In this collection of videos you can learn about manifold phenomena involving colloids, surface tension, polymers, and more. During outreach and teaching activities, I use these self-made slide shows to try to excite young students, high school teachers or laboratory visitors about the field of soft matter and colloid- and interface science.
You can find more videos on our YouTube channel.
In July 2014 me and Lisa Tran performed a science food show in Germany about molecular-cooking. The show was part of a bigger food exhibition in the company Haase-Food, GmbH. Here an impression of it!
Videos of our lab
Lab equipment design with Lego
Our Lego machines are often developed based on undergraduate student involvement. We first design the machines with a 3D drawing software, then we purchase the Lego pieces from an online platform (similar to eBay), last we design computer programs to operate the motors. For instance, at the moment an undergraduate student develops a MATLAB code so that our Lego printer can align bijel fibers in an arbitrary arrangement.
Videos from my research
A mixture of oil, water and a solvent is injected into a channel. Extraction of the solvent causes phase separation in the droplet. The droplet becomes viscoelastic with surface active colloids in the mixture. Then, a continuous thread can be extruded, resulting in continuous liquid fibers with structured surfaces and inner morphologies. The liquid nature of so obtained fibers allows for the transport of molecules and will in the future possibly introduce new approaches for chemical synthesis.
Multiple emulsions by phase separation
Four droplets, composed of different concentrations of oil and water undergo phase separations. The closer the droplet composition to the critical point of the corresponding phase diagram, the more layers are being produced by sequential phase separation events. The individual layers are stabilized by a surfactant. For more info see also my poster or the paper.
Colloids in nature and in the kitchen
River deltas formed by colloids
Did you know that colloidal aggregation shapes landscapes on massive scales? In this short slide show we learn about the basic features of colloids and how these lead to the formation of river deltas.
Cheese and yoghurt as colloids
Cheese and yoghurt have been made for thousands of years. Both originate from milk, yet there is only a small difference in how they are made. Get an impression of how colloidal aggregation can yield different materials on these two classical examples.
Surface tension, water striders and the cheerio effect
The discovery of molecular monolayers
Benjamin Franklin, Lord Rayleigh, Agnes Pockels, Irving Langmuir and Katharine Blodgett: The story starts in 1757 on a ship on troubled waters with the curious natural scientist Franklin and tells how peculiar observations can lead to astonishing insights, how women have contributed to great discoveries and how the size of a molecule can be measured by an surprisingly easy experiment.
The story here was taken from the book "How to Dunk a Doughnut" by Len Fisher.
What is surface tension? What is its origin? How can we measure it? This quick slide show demonstrates the fundamentals of this important concept of physicist and chemists.
Many of us have been mesmerized by the skipping of water striders over the surface of a pond. How is it possible that these insects can use the surface of water like an elastic membrane?
The cheerio effect
Clustering breakfast cereals? When these small cereal rings float on the surface of milk something interesting happens. Upon contact they snap together automatically and form permanent clusters. Learn the origin of this effect in this slide show.
Foams and hydrogels
The mesmerizing colors of soap bubbles
Everybody has seen the mesmerizing colors of soap bubbles. But how can these colors emerge with time? Sir Isaac Newton was the first to realize the origin of these colors. Learn how the interference of light makes the drainage of a soap bubble a pleasure to watch.
Hydrogels in the kitchen
Wobbly jelly, gummy bears and bubble tea are examples of hydrogels. What makes a hydrogel obtain its wobbliness? How can we make a hydrogel? This short slide show will give you the answers.
Particles at interfaces
Many examples of particles at interfaces
You might be surprised but there are many everyday life examples of particles at interfaces. How do the surface properties of such interfacially active particles determine their behavior?
Driving force for surface active particles
Hydrophilic particles gain their interfacial activity by a chemical modification of their surfaces. The origin of the particle attachment however is the high surface tension of the oil-water interface.
Nanocontainer doped anticorrosive coatings
In my PhD thesis I have developed a novel anticorrosive coating with nanoparticles. Learn how such a coating can lead to self healing of damaged barrier coatings on metals.