Collodion type membrane

Also the positive membranes were of the collodion type at which poly-2-vinyl-N-methyl pyridinium chloride or protamine was adsorbed. 

Gottlieb, M. H., Neihof, R., and Sollner, K., 1957, Preparation and properties of strong base type collodion matrix membranes, J. Phys. Chem. 61 154-159. 

Homogeneous liquid membrane electrodes. This type, which is in limited use, is sometimes considered as a solid ion-exchange electrode as the electroactive species, e.g., calcium dioctylphosphate, after being dissolved in an ethanol-diethyl ether solution of collodion, is left to "dry and can function as an ion-selective pellet in an electrode tip. Orion37 use these electrodes with PVC-gelled membranes for Ca2+, K+, BF4 and N03. ... 

Simple osmometers have also been developed by Adair particularly for aqueous colloidal solutions. A thimblc-typc collodion membrane is attached to a capillary tube and contains the solution, When equilibrium is established the difference in level inside and outside the capillary is measured, Capillary corrections are made. For organic solvents a dynamic type osmometer may be used. A membrane of large surface area is clamped between two half cells and attached to each half cell is a fine capillary observation tube. With such an apparatus, equilibrium is rapidly established between solution and solvent contained in the half cells, The volume of the half cell may be small (about 20 cubic centimeters), The level of the solvent is usually aiiangecl to be a little below the equilibrium position, and the height of the solvent in the capillary as a function of time is measured, This procedure is repeated with the level of the solvent just above the equilibrium position. A plot is then made of the half sum of these readings. 

The C-substance is non-toxic in mice, in amounts up to 1 mg., and appears to be a smaller molecule than the type-specific polysaccharide, since it passes through collodion and parchment membranes. ... 

Most ultrafilter membranes are gelatinous, and in the great majority of cases the gel consists of collodion. The other type is the non-gelatinous one. 

The observation that the diffusion rate (save for the exceptional data of Urry) is proportional to the pressure is typical of a very wide class of diffusion membranes of silica, glass, basalt, rubber porcelain, cellulose, collodion, and various polymeric products from styrene, vinyl acetate and similar substances. It may be characteristic of activated diffusion (p. 125) or of various types of flow down tubes (Chap. II). On the other hand, there are... 

Tables 6.1 and 6.2 give examples of potentials developed across various collodion membranes. In Table 6.1, the membranes are doped with different ions. In Table 6.2, different resistances for one type of membrane are compared.

Various permeable membranes were apphed to decrease the rate of electrolyte diffusion under steady state [67], in particular a collodion membrane first proposed in ref. [68] became rather popular. In contrast to ion-selective membranes, no Donnan potential is established when collodion membrane is used. These membranes are introduced to stabilize the system for long-term operation, not to affect UP as is. Many inert viscous substances and porous inert ceramics can serve for the same purpose, and this approach is widely used in modem technologies of miniaturized reference electrodes for applications. Various types of diaphragms (including polymer and ceramics) are used in industrial pH measurements as well [69]. 

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