Title: Effect of varying nonwoven cotton substrate and the properties of the surfactant solution upon the adsorption of aqueous solutions of alkyl-dimethyl-benzyl-ammonium chloride Authors
Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: January 18, 2011
Publication Date: April 25, 2011
Citation: Slopek, R.P., Condon, B.D., Sawhney, A.P., Reynolds, M.L., Allen Jr, H.C. 2011. Effect of varying nonwoven cotton substrate and the properties of the surfactant solution upon the adsorption of aqueous solutions of alkyl-dimethyl-benzyl-ammonium chloride. National Cotton Council Beltwide Cotton Conference. 1461-1466. Interpretive Summary: In textile processing, specifically the processing of cotton goods, surfactants are commonly used to enhance wettability, fabric softness, and dye adsorption. Additional uses of surfactants in cotton processing include stabilization of dispersions for chemical treatments, imparting antimicrobial properties, and removing foreign matter and waxes from the finished fabric. Although there has been a significant amount of research in the area of surfactant adsorption on cellulose, only a few of these studies focused on cotton as the form of cellulose and those that have examined the adsorption of nonionic compounds on woven cotton fabrics that has undergone significant processing. The objective of this research is to generate information and improve the general understanding of the adsorption of cationic surfactants onto cotton nonwovens with varying surface characteristics. Specifically, this work will examine the adsorption of alkyl-dimethyl-benzyl-ammonium chloride (ADBAC), a cationic surfactant known to have antimicrobial properties, onto low-weight hydrophobic (unscoured/bleached) and hydrophilic (scoured/bleached) cotton nonwoven fabrics using the depletion method. ADBAC was readily shown to adsorb onto untreated greige, scoured, and scoured/bleached cotton nonwovens. Based on the preliminary results of this study, greige cotton nonwovens absorbed 2.8 times more ADBAC than bleach nonwovens and fabric that had been simply scoured adsorbed 1.4 times more ADBAC than cotton that had been scoured and bleached. The adsorption isotherms for ADBAC exhibited a similar trend for all of the cotton nonwovens investigated. Blending polyester with the cotton reduced the amount of ADBAC that was exhausted from the initial bath. The resulting data is expected to aid in the development new cotton nonwoven products, such as disposable antimicrobial cotton based wipes, and new surfactant formulations for specifically designed for use on cotton fabrics.
Technical Abstract: The adsorption of alkyl-dimethyl-benzyl-ammonium chloride (ADBAC), a cationic surfactant commonly employed as an antimicrobial agent, on greige, alkaline scoured, and bleached nonwoven cotton fabrics was investigated at varying surfactant concentrations and liquor ratios using UV-vis absorption spectroscopy. The results show that greige cotton nonwovens adsorb roughly three times more ADBAC in aqueous solution than bleached cotton and two times more than scoured cotton nonwovens of similar weight and structure. At a constant ADBAC concentration of 0.625 g/L, the rate of surfactant adsorption approached equilibrium after 35 minutes in all fabrics studied. Increasing the surfactant concentration increased the total mass of ADBAC exhausted onto the cotton fabrics at equilibrium. Adsorption of ADBAC on cotton fabrics can be attributed to solution physical entrapment, hydrophobic interaction, electrostatic interactions, and dispersion forces. Polyester fiber was blended with greige and bleached cotton fibers to further elucidate the adsorption of ADBAC on cotton. A linear decrease in the amount of surfactant exhausted from the solution was observed as the amount of polyester added to the blend was increased. This result indicates that the adsorption of ADBAC on cotton fabrics is primarily an effect of surface interactions of the cotton fiber with the surfactant molecules rather than absorption via bulk entrapment. The information obtained in this work can be used in the development of a cotton based antimicrobial wipe.