Colloid Chemistry and Surface Chemistry(胶体化学和表面化学)专业英语.

repelling. If the solvent is water, the terms hydrophilic and hydrophobic, respectively, are used instead. Lyophobic
colloids include the metal sols. Lyophilic colloids generally have some chemical similarity to the solvent, such as –OH groups able to form hydrogen bonds.
▪ Surface active agent, surfactant (表面活性剂)
▪ Anionic surfactant
▪ Cationic surfactant ▪ Micelle (胶束) ▪ Surface film ▪ Monomolecular film
▪ Detergent (洗涤剂) ▪ Electrophoresis (电泳) ▪ Electroosmosis (电渗) ▪ Isoelectric point (等电点) ▪ Sol (溶胶) ▪ Aerosol (气溶胶) ▪ Gel (凝胶) ▪ Agar gel (琼脂糖凝胶)
Surfactant molecules or ions can cluster together as micelles, which are colloid-sized clusters of molecules, for their hydrophobic tails tend to congregate, and their hydrophilic heads provide protection. Micelles form only above the critical micelle concentration (CMC) and above the Krafft temperature.
Definition:
A colloid, or disperse phase, is a dispersion of one material in another.
Classification:
A sol is a dispersion of a solid in a liquid or of a solid in a solid.
Two regions of charge must be distinguished.
• First, there is a fairly immobile layer of ions that adhere tightly to the surface of the colloidal particle, and which may include water molecules. The radius of shear is the major factor determining the mobility of the particles. The electric potential at the radius of shear relative to its value in the distant, bulk medium is called the zeta potential, ζ, c potential electrokinetic potential.
▪ Emulsion (乳化) ▪ Water in oil emulsion ▪ Oil in water emulsion ▪ Emulsifying agent, emulsifier (乳化剂) ▪ Emulsifying efficiency ▪ Emulsion breaking (破乳) ▪ Emulsion breaker, demulsifier(破乳剂) ▪ Adsorption (吸附) ▪ Adsorption center (吸附中心) ▪ Adsorption equilibrium ▪ Co-adsorption ▪ Selective adsorption ▪ Adsorption layer ▪ Monomolecular adsorption ▪ Multimolecular adsorption
Colloid Chemistry and Surface Chemistry
(胶体化学和表面化学)
4. Colloid Chemistry and Surface Chemistry
(胶体化学和表面化学)
▪ Disperse system (分散体系) ▪ Disperse phase ▪ Disperse medium ▪ Colloid (胶体) ▪ Colloidal state ▪ Colloidal solution ▪ Aggregation (凝聚) ▪ Dialysis (透析) ▪ Sedimentation (沉降) ▪ Sedimentation boundary ▪ Sedimentation velocity
Second, the charged unit attracts an oppositely charged atmosphere of mobile ions. The inner shell of charge and the outer ionic atmosphere of mobile ions. The inner shell of charge and the outer ionic atmosphere is called the electrical double layer.
The hydrocarbon interior of a micelle is like a droplet of oil. NMR shows that the hydrocarbon tails are mobile, but slightly more restricted than in the bulk.
▪ Diffusion (扩散) ▪ Diffusion coefficient ▪ Light scattering ▪ Electron microscope ▪ Surface (表面) ▪ Curved surface (曲面) ▪ Surface tension (表面张力) ▪ Surface energy ▪ Surface pressure ▪ Interface (界面) ▪ Interfacial tension
• Anuid in a gas or a solid in a gas.
• An emulsion is a dispersion of a liquid in a liquid.
A further classification of colloids is as lyophilic (亲液的), or solvent-attracting, and lyophobic (疏液的),solvent-
A gel is a semirigid (半固的，半硬的) mass of a lyophilic sol in which all the dispersion medium has penetrated into the sol particle.
Micelle formation and the hydrophobic interaction
The electrical double layer
A major source of kinetic stability of colloids is the existence of an electric charge on the surfaces of the particles. On account of this charge, ions of opposite charge tend to cluster nearby, and an ionic atmosphere is formed.
Application: micelles are important in industry and biology on account of their hydrocarbon interiors. For this reason, micellar systems are used as detergents and drug carriers, and for organic synthesis, froth flotation, and petroleum recovery.