Biomedical surface science: Foundations to frontiers

Free energy was measured for the surface of regular aligned closest hexagonal packed −CF3 groups. n-Perfluoroeicosane was vapor deposited onto glass, which gave epitaxially grown single-like crystallites with their molecular axes perpendicular to the glass surface. The dynamic contact angle of water on its surface was 119°, which corresponds to a surface free energy of 6.7 mJ/m2. This value is considered to be the lowest surface free energy of any solid, based on the hexagonal closed alignment of −CF3 groups on the surface.

The Lowest Surface Free Energy Based on −CF3 Alignment

Acid—base interfacial interactions in aqueous media

Publisher Summary The chapter discusses the proteins at interfaces and aims to present protein adsorption and its ramifications, such as the effects of adsorption on conformation and reactivity from a fundamental physicochemical approach Although many proteins are very soluble in water, adsorption leads to stable monolayers that are extremely difficult to desorb Adsorption may be followed at fluid/fluid interfaces by measuring changes in interfacial pressure, potential, or viscosity, using spread monolayers for calibration purposes Before a protein molecule can adsorb and exert its influence at a phase boundary or take part in an interfacial reaction, it must arrive at the interface by a diffusion process At fluid/fluid interfaces, it is established that proteins lose their tertiary structure One of the advantages of the fluid/fluid type interface is that the distribution between adsorbed (trains) and displaced segments (loops) may be quantitatively studied by carrying out measurements with a film balance This approach has been used for spread monolayers of protein The high free energy of adsorption of proteins results in all segments being at the interface at low interfacial pressures The conformational changes that accompany desorption from an interface have direct bearing on the important subject of protein biosynthesis The chapter also discusses the equilibrium aspects of adsorption, reactions at interfaces, and proteins at interfaces in biological systems

Proteins at interfaces.

The molecular configuration of water adsorbed on a hydrophilic silicon oxide surface at room temperature has been determined as a function of relative humidity using attenuated total reflection (ATR)−infrared spectroscopy. A completely hydrogen-bonded icelike network of water grows up to three layers as the relative humidity increases from 0 to 30%. In the relative humidity range of 30−60%, the liquid water structure starts appearing while the icelike structure continues growing to saturation. The total thickness of the adsorbed layer increases only one molecular layer in this humidity range. Above 60% relative humidity, the liquid water configuration grows on top of the icelike layer. This structural evolution indicates that the outermost layer of the adsorbed water molecules undergoes transitions in equilibrium behavior as humidity varies. These transitions determine the shape of the adsorption isotherm curve. The structural transitions of the outermost adsorbed layer are accompanied by interfacial ener...

Evolution of the Adsorbed Water Layer Structure on Silicon Oxide at Room Temperature

Additivity of intermolecular forces at interfaces. i. determination of the contribution to surface and interfacial tensions of dispersion forces in various liquids1

Frederick M. Fowkes

Papers

Additivity of intermolecular forces at interfaces. i. determination of the contribution to surface and interfacial tensions of dispersion forces in various liquids1

Role of Surface Active Agents in Wetting

Ideal two-dimensional solutions. ii. a new isotherm for soluble and “gaseous” monolayers

Surface effects of anisotropic London dispersion forces in n-alkanes

Ideal two-dimensional solutions. iii. penetration of hydrocarbons in monolayers