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P123
Pluronic P123 is a symmetric triblock copolymer comprising poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) in an alternating linear fashion, PEO-PPO-PEO. The unique characteristic of PPO block, which is hydrophobic at temperatures above 288 K and is soluble in water at temperatures below 288 K, leads to the formation of micelle consisting of PEO-PPO-PEO triblock copolymers. Some studies report that the hydrophobic core contains PPO block, and a hydrophilic corona consists of PEO block. In 30wt% aqueous solution Pluronic P123 forms a cubic gel phase. The nominal chemical formula of P123 is HO(CH2CH2O)20(CH2CH(CH3)O)70(CH2CH2O)20H, which corresponds to a molecular weight of around 5800 g/mol. Triblock copolymers based on PEO-PPO-PEO chains are known generically as poloxamer. Poloxamers have behaviors similar to those of hydrocarbon surfactants, and will form micelles A micelle () or micella () ( or micellae, respectively) is an aggregate (or supramolecular assembly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Santa Barbara Amorphous-15
SBA-15, an acronym for Santa Barbara Amorphous-15, is a silica-based ordered mesoporous material that was first synthesized by researchers at the university of California Santa Barbra in 1998. This material proved important for scientists in various fields such as material sciences, drug delivery, catalysis, fuel cells and many other due to its desirable properties and ease of production. Synthesis procedure The procedure is a typical Liquid-Crystal templating that consists of three steps: # Solution preparation — P123, Pluronic P123 is dissolved in an acidic solution of water at specific molar ratios and the silica precursor typically Tetraethyl orthosilicate, TEOS or Tetramethyl orthosilicate, TMOS (sometimes EGMS) is added and mixed in for some time. # Hydrothermal treatment — The solution is sealed in a container and subjected to a temperature T1 for about 24 hours and then a higher temp T2 for 48 hours. # Washing and calcination — The gel obtained from the previous ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Poloxamer
Poloxamers are nonionic triblock copolymers composed of a central hydrophobic chain of polyoxypropylene (poly(propylene oxide)) flanked by two hydrophilic chains of polyoxyethylene (poly(ethylene oxide)). The word was coined by BASF inventor, Irving Schmolka, who received the patent for these materials in 1973. Poloxamers are also known by the trade names Pluronic, Kolliphor (pharma grade), and Synperonic. Because the lengths of the polymer blocks can be customized, many different poloxamers exist that have slightly different properties. For the generic term ''poloxamer'', these copolymers are commonly named with the letter ''P'' (for poloxamer) followed by three digits: the first two digits multiplied by 100 give the approximate molecular mass of the polyoxypropylene core, and the last digit multiplied by 10 gives the percentage polyoxyethylene content (e.g. P407 = poloxamer with a polyoxypropylene molecular mass of 4000 g/mol and a 70% polyoxyethylene content). For the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethylene Oxide
Ethylene oxide is an organic compound with the chemical formula, formula . It is a cyclic ether and the simplest epoxide: a three-membered ring (chemistry), ring consisting of one oxygen atom and two carbon atoms. Ethylene oxide is a colorless and flammable gas with a faintly sweet odor. Because it is a strained ring, ethylene oxide easily participates in a number of addition reactions that result in ring-opening. Ethylene oxide is isomeric with acetaldehyde and with vinyl alcohol. Ethylene oxide is industrially produced by oxidation of ethylene in the presence of a silver catalyst. The reactivity that is responsible for many of ethylene oxide's hazards also makes it useful. Although too dangerous for direct household use and generally unfamiliar to consumers, ethylene oxide is used for making many consumer products as well as non-consumer chemicals and intermediates. These products include detergents, thickeners, solvents, plastics, and various organic chemicals such as ethylen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Propylene Oxide
Propylene oxide is an epoxide with the molecular formula C3H6O. This colourless volatile liquid with an odour similar to ether, is produced on a large scale industrially. Its major application is its use for the production of polyether polyols for use in making polyurethane plastics. It is a chiral epoxide, although it is commonly used as a racemic mixture. This compound is sometimes called 1,2-propylene oxide to distinguish it from its isomer 1,3-propylene oxide, better known as oxetane. Production Industrial production of propylene oxide starts from propylene. Two general approaches are employed, one involving chlorohydrin formation and the other involving oxidation. In 2005, about half of the world production was through chlorohydrin technology and one half via oxidation routes. The latter approach is growing in importance. Chlorohydrin route The traditional route proceeds via the conversion of propylene to propylene chlorohydrin according to the following simplified sch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrophobic
