams (PNF-C). Furfuryl alcohol or triblock copolymers were used as carbon sources. The volume of carbon precursor relative to the internal pore volume of PNF-SiO2's was systematically varied between 50% and 100% in order to investigate the effect of filling fraction on internal structure of the corresponding PNF-C's. Transmission electron microscopy, small-angle X-ray scattering and nitrogen physisorption were used to characterize the samples. To aid the interpretation of the experimental data, a model for X-ray scattering from spherical shells was used to approximate scattering from the polyhedral foam cells. PNF-C's cast from the PNF-SiO2's, displayed the characteristic Plateau borders of minimal surface area foams defining interconnected, slit-like pore systems at all filling fractions. At relatively high filling fractions, inverse foam structures were obtained with the slit-like pores systems interpenetrating aggregated, close-packed, relatively low density polyhedral carbon nanoparticles co-joined by carbon struts. At relatively low filling fractions, polyhedral carbon nanofoams with relatively thin, fused double-wall structures and interconnected polyhedral pore systems were obtained.
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| 36. |
- Hussami, Linda, et al.
(författare)
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Study of [Dy(eta(6)-p-xylene)(GaCl4)(3)]-incorporated polyhedral silica nanofoam
- 2010
-
Ingår i: Microporous and Mesoporous Materials. - : Elsevier BV. - 1387-1811 .- 1873-3093. ; 132:3, s. 480-486
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Tidskriftsartikel (refereegranskat)abstract
- Preparation and characterization of organometallic dysprosium complex embedded polyhedral silica nanofoam (PNE-SiO2) is reported. The nanoporous solid was obtained via a sol-gel process involving precipitation of polymer micelles, hydrolysis and condensation of silica by swelling of triblock copolymer template micelles of PEO-PPO-PEO at acidic pH using high oil concentration and fast stirring. Metal-complex incorporation was performed via wet impregnation (WI) at higher temperature, where the dysprosium complex is chemically bound to the silanol groups of the silica foam surface. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and small angle X-ray scattering (SAXS) revealed that the particles of the organometallic complex are evenly distributed on the walls of the polyhedral cells, while nitrogen adsorption/desorption measurements (BET) verified that the characteristic meso- and macrocell structure of PNE-SiO2 composed of polyhedral cells of silica joined at mesosized windows are preserved also after incorporation.
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| 37. |
- Kharkov, Boris B., et al.
(författare)
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Phase Transitions and Chain Dynamics of Surfactants Intercalated into the Galleries of Naturally Occurring Clay Mineral Magadiite
- 2014
-
Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 30:26, s. 7859-7866
-
Tidskriftsartikel (refereegranskat)abstract
- We investigate conformational dynamics and phase transitions of surfactant molecules confined in the layered galleries of the organo-modified, natural polysilicate clay, magadiite. We have shown that our approach to studying this class of materials is capable of delivering detailed information on the molecular mobility of the confined molecules. From the analysis of the measured heteronuclear dipolar couplings, the orientational order parameters of the C-H bonds along the hydrocarbon chain have been determined. Three phases have been observed in the nanocomposite, characterized by distinct dynamical states of the surfactant. At room temperature, restricted mobility of the molecules led to the adoption of an essentially all-trans conformation by the chains. This behavior can be described by a model incorporating small-angle wobbling around the long molecular axes of the chains. Upon heating, dynamic transformation takes place, resulting in a rotator type solid phase where molecules in extended all-trans conformations undergo fast and unrestricted rotation about their respective symmetry axes. The second phase transition is associated with chain melting and the onset of translational dynamics and results in an essentially liquid-crystalline-like state of the organic component. The mobility of the surfactant is one of the key factors facilitating the efficient penetration of macromolecules in the process of preparing of polymer/organoclay nanocomposites. The exploration of dynamic properties of the fimctionalizing organic layer should provide important input into the improved design of new organic-inorganic hybrid materials.
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| 38. |
- Mille, C., et al.
