The KSV NIMA Interfacial Shear Rheometer (ISR) is an advanced characterization instrument for studying the viscoelasticity of Langmuir films.
Features & Benefits
Simultaneous measurement and control of surface pressure due to easy integration with KSV NIMA Langmuir Troughs. This makes it possible to correlate rheological data with monolayer surface pressure and phase transitions that are crucial when working with insoluble surfactants.
Extremely high sensitivity — ISR can measure very weak elastic and viscous moduli of surfaces and interfaces. The high sensitivity of the method is due to the fact that the low inertia hydrophobic probe is moved by a magnetic field without mechanical connections.
In many applications, such as with biofilms, the long-lasting chemical interactions and film creation kinetics need to be followed in real-time. KSV NIMA ISR does not demand any adjustments to compensate for the influence of evaporation as it is based on a unique floating needle technique.
Possibility to work with low volumes down to 4.7 mL saves time and cost when working with valuable compounds and subphases.
The KSV NIMA ISR method is based on interfacial shear rheology. A magnetized probe positioned at the interface is used to create shear deformation on the interface for which response can be measured by optically recording the probe movement.
For more information about the technology, see: Interfacial Shear Rheometry
KSV NIMA ISR enables both dynamic and static measurements to define the viscoelasticity of the interfacial layers. With dynamic measurement, viscoelastic properties are measured as a function of frequency, time, strain, temperature or surface pressure. Static measurement enables creep testing to be performed and indicates whether the system behaves like an ideal Newtonian liquid (dashpot model) or ideal elastic (spring model). These measurements enable the following parameters to be defined:
- Elastic (storage) modulus, G’
- Viscous (loss) modulus, G’’
- Dynamic interfacial viscosity, μs*
- Surface/interfacial viscosity, η
- Relaxation times, τ
The KSV NIMA ISR can be equipped with either a KSV NIMA Langmuir Trough (or Liquid-Liquid Trough) for simultaneous control of the film packing density or a Low Volume Measurement cell to work with small interfacial areas and reduced subphase volumes.
Both systems enable surface pressure measurement thanks to the integrated highly sensitive Wilhelmy balance. The Langmuir Trough and the Low Volume Measurement Cell are divided into an upper and lower compartment, which can be used to study film viscoelasticity at the liquid-air or liquid-liquid interface.
All the ISR systems have hardware solutions designed for easy injection of the chemicals to enable real-time chemical interactions studies. For example, the low volume cell has two injection ports at each end of the cell to enable easy injection of materials (e.g. proteins, enzymes) in the subphase and to allow gradual subphase exchange while measuring.
KSV NIMA Interfacial Shear Rheometer Specification
|Dynamic moduli resolution (mN/m)||0.001|
|Frequency range (rad/s, Hz)||0.01-10, 0.0016-1.6|
|ISR with Langmuir Trough (L×W×H, cm)||90.8×37.0×70.0|
|ISR with Low Volume Cell (L×W×H, cm)||19.0×37.0×70.0|
|Low Volume Measurement Cell (Inner Dimensions)|
|Lower compartment (heavy phase) (L×W×H, cm)||12.0×1.1×0.65 (volume 4.7 mL)|
|Upper compartment (light phase) (L×W×H, cm)||12.0×1.96×0.6 (volume 13.9 mL)|
|ISR with Langmuir Trough (kg)||35|
|ISR with Low Volume Cell (kg)||25|
|Minimum system requirements||
|Operating system requirements||