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Query: UMLS:C0847097 (acidity)
 15,165 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The surface properties of poly(methyl methacrylate-co-n-butyl acrylate-co-cyclopentylstyryl polyhedral oligomeric silsesquioxane) (poly(MMA-co-BA-co-styryl-POSS)) were studied by means of inverse gas chromatography (IGC) using 10 non-polar and polar solvents as the probes. Thermodynamic parameters of adsorption, e.g., specific retention volume, the dispersive component of the surface free energy, the specific interaction contribution to the free energy of adsorption and the acid/base constants were obtained to investigate the interactions between the surfaces of the copolymers and different solvents. It was found that incorporation of styryl-POSS into polymer resulted in increasing interactions between polymers and solvents, dispersive component of surface free energy of polymer and acidity of the surfaces of the polymers. The more the styryl-POSS were embedded, the stronger the interaction between the polymer surface and solvent, the dispersive component of the surface free energy and the acidity of the polymer surface were.
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PMID:Surface characterization of poly(methyl methacrylate-co-n-butyl acrylate-co-cyclopentylstyryl-polyhedral oligomeric silsesquioxane) by inverse gas chromatography. 1646 Jul 44

The amphiphilic copolymer poly (styrene-co-methacrylic acid) (P (St-co-MAA)) with molar ratios of 6:4 and 7:3 self-assembled to form micelles. The polymeric micelles were used as pseudostationary phase (PSP) in micellar electrokinetic chromatography ( MEKC). Their physicochemical properties and MEKC performance were investigated as well in the present work. The critical micelle concentration ( CMC) , polarity, surface charge density and hydrodynamic diameter were used to characterize the solution physicochemical properties, while the methylene group selectivity was evaluated with n-alkylphenone homologous series. The time window and linear solvation energy relationship (LSER) analysis were used to characterize the MEKC retention behavior and the selectivity. All of these were compared with poly (methyl methacrylate-co-methacrylic acid) (P (MMA-co-MAA)) with the molar ratio of 7:3 and sodium dodecyl sulfate (SDS) micellar systems. The results showed that P ( St-co-MAA) system had the minimum CMC, the widest time window and the best methylene group selectivity. LSER analysis results showed that the hydrophobic effect was the most important interaction between solutes and PSPs, and the hydrogen-bonding acidity was the second significant factor on selectivity and MEKC retention behavior. P (St-co-MAA) system, especially with the molar ratio of 7 :3, had the highest effective parameter in LSER and showed a high separation selectivity of PSP.
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PMID:[Electrokinetic chromatographic properties of amphiphilic copolymer poly (styrene-co-methacrylic acid) self-assembled micelle pseudostationary phase]. 2629 11