Gel Point Determination
Contact-free & non-destructive rheology
LS Instruments is a pioneer in the field of contact-free rheology using diffusing wave spectroscopy (DWS) and with the DWS RheoLabTM offers an instrument for the development of new and innovative products in the pharmaceutical, food, and personal care industries.
The non-destructive measuring principle coupled with a high measuring throughput makes DWS an indispensable building block in the field of formulation development of viscoelastic products in academic research and the pharmaceutical, food, and cosmetics industries.
Features
Contact-free
Fast
Sealed-sample
Small volumes
As little as 4μL of sample requiredContact-free rheology
Contact-free rheology (also known as microrheology) is a method in which the trajectory of particles in a medium is measured.
With diffusing wave spectroscopy (DWS), LS Instruments offers a unique technology that determines the rheological properties of the medium by measuring changing light patterns behind the sample caused by the Brownian motion of particles in the sample.
In simple terms, particles move more or less freely in the medium depending on the network formed. On this basis, DWS can be used to calculate the mean squared displacement (MSD) as well as storage and loss moduli and viscosity of viscoelastic samples.
Particle Motion in the Sample
Newtonian Liquid
Particles moving freely
Viscoelastic Material
Particles entrapped by network
Benefits of diffusing wave spectroscopy (DWS)
Bulk rheology has emerged as a primary method for assessing the rheological characteristics of samples. However, when observing gelation mechanisms involving the formation of structures by chemical cross-linking or physical network association, it is essential to minimize the external forces acting on the sample to avoid disturbances in structure development.
Additional complexity arises when preformed gels are examined. For example, careful preparation techniques such as the use of templates or precise cutting are required to ensure optimal adhesion to the intended geometry. Subsequently, fine-tuning the application of force, taking into account the surface topography and thickness of the gel, is crucial.
DWS presents a solution to address these challenges:
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With its non-destructive approach, DWS provides an ideal basis for measuring sensitive samples. DWS also offers other interesting advantages:
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With DWS, you not only gain precise insights into your samples but also optimize the efficiency of your experimental workflows.
Figure above: Extract from a gelatine sample characterization at different temperatures. The mean squared displacement (MSD) is an indicator of the degree of freedom of the particles in the system. A straight line indicates full freedom of movement of the particles and therefore a completely viscous system. The more the curve flattens out, the greater the restrictions on the freedom of movement of the particles - a sign of forming networks.
Application: Temperature Dependent Gel-Point Determinationon
Read in this application how DWS is used to measure the gel point temperature.
The measurements were performed on our DWS instrument, the DWS RheoLabTM.
Featured Product
With the DWS RheoLabTM, LS Instruments offers the world's only optical rheometer based on DWS technology.
- Easy measurement setup
- Non-Invasive Measurements
- High Sensitivity to Microstructure Changes
- Wide Range of Measurable Concentrations and Conditions
- Real-Time Monitoring of Gelation Process
- High-frequency