摘要:

Oxide/solution interface is with the clear origin of the surface charge, obtained through ionization of surface hydroxyl groups. The oxide particles produced by flame hydrolysis present fractal aggregates built from nearly spherical particles with constant diameter (AI2O3, SiO2). In the process of acid hydrolysis particles with well defined form (spheres, rods, ellipsoids) and high monodispersity could be obtained (α-Fe2O3, α-β-FeOOH). Different types of oxides are investigated by the means of electric light scattering. An information on the electric surface properties of oxide/solution interface as well as in presence of various additives, particles dimensions and fractal structure is obtained. The process of slow coagulation in presence of bivalent electrolyte and surface active substance is studied electrooptically. The change of dynamic electric behaviour (induced dipole moment) in the processes of interaction is followed. Some considerations are made on the nonequillbium electric properties of the interface and the connection with suspension stability.

ISSN:0193-2691    

DOI:10.1080/01932699708943769

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Foam films from aqueous solutions of an ABA triblock copolymer of polyethylene oxide and polypropylene oxide (M   =   14,000) are studied. A narrow polymer concentration range located below the CMC is investigated at both low and high electrolyte (NaCI) concentrations. The dependence of the surface force on film thickness is monitored by two complementary techniques: the porous plate method and the dynamic method of Scheludko and Exerowa. When the film thickness decreases, the total surface force is initially negative and after a minimum gradually increases to positive values. A transition from electrostatic to polymeric stabilization is induced by increasing the NaCI concentration. Our data can be fitted reasonably well with a combination of the DLVO theory ( van der Waals attraction and double layer repulsion) and de Gennes' scaling theory of steric interaction between grafted polymer layers.

ISSN:0193-2691    

DOI:10.1080/01932699708943770

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The effect of thickness non-homogeneity on the drainage of microscopic horizontal foam films was studied experimentally and theoretically. Quasi-static and asymmetrical distribution of thickness irregularities over the film surface was established in the experiment. This type of dimpling was modelled theoretically and employed to derive a new equation for the film thinning. It differs from the theoretical expressions known from the literature and is in better agreement with the experimentally determined functional dependence of thinning rate on film size.

ISSN:0193-2691    

DOI:10.1080/01932699708943771

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The gas permeability coefficients K (cm/s) of Newton black foam films stabilized by four alkyltrimefhylammonium chloride homologues have been measured. The experimental results demonstrate well pronounced dependence: K decreases with increasing surfactant alkyl chain length. The temperature dependence of K has been studied as well. The experimental data are discussed on the basis of the nucleation theory of fluctuation formation of holes in the foam bilayers, assuming that the gas permeation occurs both through holes and through hole-free part of the film (background permeability). The mechanism of permeation through the hole-free film is discussed using the theories of monolayer permeability. The results are in favour of the energy-barrier theory.

ISSN:0193-2691    

DOI:10.1080/01932699708943772

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The present paper describes a new way of presentation of the classical theory of capillarity. An approach based on the Ω-potential thermodynamic formalism is used. An explicit definition of the Gibbs excess quantities of the extensive thermodynamic functions is proposed. It is emphasized that the Ω-potential is the only extensive thermodynamic function which, when defined as an excess quantity, is not in fact such a quantity. It holds for the case of two-phase plane-interface equilibrium systems. The work of transformation of a homogeneous system into a heterogeneous one at given conditions, (ΔΩ)T,V,μ, is defined by means of Eq.(39). Different capillary systems and different thermodynamic models for their description can be unified on the basis of Eq.(39).

ISSN:0193-2691    

DOI:10.1080/01932699708943773

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

ISSN:0193-2691    

DOI:10.1080/01932699708943774

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor