Our research

The 3D-structure, assembly and properties of soft colloids delicately depend on temperature, pressure, concentration, as well as on external forces mediated by flow, tension, electric and magnetic fields. We investigate the assembly of polymers and soft colloids into micellar, membrane, crystalline and quasi-crystalline structures. This is done using scattering methods like SAXS, SANS and Dynamic Light Scattering as well as Molecular Dynamics simulations.

Recent examples in our group are the synthesis and assembly of a colloidal system based on block copolymers that by changing pH can switch between steric and electrostatic interactions [1]. Another example are alternating amphiphilic copolymers synthesized using hydrophobic dicarboxylic acids and hydrophilic poly(ethylene glycol) units exhibit a wide range of self-assembly behaviors and thermal solution properties, which can be systematically varied by adjusting the lengths of the hydrophobic and hydrophilic units. The structures found include single chains, micelles, gels, and highly ordered lyotropic liquid crystals. [2]

Telechelic polymers, which have two chain ends promoting self-assembly into “flowerlike” or interconnected micellar structures, were investigated for their molecular exchange kinetics using time-resolved small-angle neutron scattering. The study revealed that the activation energies of monofunctional and telechelic chain exchange are identical, indicating a multistep process involving a collision-induced single-molecule exchange mechanism, which can be explained by a simple kinetic model.

Quasicrystals are a peculiar state of order differing fundamentally from classical crystalline systems. We study the formation of soft-matter quasicrystals with colloidal systems on length scales from the nano to the micrometer regime. Our goal is a deeper understanding of the ground principles behind their formation and from that being able to produce them in a planned manner. To this end we combine Molecular dynamics simulation [4] with scattering experiments and electron microscopy. 

References:

1: Macromolecules 2024 57 (12), 5818-5830 DOI: 10.1021/acs.macromol.4c00486

2: Macromolecules 2022, 55, 5, 1552–1565

3: Nico König, Lutz Willner, Vitaliy Pipich, Najet Mahmoudi, and Reidar Lund
Phys. Rev. Lett. 124, 197801

4: https://pubs.rsc.org/en/content/articlehtml/2016/sm/c6sm01454b