Oscillating rheometer ISR-1

interfacial sheardigitallaboratory

Overview
The ISR-1 is an interfacial shear rheometer based on the torsion pendulum principle, engineered to quantify shear elasticity and shear viscosity of adsorption and spread layers at liquid/gas and liquid/liquid interfaces. It is optimized for measurements of weak, dilute and soft interfacial films and for long-term studies of structural evolution during extended adsorption times.

Key capabilities

• Interfacial shear rheology: direct measurement of shear elasticity (G') and shear viscosity (η) at liquid interfaces.
• Torsion pendulum measurement principle providing very high sensitivity for soft interfacial layers.
• Compatible with adsorption (Gibbs) layers and spread (Langmuir) monolayers at liquid/gas and liquid/liquid interfaces.
• Interchangeable measuring bodies for free-surface and liquid/liquid interface experiments.
• Temperature-controlled experiments with reproducible conditions from 10 °C to 50 °C.
• Capability for long-term monitoring of interface evolution and time-dependent viscoelastic behavior.
• Optional optical contour analysis for experimental visualization.

Performance highlights

• Minimum detectable shear viscosity: ≈1 μNs/m — resolves extremely weak viscous responses.
• Minimum detectable shear elasticity: ≈1 μPam — detects highly sensitive elastic responses.
• Typical frequency range (torsion-pendulum): 0.02–0.2 Hz.
• Temperature control range for reproducible measurements: 10–50 °C.

Measurement principle
The ISR-1 applies a torsion pendulum: a calibrated measuring body placed at the interface is torsionally excited and the resulting motion is analyzed to extract viscoelastic parameters of weak adsorption and spread layers with high accuracy and sensitivity.

Configuration and accessories

• Standard measuring body for liquid/gas interfaces (sensitive to adsorption layers).
• Bi-conical measuring body for liquid/liquid interfaces and weak films.
• Temperature-controlled jacket or measurement cell for thermal stability.
• Standard laboratory beaker and accessories for common setups.
• USB and RS-232 connectivity for instrument control and data transfer.

Software and analysis

• Real-time acquisition of interfacial shear rheology data.
• Evaluation tools for shear elasticity, shear viscosity and time-dependent viscoelastic analysis.
• Oscillation and torsion-pendulum analysis modes.
• Graphical visualization, comparison of multiple experiments and data export for further scientific processing. Windows-compatible software.

Applications
Suitable for interfacial rheology research including Langmuir monolayers, adsorption (Gibbs) layers, emulsions, foams, protein and biopolymer interfaces and surfactant adsorption studies — supporting fundamental research and industrial formulation development.

Technical specifications

• Shear viscosity range: 1 μNs/m–100 mNs/m
• Shear elasticity range: 1 μPam–100 mPam
• Frequency range: 0.02–0.2 Hz
• Time resolution: approx. 1 minute
• Angular resolution (torsion head): 0.01°
• Position sensor resolution: 0.01°
• Temperature range (controlled experiments): 10–50 °C
• Dimensions (approx.): 500 × 500 × 700 mm
• Weight (approx.): 40 kg
• Power supply: 100–240 VAC, 50–60 Hz
• Power consumption: 110 W