Thesis subject
MSc - Self-Assembled Gecko-inspired Adhesives
The toes of a gecko have millions of micron-sized hairs packed closely together and each hair branches into hundreds of nanosized spatula shaped structures. The adhesion is based on a combination of weak attractive forces, Van der Waals forces, and capillary forces, that hold the spatulas to the surface a gecko tries to climb. These are physical phenomena and are therefore not strongly dependent on the chemical nature of the materials in contact.
Obviously, a strong and reusable adhesive can be very useful in microelectronics, robotics, biomedical or every-day products such as fixation tapes or sports articles. At present, commercial production of gecko-inspired adhesives is limited by the complexity of the problem and high cost of patterning methods.
Inspired by the excellent adhesive performance of a gecko in this project we will develop nanofabrication processes based on self-assembly. This will allow the fabrication of polymeric nanosized fibrillar arrays with complex 3D structures, hard to achieve with top-down methods. The fabrication of inverse colloidal crystals will result in hour-glass shaped pillars. This particular fibril size and shape is expected to result in significantly enhanced adhesion, because stress concentrations will be decreased at the pillar edges, thereby increasing the toughness of the system.
Experimental Techniques:
The research focuses on:
- Fabrication of colloidal templates using spherical particles.
- Structure formation using moulding and microtoming.
- Adhesion testing with Atomic Force Microscope (AFM).