Research

The research in INTERACT spans from fundamental soft matter physics and chemistry questions to highly applied problems. Among the fundamental questions addressed in the project, what intrigues us most are, for instance:

• topological defects in liquid crystals and how their nature and number depend on surface curvature and symmetry breaking,
• the interaction of light with curved samples of cholesteric liquid crystal, exhibiting a helical modulation of the local symmetry axis that gives rise to a polarization sensitive photonic crystal response,
• the liquid crystalline self-assembly of small molecules or oligomers into macroscopic materials with varying types of long-range order,
• the growth of polymer networks within an ordered liquid crystal medium, and how it can be influenced by confinement and localization of initiation.

The applied research in the project focuses on three parallel tracks:

• Non-electronic wearable technology, based on smart textile core-sheath fibers with liquid crystal incorporated inside the fiber core, making the fibers responsive. Specific applications that we target are textile form factor gas or tensile sensors, which can be integrated in clothing and which function even after long-term storage, since no power source is needed. They can work at room temperature, since liquid crystal mixtures can be tailored to the temperature range of interest.
• Soft, curved actuators for soft robotics, based on liquid crystal elastomer capsules or similar shapes, produced in a microfluidic environment or by electrospinning. The spinning or microfluidic production techniques are amenable to high-throughput production of highly monodisperse spheres or fibers in which the liquid crystal will spontaneously adapt unconventional arrangements, due to the strong confinement. By polymerizing and lightly crosslinking the material, a soft rubber is created that functions like an artificial muscle actuated by reducing or increasing the internal degree of order, for instance by heat or light.
• Unclonable dynamic patterns for secure authentication generated by arrangements of cholesteric liquid crystal spheres which communicate optically with each other, in a way that is unique to each individual sphere arrangement. We are collaborating with computer scientists at the University of Luxembourg Interdisciplinary Center for Security and Trust to convert these optical patterns into digital strings that can be used to securely authenticate objects and persons.