In chemistry, hydrophobicity is the chemical property of a molecule (called a hydrophobe) that is seemingly repelled from a mass of water. In contrast, hydrophiles are attracted to water. Hydrophobic molecules tend to be nonpolar and, thus, prefer other neutral molecules and nonpolar solvents. Because water molecules are polar, hydrophobes do not dissolve well among them. Hydrophobic molecules in water often cluster together, forming micelles. Water on hydrophobic surfaces will exhibit a high contact angle. Examples of hydrophobic molecules include the alkanes, oils, fats, and greasy substances in general. Hydrophobic materials are used for oil removal from water, the management of oil spills, and chemical separation processes to remove non-polar substances from polar compounds. The term ''hydrophobic''—which comes from the Ancient Greek (), "having a fear of water", constructed Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon. revised and augmented ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micelle
A micelle () or micella () ( or micellae, respectively) is an aggregate (or supramolecular assembly) of surfactant amphipathic lipid molecules dispersed in a liquid, forming a colloidal suspension (also known as associated colloidal system). A typical micelle in water forms an aggregate, with the hydrophilic "head" regions in contact with surrounding solvent, sequestering the hydrophobic single-tail regions in the micelle centre. This phase is caused by the packing behavior of single-tail lipids in a bilayer. The difficulty in filling the volume of the interior of a bilayer, while accommodating the area per head group forced on the molecule by the hydration of the lipid head group, leads to the formation of the micelle. This type of micelle is known as a normal-phase micelle (or oil-in-water micelle). Inverse micelles have the head groups at the centre with the tails extending out (or water-in-oil micelle). Micelles are approximately spherical in shape. Other shapes, such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surfactants
Surfactants are chemical compounds that decrease the surface tension or interfacial tension between two liquids, a liquid and a gas, or a liquid and a solid. The word ''surfactant'' is a blend of "surface-active agent", coined in 1950. As they consist of a water-repellent and a water-attracting part, they enable water and oil to mix; they can form foam and facilitate the detachment of dirt. Surfactants are among the most widespread and commercially important chemicals. Private households as well as many industries use them in large quantities as detergents and cleaning agents, but also for example as emulsifiers, wetting agents, foaming agents, antistatic additives, or dispersants. Surfactants occur naturally in traditional plant-based detergents, e.g. horse chestnuts or soap nuts; they can also be found in the secretions of some caterpillars. Today one of the most commonly used anionic surfactants, linear alkylbenzene sulfates (LAS), are produced from petroleum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micelles
A micelle () or micella () ( or micellae, respectively) is an aggregate (or supramolecular assembly) of surfactant amphipathic lipid molecules dispersed in a liquid, forming a colloidal suspension (also known as associated colloidal system). A typical micelle in water forms an aggregate, with the hydrophilic "head" regions in contact with surrounding solvent, sequestering the hydrophobic single-tail regions in the micelle centre. This phase is caused by the packing behavior of single-tail lipids in a bilayer. The difficulty in filling the volume of the interior of a bilayer, while accommodating the area per head group forced on the molecule by the hydration of the lipid head group, leads to the formation of the micelle. This type of micelle is known as a normal-phase micelle (or oil-in-water micelle). Inverse micelles have the head groups at the centre with the tails extending out (or water-in-oil micelle). Micelles are approximately spherical in shape. Other shapes, such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FDU Materials
FDU Materials are a class of regularly structured mesoporous organic materials first synthesized at Fudan University in Shanghai, China (hence FDU). FDU-14 -15 and -16 are formed by polymerizing resol around a lyotropic liquid crystal template and then removing the template by calcination Calcination is thermal treatment of a solid chemical compound (e.g. mixed carbonate ores) whereby the compound is raised to high temperature without melting under restricted supply of ambient oxygen (i.e. gaseous O2 fraction of air), generally f .... Notes *Denyuan Zhao et al. '' Angew. Chem. Int. Ed.'' 2005, 44, 7053 {{material-stub Materials ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