(författare)
-
3-D chiral photonic crystals replicated from butterfly wing scales
- 2011
-
Ingår i: Materials Research Society Symposium Proceedings. - : Springer Science and Business Media LLC. - 9781627482103 ; , s. 7-12
-
Konferensbidrag (refereegranskat)abstract
- Three dimensional silica photonic crystals with the gyroid minimal surface structure have been synthesized using the butterfly Callophrys rubi as a template. The replicas are synthesized with a high degree of fidelity, which is confirmed by the spectral and morphological characterization. Further, the material is shown to be optically active.
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| 39. |
- Mille, Christian, et al.
(författare)
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3D titania photonic crystals replicated from gyroid structures in butterfly wing scales : Approaching full band gaps at visible wavelengths
- 2013
-
Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 3:9, s. 3109-3117
-
Tidskriftsartikel (refereegranskat)abstract
- 3D titania photonic crystals are replicated from single gyroid structures found in the butterfly Callophrys rubi. Photonic crystals were characterised using SEM imaging, X-ray and Raman scattering and reflection spectroscopy. The overall symmetry and topology of the original single gyroid structures is replicated with high fidelity. Titania replicas display photonic responses that are thermal history dependent. Replicas treated at 700 °C, show up to 96% reflectivity at ∼505 nm, while at lower and higher treatment temperatures the photonic response was not as pronounced. Simulated band structures fitted to the observed spectral reflectivity data constrain the solid volume fractions and dielectric constants of the replicas. The titania photonic crystals were also found to be optically active, with both left- and right-handed single gyroids contributing to the chiral response. The 3D titania photonic crystals replicated here have nearly complete overlapping of partial band gaps, strongly suggesting that materials with full photonic band gaps are experimentally within reach using the general replication approach reported here.
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| 40. |
- Mille, Christian, et al.
(författare)
-
A structural and thermal conductivity study of highly porous, hierarchical polyhedral nanofoam shells made by condensing silica in microemulsion films on the surface of emulsified oil drops
- 2013
-
Ingår i: Journal of Materials Chemistry A. - London : Royal Society of Chemistry (RSC). - 2050-7488 .- 2050-7496. ; 1:5, s. 1849-1859
-
Tidskriftsartikel (refereegranskat)abstract
- Light-weight solid foams are utilized in applications such as packaging and insulation mainly due to their intrinsically high porosity, low relative density and associated mechanical and transport properties. Here hollow core spherical shells are prepared with walls made of a polyhedral silica nanofoam with open cells. A microemulsion film at the oil-water interface of oil droplets is used as a soft structural template for the condensation of soluble silica species. The microemulsion sets the length scale of the monodisperse silica nanofoam cells, and the emulsion droplets set the micron-scale dimensions of the polydisperse spherical shells. Porosity is achieved by removing the templates and oils, leaving pure low-density silica. This results in a hierarchically structured, highly porous shell foam material that packs into beds with a measured porosity of approximately 97.3%, well into the range of silica aerogels. Using a combination of electron microscopy, small-angle synchrotron X-ray diffraction and nitrogen physisorption, an accurate structural model for the nanofoam shells is constructed. The material is shown to be comprised of open-cell foams that are structurally analogous to dry polyhedral soap froths having minimal surface partitions, and Plateau boundaries. The primary polyhedral nanofoam cells are 30 nm in diameter connected by 7 nm cylindrical windows. These nanofoams form spherical monolithic shells with volume average mean diameter of 41 microns and shell thickness of 0.7 microns. Simple models for the thermal conductivity of these nanofoam shell materials are constructed that include accounting for the nanoscale effects on gaseous and solid thermal conductivity. These are compared to the measured value of 0.041 W m-1 K-1. These materials represent new structures in the family of self-assembled, highly porous silica materials and are potentially useful in packaging and insulation and other applications due to their light weight and/or intrinsically low thermal conductivity and associated mechanical and transport properties.
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| 41. |
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| 42. |
- Mille, C. B., et al.
