The mechanical resistance of the stratum corneum, the outermost layer of skin, to deformation has been evaluated at different length scales using Atomic Force Microscopy. Nanomechanical surface mapping was first conducted using a sharp silicon tip and revealed that Young’s modulus of the stratum corneum varied over the surface with a mean value of about 0.4 GPa. Force indentation measurements showed permanent deformation of the skin surface only at high applied loads (above 4 μN). The latter effect was further demonstrated using nanomechanical imaging in which the obtained depth profiles clearly illustrate the effects of increased normal force on the elastic/plastic surface deformation. Force measurements utilizing the single hair fiber probe supported the nanoindentation results of the stratum corneum being highly elastic at the nanoscale, but revealed that the lateral scale of the deformation determines the effective elastic modulus.This result resolves the fact that the reported values in the literature vary greatly and will help to understand the biophysics of the interaction of razor cut hairs that curl back during growth and interact with the skin.

A new method to determine glass corrosion/etching is presented. The method enables a rapid screening of formulations in terms of their glass etching tendency as well as identification of the main components responsible for giving rise to the etching. Up to four formulations can be evaluated during one day. The high sensitivity of the QCM-D instrument enables measuring the etching of thicknesses less than one nm. Therefore, the technique can be used efficiently to screen components in the formulations and aid in the development phase of new tformatoptimised dishwash detergent formulations. In a planned work we will investigate the correlation between the etching rate of thin sputtered glass films at the surface of QCM-D crystals and good performance in a standardized dishwasher test using meltquenched glasses.

This review article will give a broad overview of the synthesized and characterised surfactants within the competence centre SNAP (Centre for Surfactants Based on Natural Products). The surfactants differ within their hydrophilic groups, hydrophobic groups as well as the linkage between these groups. The main focus was put on sugar-based surfactants and surfactants containing polyhydroxyl groups so this part will be the most extensive in the review. Interactions between surfactants and polymers have also been investigated and will be described in the final part of the review. SNAP resulted in the publication of 239 scientific articles and 22 PhD degrees.

Most modern surfactants are readily biodegradable and exhibit low toxicity in the aquatic environment, the two criteria for green surfactants. However the majority are synthesised from petroleum, so over the past decade the detergent industry has turned its attention to developing greener routes to create these surfactants via renewable building blocks. Surfactants from Renewable Resources presents the latest research and commercial applications in the emerging field of sustainable surfactant chemistry, with emphasis on production technology, surface chemical properties, biodegradability, ecotoxicity, market trends, economic viability and life-cycle analysis. Reviewing traditional sources for renewable surfactants as well as recent advances, this text focuses on techniques with potential for large scale application. Topics covered include: Renewable hydrophobes from natural fatty acids and forest industry by-products. Renewable hydrophiles from carbohydrates, amino acids and lactic acid. New ways of making renewable building blocks; ethylene from renewable resources and complex mixtures from waste biomass. Biosurfactants. Surface active polymers. This book is a valuable resource for industrial researchers in companies that produce and use surfactants, as well as academic researchers in surface and polymer chemistry, sustainable chemistry and chemical engineering.

An SPM has been used to measure frictional interactions between two crossed fibres for the first time. The preparation of the surfaces is briefly described, but the crucial element is that the fibre attached to the AFM cantilever is glued parallel to the long axis. The fibres consist of polyester and frictional forces were measured both in air and solutions of cationic surfactant C(14)TAB. The friction coefficients reduce markedly with increasing concentration of surfactant which is ascribed to the formation of a boundary lubricating film between the surfaces. On removal of the solution, the subsequent friction coefficient in air was reduced by more than a factor of two compared to its value before immersion.

From experimental surface tension data for water solutions of dodecyl-b-maltoside, C12M, and dodecyl penta (ethylene oxide), C12EO5, in the range below the CMC, the corresponding head group surface pressure functions vs. packing density have been derived. These functions are compared with theoretical expressions based on some different models of the mixed head group/water layer. Tentatively, we conclude that the two-dimensional hard fluid approach furnishes a convenient starting-point in order to account for the observed surface pressures of both the maltoside and EO head groups.

Small-angle neutron scattering (SANS) data for solutions containing a highly charged cationic polyelectrolyte and an anionic surfactant are presented. The scattering data were obtained in pure D2O, emphasizing the scattering from the polyelectrolyte, and in a H2O/D2O mixture that contrast matches the polyelectrolyte. In the absence of surfactant, a broad scattering peak due to the mesh size of the polyelectrolyte solution is the most characteristic feature. This peak moves to larger q-values (smaller distances) as the polyelectrolyte concentration is increased, as expected for a semidilute polyelectrolyte solution. Addition of a small amount of surfactant reduces and finally removes this peak. Instead a sharp diffraction peak appears at high q-values. This Bragg peak corresponds to a characteristic distance of 37-39 Å, and it is observed when either the polyelectrolyte or the surfactant is contrast matched by the solvent. Once this peak has appeared, its position does not change when the surfactant concentration is increased. The intensity of the peak grows, however, until a stoichiometric polyelectrolyte-surfactant complex has been formed. The Bragg peak remains in excess surfactant solution. These results are discussed in relation to the structure of the polyelectrolyte-surfactant aggregates and in connection with recent results from surface force and turbidity measurements using the same polyelectrolyte-surfactant pair.