Polymer Swelling Ratio Calculator
Enter dry and swollen mass with polymer and solvent densities to instantly compute the equilibrium swelling ratio Q and polymer volume fraction vr.
Use the Polymer Swelling Ratio Calculator
Swelling Inputs
Mass of the fully dried polymer sample.
Mass after equilibrium swelling in solvent.
Density of the dry polymer (e.g. 1.30 for polyacrylamide).
Density of the swelling solvent (1.00 for water at 25 °C).
Common Density References
| Material | ρ (g/cm³) |
|---|---|
| Water (25 °C) | 1.00 |
| Ethanol (25 °C) | 0.785 |
| Toluene (25 °C) | 0.867 |
| Polyacrylamide | 1.30 |
| Natural rubber | 0.92 |
| PDMS | 1.03 |
| Polyurethane | 1.20 |
| PVA hydrogel | 1.26 |
Enter mass and density values, then click Calculate.
Swelling Ratio
—
Q
Swollen vol / dry vol
Polymer Volume Fraction
—
vr = 1/Q
Polymer fraction in swollen gel
Step-by-step Breakdown
Formulas Used
This volumetric definition is standard in Flory-Rehner swelling theory. All volumes are in cm³ when mass is in grams and density in g/cm³.
Interpretation Guide
| Q Range | Network Description | Typical Systems |
|---|---|---|
| 2 – 5 | Tightly crosslinked | Hard rubber, dense gels |
| 5 – 20 | Moderately crosslinked | Soft contact lenses, elastomers |
| 20 – 100 | Loosely crosslinked | PVA hydrogels, tissue scaffolds |
| > 100 | Very loose / superabsorbent | SAPs, diapers, agricultural gels |
Summary
The Polymer Swelling Ratio Calculator determines the equilibrium swelling ratio (Q) and the polymer volume fraction (vr) for crosslinked polymer networks submerged in a solvent. These two parameters are foundational in characterizing hydrogels, rubber networks, and other swellable materials. By inputting the dry mass, swollen mass, and the densities of both the polymer and the solvent, the tool computes results according to standard Flory-Rehner theory.
How it works
- Enter the dry mass of the polymer sample (before immersion).
- Enter the swollen mass after reaching equilibrium in the solvent.
- Provide the polymer density (g/cm³) — e.g. 1.1 for polyacrylamide.
- Provide the solvent density (g/cm³) — e.g. 1.0 for water at 25 °C.
- Click Calculate to get the swelling ratio Q and polymer volume fraction vr.
- Use the Reset button to clear all fields and start a new calculation.
Use cases
- Characterizing hydrogel crosslink density for biomedical scaffold design.
- Quality control of rubber vulcanizates by solvent swelling tests.
- Evaluating network structure of superabsorbent polymers (SAPs).
- Determining solvent uptake in polymer membrane research.
- Comparing swelling behavior across different crosslinking agent concentrations.
- Supporting Flory-Rehner analysis for crosslink density estimation.
- Teaching polymer physics — concrete illustration of network swelling theory.
- Drug release matrix design where swelling controls payload release rate.