2D Colloidal Monolayers

Similar to how cereals float and cluster on milk, colloidal micro- and nanoparticles naturally arrange into 2D hexagonal patterns when moving on water. In our group, we take advantage of this behavior to create nanoscale patterns with minimal effort. We synthesize both polymeric and inorganic particles, assemble them at the air-water interface, and then transfer the patterns onto solid surfaces. These patterns are used in solar cells or as masks for creating nanowires and plasmonic nanostructures.

 

Shapemorphing Particles

We develop shape-changing nanoparticles whose geometry can be precisely controlled using polarized light. These polymer particles contain light-responsive azo groups that adapt their structure and align under irradiation. As a result, spherical particles can be transformed into anisotropic shapes such as rods. These actively controllable building blocks open up new possibilities for targeted structuring and applications in micro- and nanorobotics.

 

Soft Particles at Interfaces

Soft core-shell particles show fascinating self-assembly behavior. In our group, we design and create these particles with specific molecular structures to control how they come together. When compressed, we observe that the particles shift from a hexagonal pattern to "chain" and "square" arrangements, eventually returning to a hexagonal structure at the highest compression. This unique behavior occurs because the soft outer layers of the particles partially overlap as they are squeezed.

 

 

Stimuli-Responsive Emulsions

Oil and water are naturally immiscible, but they can be combined through emulsions. In our group, we stabilize emulsions with pH- or temperature-sensitive microgel particles. These particles keep the emulsion stable over a long period and can break it down in response to external stimuli. This technique enables precise drug release and offers many possibilities for future applications.

 

 

 

 

Coffee Ring Effect

After spilling coffee, you might notice a ring-shaped stain left by the drying droplet. This is known as the coffee ring effect, and it happens with any suspended particles. However, for applications like coatings and inks, uniform drying is often needed. In our group, we develop methods to achieve this. By coating particles with special polymers, we can make them more stable and ensure they spread evenly as the liquid dries. This technique works with various particle types and sizes and has potential applications in everyday products.

 

Microscopic Geared Mechanism

Advancing nanotechnology requires shrinking mechanical machines, but traditional gears and motors face limitations when miniaturized beyond 0.1 mm. Our research introduces a groundbreaking alternative: microscopic machines powered by light, using optical metasurfaces. This innovative approach allows us to build and control machines at sizes down to just tens of micrometers, with highly precise movements and easy integration into existing chip designs. Our light-driven metamachines open up exciting possibilities for future micro- and nanoscale applications.