Abstract: Covers processes for making microporous membranes and molecular filtration membranes from vinylidene fluoride polymers, and the products so produced. A continuous version of the process consists of applying a layer of a solution of a polyvinylidene fluoride polymer to a rigidly supported surface of a backing belt to form a film, then passing the belt through a formation bath, in which the membrane is formed. To form the polymer solution, the polymer is dissolved in a liquid vehicle that will dissolve up to about 25% by weight of the polymer at a temperature of at least 50.degree. C. but that dissolves substantially less of the polymer at about 20.degree. C. (room temperature). The polymer solution is formed at 50.degree. C. or higher, and the formation bath is maintained at about room temperature. The formation bath is a mixture of the liquid vehicle solvent with a second liquid that is miscible with the solvent but that is not itself a solvent for the polymer.

Abstract: Covers a continuous process for making a polymeric membrane having at least 60% or more of its volume taken up by intercommunicating pores of substantially uniform size below about 25 micrometers. Consists of applying a layer of a polymer solution on a rigidly supported backing belt, then passing the belt through a formation bath that includes solvent plus a non-solvent for the polymer that is miscible with its solvent. The bath is recirculated at a substantially constant, preselected composition. The porous structure of the membrane is substantially completely formed in the formation bath. Includes extracting any residual solvent from the porous membrane, then drying the membrane. To produce membrane material of consistent, uniform characteristics and quality, the formation bath is maintained at the preselected composition. Either skinned molecular filtration membranes or microporous membranes may be produced by adjusting process parameters, such as the composition of the formation bath.

Abstract: Apparatus for producing electrophoretic migration in an agarose gel slide which includes a slide mounting block containing a salt which maintains slide temperature during electrophoresis processing.

Abstract: Apparatus for rapidly and conveniently drying an agarose gel slide following electrophoresis is provided which utilizes both vacuum and heated air to remove moisture from the slide.

Abstract: The invention concerns a method for the application of sample liquids to a gel type electrophoretic medium which leaves substantially no application artifact in the final electrophoretic pattern. The method consists of placing a cover sheet, having slits formed therein at the desired sample application locations, on the upper surface of the gel. An excess of sample is placed over each slit and allowed to remain in place for a fixed time period. It is then blotted to remove excess sample material and the cover is removed. Sample materials imbibed into the gel will then be appropriately located and in predetermined amounts depending on the gel porosity and time that the sample is in contact with the gel.