Formação de multicamadas de polissacarídeos e proteína

In this work the formation of multilayers composed by carboxymethylcellulose (CMC), chitosane and bovine serum albumin (BSA) was studied by ellipsometry. First, the adsorption behavior of carboxymethylcellulose onto amino-terminated surfaces was investigated as a function of molecular weight and average degree of substitution of CMC. The influence of these parameters on the adsorbed amount of CMC onto amino-terminated substrates was absent. However, the interaction of CMC covered surfaces with chitosane and BSA was favored when the average degree of substitution of CMC was increased. The adsorption of BSA onto the polysaccharide systems was studied as a function of pH. At the isoelectric point of BSA a maximum in the adsorbed amount was found.

Estudo sobre a adsorção do fluido de perfuração salgado contendo polímeros sobre SiO2

Polysaccharide-based drilling fluids have been often applied in horizontal wells of petroleum reservoirs in Campos, Rio de Janeiro. The present study aimed to understand the mechanism of adsorption and desorption of the drill-in fluid, xanthan, modified starch and lubricant on SiO2 by means of ellipsometry. The effect of pH and brine on the mean thickness (D) of adsorbed layer was systematically investigated. The adsorption was mainly favored under alkaline conditions. A model has been proposed to explain this effect. The adsorption isotherms determined separately for xanthan and starch on SiO2 surfaces could be fitted with the Langmuir model, which yielded similar adsorption constant values.