Student projects

Students with interest in the described research topics are invited to come by and discuss the possibility to conduct their bachelor or master project work within the group.

Many different projects can be formulated on the basis of other ongoing research activities in the group and the specific interest and skills of the student. Some examples of suitable projects are described below.

Bio-inspired molecular adhesives
Recent work has shown that the unusually high fracture energy of many bionanocomposites such as bones or teeth is related to their microstructure, and the abilities of their inorganic–organic constituents to dissipate energy, where formation and sequential breakage of sacrificial bonds are of pivotal importance.

Soft, polymeric molecules that join harder and stiffer organic (e.g. collagen and chitin) and inorganic (e.g. hydroxyapatite in bone and calcium carbonate in nacre) constituents are expected to be responsible for the sequential breakage and detachment when the material is subjected to tensile stresses. At a certain load, a bond within the polymer network will break and the composite will extend with an amount related to the next-shortest bridge.

This process can continue until the last sacrificial bond within the network is reached, and in each step the elasticity in the released hidden length opposes the external force. Indeed, this mechanism may also be responsible for the self-healing properties of many organisms as the fracture energy can be dissipated before the surfaces reach complete detachment and the sacrificial bonds can reform if the external force comes as a shock, which works over a limited time and distance.

In this project we will mimic nature in order to make simple but very strong molecular adhesives. If combined with the benefits of stimuli responsive polymers one can possible produce a system which can switch between being adhesive or non-adhesive as a response to an external stimuli.

Charge regulation of soft interfaces
Most surfaces will in aqueous solution carry an electric charge due to the presence of fore example hydroxyl or amine groups. The surface charge is always compensated by counter ions which are distributed with a concentration which, together with the potential, decays with the distance to the surface.

In this project we will investigate how the surface potential changes with the surface separation by measuring electrostatic double layer forces between charged surfaces carrying macromolecules such as polymers or proteins. The results will be compared with measurements of the zeta-potential (the potential in the so-called “slipping plane”).

For students with an interest in modeling the effect of charge regulation due to association of macromolecules can also be investigated.