Wetting of SiO2 surfaces by phospholipid dispersions Salay, Luiz Carlos; Carmona-Ribeiro, Ana Maria
Journal of adhesion science and technology,
19/1/1/, Volume:
13, Issue:
10
Journal Article, Conference Proceeding
Peer reviewed
Wetting of SiO
2
/Si/SiO
2
slides by phospholipid dispersions has been determined over a range of phospholipid concentrations and times of interaction between vesicles and the solid surface. Both ...advancing and receding dynamic contact angles () increased and
the contact angle hysteresis decreased as a function of the phospholipid concentration (or interaction time), attaining a maximum (a minimum). Maximization of both the advancing and receding contact angles and minimization of the contact angle hysteresis are associated with an increase in
the chemical homogeneity of the surface and one-bilayer deposition. Determination of contact angles is a Powerful, quick, and simple technique to establish experimental conditions for bilayer deposition on solid surfaces in general. This result may be of importance for further advancements
in rapidly developing research areas such as the design of biosensors, immunodiagnosis, and the development of biocompatible materials.
In this study, the influence of different ionic composition in aqueous solution on the minerals surface wettability was studied. The differences effect of monovalent ion and divalent ions onto the ...wettability alteration were studied. The anions were Cl- and SO42-. The SO42- could make the minerals surface more hydrophilic. Besides, the influence of NaCl, MgCl2, CaCl2, Na2SO4, K2SO4 and MgSO4 on the mineral wettability alteration were studied. The results indicated that divalent ions showed significant impact on the minerals wettability alteration, compared with monovalent ion. The reasons were due to the fact that divalent ions showed higher ions adsorption than monovalent ion, and divalent ions have higher effect on compressing the electric double layer. The static contact angle and dynamic contact angle were measured. Different heavy oils were studied, including heavy oil with 100 ppm, heavy oil, heavy oil without resins, heavy oil without asphaltenes. The results showed that the asphaltenes would make it difficult for the heavy oils to liberate from minerals, thus decreasing the oil drops contact angle. Then the resins would decrease the heavy oil contact angles. CaCl2/MgCl2 and K2SO4 have synergistic effect on the change of the minerals surface wettability. Atomic force microscope (AFM) measurement indicated that the ions would effectively decrease the interaction force on the surface of heavy oil-minerals, which was beneficial to the heavy oil liberation. The roughness measurement indicated that the different ions would effectively increase the minerals surface wettability.
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