Osmomat 090 Membrane osmometer

The measurement is highly dependent on the membrane that is used. Gonotec offers membranes with different "cutoffs" that are made of different materials, so that a suitable configuration can be offered for most applications.

This cell unit must be operated by a Gonotec Control Unit SA or Control Unit B.

Advantages

• high-performance measuring cell
• short response times
• small sample volumes
• highest measuring resolution of 0.1 mm liquid column per digit
• avoids "balloon effects"
• membrane diameter of 40mm

Key data

Smallest detectable pressure

0.1 mm solvent column

Molecular weight range

5,000 to 2,000,000 Dalton, lower range depending on the semi-permeable membrane

Measurement cell volume

approximately 0.5 mL

Membrane diameter

40 mm

Solvents

various organic solvents, water and aqueous electrolyte solvents

Sample vol. of polymer sol.

minimum 3 solutions of 2 mL each (with stepped concentration in the range of 1 to 5%)

Measurement: Membrane osmometer

A membrane osmometer consists of an osmotic cell which is located in a cell thermostat. The osmotic cell is divided into two sections by a semipermeable membrane.

In the lower section, a hermetically sealed cell which is filled with pure solvent, a precision pressure measuring system is installed. The upper section, which is positioned above the semipermeable membrane, is designed as a meander-shaped channel system with a large surface. A funnel tube and a discharge valve enable rinsing and filling of the cell with solvent or polymer solution.

Due to the osmotic pressure difference between solvent and solution, a vacuum, which is related to the concentration of the osmotic actively solute particles, is generated in the lower cell half.