Diffusion coefficients of sodium dodecyl sulfate in water swollen cross-linked polyacrylamide membranes

Abstract

Diffusion of aqueous sodium dodecyl sulfate (SDS) across cross-linked polyacrylamide hydrogel membranes has been studied by electrical conductivity measurements. Initial rapid sorption of SDS (as unimer) into the membranes is observed. The effect of SDS concentration, and of cross-linker fraction on the degree of swelling of the gels is studied and associated with binding of the surfactant to the polymer, with surface bound water suggested to be involved in these interactions. Below the surfactant critical micelle concentration, volume collapse of less cross-linked membranes is observed, and associated with aggregate formation. Fluorescence measurements using pyrene as a probe show that micellar aggregates do not diffuse through the membrane, and only overall unimer diffusion is observed. The effect of cross-linking on the diffusion process is discussed.

Combined sorption/transport of sodium dodecyl sulfate and hydrochloric acid in a blend of cellulose acetate butyrate with cellulose acetate hydrogen phthalate

“…This method is applied to the study of diffusion of electrolytes in polymer membranes [13,14]. We are particularly interested in the behaviour of ionic surfactants, and we have previously studied the diffusion of the important anionic detergent sodium dodecyl sulfate (SDS) in poly(acrylamide) gels [15] and in cellulose ester membranes of differing degrees of hydrophobicity [11].…”

Electric field assisted transdermal drug delivery from salicylic acid-loaded polyacrylamide hydrogels

“…The diffusion coefficients of acetylsalicylic acid are 1.2 × 10 −7 and 8.5 × 10 −8 cm 2 /s for the cross-linking ratios (mol MBA /mol AAM ) of 0.0115 and 0.02305, respectively (Ferreira et al, 2001). Valento et al (2000) reported a similar effect of cross-linking ratio on the diffusion coefficients of sodium dodecyl sulfate, SDS (drug size ~ 20 Å) in waterswollen cross-linked polyacrylamide membranes in the absence of an electric field. The diffusion of SDS through polyacrylamide hydrogel was measured by using the cell that consists of two components filled with SDS solution and water, respectively.…”

“…The diffusion coefficient apparently decreases with increasing cross-link ratio due to a decreasing matrix pore size. The diffusion coefficients of sodium dodecyl sulfate are 0.5 × 10 −6 , 1.2 × 10 −6 , and 2.5 × 10 −6 cm 2 /s for cross-linking ratios (mol MBA /mol AAM ) of 0.032, 0.0032, and 0.0014, respectively (Valento et al, 2000).…”

“…This may originate from the lower potential to form interaction between PAAM hydrogel and the luteinizing hormone, and the higher diffusability of the drug through the abdominal hairless rat skin; thus a larger diffusion coefficient was obtained. In general, we may conclude that the diffusion coefficient of a drug in transdermal delivery system depends on several factors: the chemical composition of the drug, the molecular weight of the drug, and the size of the drug, the polymer matrix, the drug-matrix interaction, and the experimental set-up, as shown in Table 2 (Attwood et al, 1981;Chen & Chien, 1996;Valento et al, 2000;Ferreira et al, 2001;Vankov, 2004), and a further studied is needed.…”

Effect of Marangoni flow on subcooled pool boiling on micro-scale and macro-scale heaters in water and surfactant solutions

“…For surfactant solution @r=@T was taken from experimental r(C) measurements, Table 1, D is about 10 À10 m 2 /s, Valente et al [24].…”