A systematic study of collisions between surfactant-free organic drops in aqueous electrolyte solutions reveals the threshold at which continuum models provide a complete description of thin-film interactions. For collision velocities above ~1 μm/s, continuum models of hydrodynamics and surface forces provide a complete description of the interaction, despite the absence of surfactant. This inc...

We report in situ spectroscopic measurements monitoring the adsorption of a series of carboxylate surfactants onto the surface of the semisoluble, ionic solid fluorite (CaF2). We employ the surface-specific technique, vibrational sum-frequency spectroscopy (VSFS), to examine the effect that surfactant adsorption has on the bonding interactions and orientation of interfacial water molecules thro...

The function of the lung is dependent upon differentiation and proliferation of respiratory epithelial cells and the synthesis/secretion of surfactant lipids and proteins into air space. During the respiratory inflammatory response, cytokines produced by macrophages and epithelial cells in the respiratory system have significant influence on surfactant protein homeostasis. We report here that a...

Rationally encoding molecular interactions that can control the assembly structure and functional expression in a solution of conjugated polymers hold great potential for enabling optimal organic optoelectronic and sensory materials. In this work, we show that thermally-controlled and surfactant-guided assembly of water-soluble conjugated polymers in aqueous solution is a simple and effective s...

Synergy and antagonism between sugar-based surfactants, a group of environmentally benign surfactants, and cationic surfactants and nonionic ethoxylated surfactants have been investigated in this study with solids which adsorbs only one or other when presented alone. Sugar-based n-dodecyl-β-D-maltoside (DM) does not adsorb on silica by itself. However, in mixtures with cationic dodecyltrimethyl...

We have developed a new technique (based on our Cartesian-representation method) to describe hydrodynamic interactions of a spherical particle with an undeformable planar fluid-fluid interface under creeping-flow conditions. The interface can be either surfactant-free or covered with an incompressible surfactant monolayer. We consider the effect of surface incompressibility and surface viscosit...

Trypsin-dissociated HeLa and human amnion cells were employed to investigate the effects of an anionic, a cationic, and a non-ionic surfactant on cell reaggregation. All the surfactants inhibited the reaggregation process, the effect increasing with surfactant concentration, and becoming significant at concentrations of about 10(-6) M for the anionic surfactant and about 10(-5) M for the others...

Vibrational sum frequency generation spectroscopy is used to study the interactions of the charged soluble organic surfactant sodium dodecyl sulfate (SDS) with an insoluble 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) monolayer at the air-aqueous interface. Results indicate that the surfactant species compete for surface sites in the mixed system, with a lower monolayer number density of ...

In order to know the influence of the surface characteristics and the chain properties on the adsorption of amphiphilic molecules onto polystyrene latex, a set of experiments to study the adsorption of ionic surfactants, nonionic surfactants and an amphiphilic synthetic peptide on different latex dispersions was performed. The adsorbed amount versus the equilibrium surfactant concentration was ...

A chiral amino acid-based monomeric and polymeric surfactant, sodium oleyl-L-leucylvalinate) (L-SOLV) and poly(sodium oleyl-L-leucylvalinate) (poly-L-SOLV) were synthesized and used for chiral separations in micellar electrokinetic chromatography (MEKC). Poly-L-SOLV was used successfully in the separation of various enantiomers of neutral, acidic, and basic analytes such as 1,1'-bi-2-napthol, 1...