Video Transcript: Gelation with Rheo-microscopy
Hey guys welcome back to the lab where today we are looking at gelation through Rheo-microscopy. Rheo-microscopy, as its name might suggest, is a combination of rheology and microscopy and the gelation we’re talking about here is the process of a liquid becoming more elastic as the molecules within start interacting with each other. The gelling agent we have is a hydroxyethyl cellulose. This is commonly found in things like eye drops, bathroom cleaners, and it’s even found in ferret shampoo.
By performing an oscillation temperature sweep, where the sample is wobbled back and forth as temperature rises, we can see the powder dissolving in water simultaneously to the rheological data. Looking at the complex modulus of our sample as the hydroxyethyl cellulose dissolves the plot shows fairly noisy data at the start. This is just where we’re oscillating both powder and water. After 450 seconds, we see the complex modulus increase as the cellulose dissolves, indicating gelling.
What we’re really interested in in is this plateau; this demonstrates that the sample has gelled. This is reinforced in what we see under the microscope, the powder completely dissolves into the water leaving a gel. So why is it important to be able to measure gelling? Well from things like manufacturing consistency, product formulation, and even competitor benchmarking, rheo-microscopy gives you the rheological data and visuals at the same time.
If you’ve got any questions about rheo-microscopy, gelation, or you want to have a chat about anything rheology related, don’t hesitate to get in touch