Electric-Assisted Capillary Rise Adsorption of Polar and Nonpolar Solvents by Cellulose and Chitosan

Electric-assisted capillary rise adsorption of polar and nonpolar solvents by cellulose and chitosan was studied by employing an electrostatic generator to assist a common capillary rise wetting by taking the anode and cathode electrodes respectively linked to a metal tube charged with samples and the probe solvent. To vary the voltage at 0, 100, 200, and 300 V, respectively, the recorded dynamic adsorption results showed that the cellulose and chitosan both kept a stable adsorption of the nonpolar hexane and diiodomethane, obviously ignoring the voltage increase. Moreover, the hexane amount adsorbed by cellulose and chitosan is similar, while the diiodomethane amount was adsorbed to a greater amount by cellulose as compared with the chitosan corresponding to these two biomaterials-based nonpolar components, for example, greater for cellulose and smaller for chitosan. Results also showed that the adsorption of polar water and formamide was gradually increased with the voltage increase, especially for chitosan, to correspond to the polar component of these materials, for example, greater for chitosan and smaller for cellulose. These adsorption behaviors suggested that the application of an extra electric field can only enhance the adsorption of polar solvent, and the molecular structure, for exmaple, the β-(1-4)-linked d-glucosamine units of chitosan, has sensitive electric field responses in polar solvent adsorption as compared with those of the β(1-4)-linked d-glucose units of cellulose. The reason for the electric adsorption behaviors was known due to the presence of an extra electric-field-induced reduction of the total surface tension of solvent and mainly the polar component.