Adsorption and Desorption of Ionic Surfactants

Abstract

Surfactants as organic compounds are widely used in the processes of textile finishing and care with regard to different variations and specific hydrophilic/hydrophobic character. Specific behaviour of these compounds is partly based on the adsorption process. In this study the adsorption and desorption of ionic surfactants have been studied upon the influence of fibre composition and surfactant ionogenity as well as variation of hydrophobic chain length and hydrophilic group in the molecule. Textile fibres were characterized through electrokinetic potential, sorption characteristics and swelling capacity expressed by moisture regain and water retention value (WRV). Different types of cationic and anionic surfactants were adsorbed on cotton, wool, polyester and polypropylene fibres at 20°C during 60 minutes. The quantity of adsorbed surfactants on textile fibres was determined by potentiometric titration. The textile fibres were centrifuged afterwards and the amount of surfactants was determined in the centrifugate, respectively. Drying followed at 60°C. The desorption of surfactants was performed at 20°C during 30 minutes. The results showed a correlation between amount of adsorbed, desorbed and residual surfactants and swelling capacity expressed through WRV.

From Raw to Finished Cotton—Characterization by Interface Phenomena

“…These phenomena occur at the solid-liquid interface, such as textile material and water solutions. Interface phenomena signifi cantly depend on the solid surface free energy and surface electrokinetic properties in water solutions, such as zeta potential (ZP) and a specifi c amount of surface charge [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. At the interface of electrically charged textile fi bers and an aqueous solution of electrolyte, surfactants or dyes, an electric double layer is set up, inducing the electrokinetic potential (ZP).…”

“…The ZP gives information about nature and dissociation of functional groups, hydrophilicity, or hydrophobicity of the fi ber surface as well as ions or water sorption and the portion of amorphous regions where the adsorption processes take place [2][3][4][5][8][9][10][11][12]. In general, specifi c adsorption of ions or dissociation of the surface groups in aqueous solution results with their surface charge, which depends on their molecular and supramolecular structure, swelling capacity, ionogenity, structure, and concentration of adsorbate [5,13]. These phenomena are crucial for textile dyeing and fi nishing as well as for textile care.…”

“…Changing the number of functional fi ber surface groups, for example, by blocking in dyeing and fi nishing processes, and their dissociation affect the distribution of the surface charge, surface free energy, and the thickness and distribution of the electric double layer, resulting in different fabric interface phenomena [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. When a drop of liquid is set on a solid surface, it creates a contact angle.…”

Wetting and wicking of hospital protective textiles

“…In general, specific adsorption of ions or dissociation of the surface groups in aqueous solution results with their surface charge. It depends on their molecular and supramolecular structure, swelling capacity, ionogenity, structure and concentration of adsorbate [13,[15][16][17][18]. Any change in the number of functional groups, e.g.…”

“…Any change in the number of functional groups, e.g. by blocking in dyeing and finishing processes, and their dissociation affect the distribution of surface charge, surface free energy as well as the thickness and distribution of the electric double layer results in different fabric interface phenomena [15][16][17][18][19][20][21][22][23].…”