39 research outputs found
BaRTv1.0:an improved barley reference transcript dataset to determine accurate changes in the barley transcriptome using RNA-seq
The cell-wide web coordinates cellular processes by directing site-specific Ca²⁺ flux across cytoplasmic nanocourses
A novel approach to genome-wide association analysis identifies genetic associations with primary biliary cholangitis and primary sclerosing cholangitis in Polish patients
Micellization of water-soluble complex salts of an ionic surfactant with hairy polymeric counterions
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)For ionic surfactants in general, a change from simple to polymeric counterions leads to increasing attraction between micelles, condensing them in a concentrated phase. In the present study, two novel "complex salts" were prepared in which the cationic surfactant hexadecyltrimethylammonium was neutralized by two different copolyions, both having poly(methacrylate) main chains randomly decorated with oligo(ethylene oxide) side chains. The presence of hydrophilic side chains in the polyion backbone is proposed as a strategy to stabilize the complex salt aggregates in aqueous solutions and prevent them from separating out in a concentrated phase. Surface tension experiments reveal that the complex salts form soluble nano-aggregates by surfactant ion self-assembly at a distinct critical micellization concentration (cmc), similar to the micellization of a conventional ionic surfactant. This is the first time that cmc values have been determined for complex salts in the absence of all other ions. The physicochemical nature of the aggregates formed was investigated by dynamic light scattering, nuclear magnetic resonance self-diffusion measurements and steady-state fluorescence spectroscopy. Much larger aggregates are formed when the temperature is increased, but the small aggregates reform at room temperature, suggesting that the soluble aggregates are equilibrium structures, much like the micelles of conventional surfactants.92515526Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Swedish Research Council (VR)Linnaeus grant Organizing Molecular Matter (OMM) through VR [239-2009-6749]Knut and Alice Wallenberg FoundationCrafoord FoundationFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Linnaeus grant Organizing Molecular Matter (OMM) through VR [239-2009-6749