Determination of the pore-size distribution in gels

• A method for determination of the accessible volume fraction in gels as function of the molecular weight of the solutes is presented. The pore-size distribution is determined by measuring the rate of diffusion of a mixture of solutes into a gel using gel filtration for separation. The solutes, of various sizes, are detected by refractive index measurements. Two marker molecules (blue dextran and glucose) were used to determine the gel void and the amount of liquid adhering to the surface. The technique is simple and can easily be adapted to other systems of a porous nature (membranes, catalyst pellets etc.). The method is applied to an N-isopropylacrylamide gel. This gel is sensitive to temperature changes. A considerable increase in volume is obtained when the temperature is decreased. This makes it suitable for use as a separation agent in gel extraction. In order to assess the performance of this unit operation the pore size distribution for the N-isopropylacrylamide gel was determined at 10 degrees C, 20 degrees C and 30 degrees C, using mixtures of different dextrans as well as different polyethylene glycols.

Subject headings

TEKNIK OCH TEKNOLOGIER  -- Kemiteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Chemical Engineering (hsv//eng)

Keyword

GEL FILTRATION

IN-DIFFUSION

N-ISOPROPYLACRYLAMIDE GEL

PORE-SIZE

DISTRIBUTION

Publication and Content Type

art (subject category)

ref (subject category)