Interaction of (hydroxypropyl) cellulose with anionic surfactants in dilute regime |
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Authors: | Ricardo M. de Martins Carolina A. da Silva Cristiane M. Becker Dimitrios Samios Marcelo Christoff Clara I. D. Bica |
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Affiliation: | 1. Instituto de Química-UFRGS, Av. Bento Gon?alves, 9500 C. P. 15003 CEP, 91501-970, Porto Alegre/RS, Brazil 2. FEPAM - Funda??o Estadual de Prote??o Ambiental Henrique Luis Roessler/RS Rua Carlos Chagas, 55 CEP 90030-020 Porto Alegre/RS, Brazil & UERGS, Unidade Bento Gon?alves, Av. Benjamin Constant, 229 CEP, 95700-000, Bento Gon?alves/RS, Brazil
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Abstract: | (Hydroxypropyl)cellulose (HPC) dilute aqueous solutions in the presence of sodium cholate (CS), sodium deoxycholate (DC), and sodium dodecylsulphate (SDS) were investigated. The hydrophobicity parameter (I 1/I 3) from fluorescence has shown a critical aggregation concentration (CAC) lower than the critical micellar concentration (CMC). One or two breakpoints were observed in the curve conductivity vs surfactant concentration. The thermodynamic parameters of aggregation (, and ) and the degree of counterion dissociation were calculated. Evidences for the secondary aggregation of CS/water system were found. The relative viscosity increases for HPC/bile salt solutions only at high surfactant concentrations, whereas for HPC/SDS, it passes through a maximum. The cloud points of both HPC/bile salt solutions at higher surfactant concentrations reach a temperature plateau value around 324 K, while for HPC/SDS, it exceeds 373 K at low SDS concentrations. Dynamic light scattering has demonstrated that the surfactants bind to HPC already at concentrations lower than CAC.Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users. |
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Keywords: | (hydroxypropyl)cellulose Bile salts Aggregation Fluorescence Light scattering |
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