Effect of SDS on human hair: Study on the molecular structure and morphology

Abstract

This paper presents a model study to understand the effect of surfactants on the physicochemical properties of human hair. FT-IR ATR spectroscopy has been employed to understand the chemical changes induced by sodium dodecyl sulfate (SDS) on human scalp hair. In particular, the SDS induced changes in the secondary structure of protein present in the outer protective layer of hair, i.e. cuticle, have been investigated. Conformational changes in the secondary structure of protein were studied by curve fitting of the amide I band after every phase of SDS treatment. It has been found that SDS brings rearrangements in the protein backbone conformations by transforming β -sheet structure to random coil and β -turn. Additionally, AFM and SEM studies were carried out to understand the morphological changes induced on the hair surface. SEM and AFM images demonstrated the rupture and partial erosion of cuticle sublayers.

Effects of surfactant adsorption on the wettability and friction of biomimetic surfaces

“…Adsorbed SDS molecules do provide considerable friction reductions compared to the water case, which is primarily due to enhanced electrostatic repulsion between the sliding surfaces. However, concentrated SDS solutions can cause damage to the hair cuticle surfaces in experiments, 108,109 which is not accounted for in our current simulations framework. This is likely to increase the surface roughness and remove some of the protective 18-MEA layer, which could perhaps play a more significant role than the enhanced electrostatic repulsion effect simulated here.…”

“…This observation is in contrast to previous experiments, which showed similar SDS adsorption on bleached and virgin hair at low concentrations, but higher surface coverages of SDS on bleached hair than virgin hair at high contractions. 23 This is likely because concentrated SDS solutions can cause significant damage to the hair cuticle, 108,109 which will inevitably change its surface properties. Such damage is likely to be more severe on bleached hair, where the protective 18-MEA layer has already been partially removed.…”

Effects of Surfactant Adsorption on the Wettability and Friction of Biomimetic Surfaces

“…Adsorbed SDS molecules do provide considerable friction reductions compared to the water case, which is primarily due to enhanced electrostatic repulsion between the sliding surfaces. However, concentrated SDS solutions can cause damage to the hair cuticle surfaces, 108,109 which is not accounted for in our current simulations framework. This is likely to increase the surface roughness and remove some of the protective 18-MEA layer, which could perhaps play a more significant role than the enhanced electrostatic repulsion effect simulated here.…”

UV–vis spectra as an alternative to the Lowry method for quantify hair damage induced by surfactants

“…[1,18]. Moreover, sodium dodecyl sulfate (SDS) causes hair cuticle protein denaturation [19] and extracts twice more proteins from hair than water [20].…”