(författare)
-
Structuring membrane proteins as tools in material science
- 2010
-
Ingår i: Nanotechnology 2010. - 9781439834152 ; , s. 246-249
-
Konferensbidrag (refereegranskat)abstract
- Integral membrane proteins are interesting from a material science point of view due to their wide variety of functions and the possibility to create a functional barrier or carrier system. By using the same mols. found in nature, the structure and properties can be mimicked and utilized in designed materials. Two membrane proteins derived from yeast, Yop1p and Rtn1p, have been engineered, heterogeneously expressed and purified using a GFP-fusion platform. Both proteins are membrane spanning and can be found in all eukaryotes in which they are used for structural control of the endoplasmatic network. Yop1p and Rtn1p have previously been shown to induce tubules in lipid vesicles and we have seen that by altering the concn. of structuring protein as well as the shape of the lipids, the vesicle morphol. can be controlled.
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| 43. |
- Mille, Christian, et al.
(författare)
-
Inorganic chiral 3-D photonic crystals with bicontinuous gyroid structure replicated from butterfly wing scales
- 2011
-
Ingår i: Chemical Communications. - : Royal Society of Chemistry (RSC). - 1359-7345 .- 1364-548X. ; 47:35, s. 9873-9875
-
Tidskriftsartikel (refereegranskat)abstract
- Three dimensional silica photonic crystals with the gyroid minimal surface structure have been synthesized. The butterfly Callophrys rubi was used as a biotemplate. This material represents a significant addition to the small family of synthetic bicontinuous photonic crystals.
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| 44. |
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| 45. |
- Mirnaya, TA, et al.
(författare)
-
Phase diagrams and optical properties of binary liquid crystalline systems of cobalt (II) caprylate with lithium and lead caplylates
- 2011
-
Ingår i: Journal of Non-Crystalline Solids. - : Elsevier BV. - 0022-3093 .- 1873-4812. ; 357:16-17, s. 3053-3057
-
Tidskriftsartikel (refereegranskat)abstract
- The concentration and temperature ranges of liquid crystal and glass formation in binary systems of cobalt (II) caprylate with either lithium or lead caplylates have been studied by differential thermal analysis and optical polarization microscopy. Absorption spectra of Co(II) cations in mesophases and glasses of these binary caprylate systems have been analyzed as a function of temperature and composition to get information on the coordination of Co(II) ions. For the binary system of lead-cobalt caprylate. we found that the Co(II) ions are octahedrally coordinated over the range of temperatures and compositions studied, whereas in the binary lithium-lead caprylate system. the Co(II) ions can exist in both octahedral and tetrahedral coordination depending on composition and temperature. Thermochromic behavior was observed for all compositions studied here, from blue to violet and pink, depending on the composition and temperature of the system studied. An unusual increase of optical density with decreased Co(II) ion concentration has been observed for the Co-Li caprylate binary system up to 50 mol%. An increasingly ionic Co(II) coordination environment as Li ion concentration increases facilitates a concomitant increase in the proportion of more optically dense tetrahedrally coordinated Co(II) ions.
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| 46. |
- Oliynyk, Vitaliy, et al.
(författare)
-
Selective and ATP-driven transport of ions across supported membranes into nanoporous carriers using gramicidin A and ATP synthase
- 2013
-
Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 15:8, s. 2733-2740
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Tidskriftsartikel (refereegranskat)abstract
- We report a robust and versatile membrane protein based system for selective uptake and release of ions from nanoporous particles sealed with ion-tight lipid bilayers of various compositions that is driven by the addition of ATP or a chemical potential gradient. We have successfully incorporated both a passive ion channel-type peptide (gramicidin A) and a more complex primary sodium ion transporter (ATP synthase) into the supported lipid bilayers on solid nanoporous silica particles. Protein-mediated controlled release/uptake of sodium ions across the ion-tight lipid bilayer seal from or into the nanoporous silica carrier was imaged in real time using a confocal laser scanning microscope and the intensity changes were quantified. ATP-driven transport of sodium ions across the supported lipid bilayer against a chemical gradient was demonstrated. The possibility of designing durable carriers with tight lipid membranes, containing membrane proteins for selective ion uptake and release, offers new possibilities for functional studies of single or cascading membrane protein systems and could also be used as biomimetic microreactors for controlled synthesis of inorganic multicomponent materials.
