- Suitable for the method are polymers or nanoparticles that are soluble or dispersible in aqueous media or organic solvents. The required sample quantity is 100-500 mg. The method covers approximately the molar mass range from 104 to 105.
- GONOTEC OSMOMAT 090 membrane osmometer
- Membranes: cellulose triacetate (cut-off 5000, 10000 and 20000 g/mol), regenerated cellulose (cut-off 20000 g/mol)
- Solvents: water and aqueous salt solutions as well as organic solvents like tetrahydrofuran, toluene, chloroform etc.
- Measurement of the osmotic pressure p as a function of the polymer concentration and extrapolation of the reduced osmotic pressure to the concentration zero
- Numerical average molar mass Mn and 2nd virial coefficient A2,o
- Example: Poly-DADMAC standard materials (see PDF)
Methods of comparison and supplementation
- Aqueous size exclusion chromatography (Mn; MW; D)
- Organic size exclusion chromatography
- Static light scattering (MW; RZ; A2)
- Analytical ultracentrifugation (MZ; D)
- Differential refractometry (dn/dc)
- Dynamic light scattering (dH)
- Vapor pressure osmometry (Mn)