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| 47. |
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| 48. |
- Pink, David A., et al.
(författare)
-
Modeling the solid-liquid phase transition in saturated triglycerides
- 2010
-
Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 132:5, s. 054502/1-054502/11
-
Tidskriftsartikel (refereegranskat)abstract
- We investigated theor. two competing published scenarios for the melting transition of the triglyceride trilaurin (TL): those of (1) Corkery et al., in which the av. state of each TL mol. in the liq. phase is a discotic "Y" conformer whose three chains are dynamically twisted, with an av. angle of ∌120° between them, and those of (2) Cebula et al., in which the liq.-state conformation of the TL mol. in the liq. phase is a nematic h*-conformer whose three chains are in a modified "chair" conformation. We developed two competing models for the two scenarios, in which TL mols. are in a nematic compact-chair (or "h") conformation, with extended, possibly all-trans, chains at low-temps., and in either a Y conformation or an h* conformation in the liq. state at temps. higher than the phase-transition temp., T* = 319 K. We defined an h-Y model as a realization of the proposal of R. Corkery et al. (2007), and explored its predictions by mapping it onto an Ising model in a temp.-dependent field, performing a mean-field approxn., and calcg. the transition enthalpy ΔH. We found that the most plausible realization of the h-Y model, as applied to the solid-liq. phase transition in TL, and likely to all satd. triglycerides, gave a value of ΔH in reasonable agreement with the expt. We then defined an alternative h-h* model as a realization of the proposal of D. J. Cebula et al. (1992), in which the liq. phase exhibits an av. symmetry breaking similar to an h conformation, but with twisted chains, to see whether it could describe the TL phase transition. The h-h* model gave a value of ΔH that was too small by a factor of ∌3-4. We also predicted the temp. dependence of the 1132 cm-1 Raman band for both models, and performed measurements of the ratios of three TL Raman bands in the temp. range of -20° ≀ T ≀ 90°. The exptl. results were in accord with the predictions of the h-Y model and support the proposal of that the liq. state is made up of mols. that are each, on av., in a Y conformation. Finally, we carried out computer simulations of minimal-model TLs in the liq. phase, and concluded that although the individual TL mols. are, on av., Y conformers, long-range discotic order is unlikely to exist.
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| 49. |
- Riedlinger, Michael D., et al.
(författare)
-
Cosmetic skincare applications employing mineral-derived tubules for controlled release
- 2005
-
Patent (populärvet., debatt m.m.)abstract
- Compositions and methods pertaining to the topical treatment of skin are disclosed. The present invention relates to topical compositions for regulating the condition of skin, especially for regulating visible and/or tactile discontinuities in skin associated with skin aging, environmental affects and the like. One embodiment of the present invention relates to improving skin with compositions containing one or more non-volatile, slowly absorbed, liquid or semi-liquid organic substances (active agents) via controlled release of active agents associated with mineral-derived tubules such as halloysite nanotubules. For example, the active agents, in the form of organic substances may include vitamin compounds and glycerin, among others.
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| 50. |
- Vargas-Florencia, Dulce, et al.
(författare)
-
Pore morphology and interconnectivity in a mesoporous/macroporous polyhedral silica foam material
- 2008
-
Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 24:9, s. 4827-4832
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The pore system of a highly swollen, block-copolymer-templated, polyhedral silica foam material is investigated by a combination of transmission electron microscopy, nitrogen sorption, and NMR cryoporometry. The adsorption-desorption hysteresis and melting-freezing hysteresis data recorded by the respective methods provide pore Volume and access channel sizes that virtually coincide for the two used methods. This provides a consistent picture where polyhedral foam cells of 60-70 nm diameter are interconnected by cylindrical access channels with several characteristic sizes for the latter.
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