Andreas Früh

Andreas E. Früh is a PhD student at the University of Parma under the supervision of Professor Enrico Dalcanale. Following a lab technician apprenticeship in the R&D department of Givaudan Schweiz AG in Dübendorf, Switzerland he studied chemistry at the Zurich University of Applied Sciences. After receiving his BSc in 2008, he worked as an team leader in the API production department at Bachem AG in Bubendorf, Switzerland. He received his MSc in Chemistry in 2013 from the University of Southern Denmark in Odense, Denmark for his master’s thesis with the title “Preparation of Tetrakis(tetrathiafulvalene)-calix[4]pyrroles Functionalised with Pyrene Units” in the group of Professor Jan O. Jeppesen

Research

Self-Diagnostic Polymers

Damage due to mechanical stresses is a major problem when working with polymeric materials. One of my current research activities is an attempt to prepare and characterise a self-diagnostic polymer, in which mechanical damages can easily be detected. This could be achieved using a polymer, supramolecularly cross-linked using the interactions between host groups integrated in the polymer chains and guest functions on the crosslinker. Since the interactions between the host and guest groups are weaker than covalent bonds, a mechanical damage would be accompanied by the break of supramolecular interactions. By using a fluorescent guest group, whose fluorescence is quenched upon supramolecular complexation, any damage could easily be detected and mapped by fluorescence appearance.

Supramolecular Polymer Blending

The use of supramolecular interactions to convert immiscible polymer blends into miscible ones with uniform properties has been successfully demonstrated on polystyrene and poly(butyl methacrylate) functionalised with phosphonate cavitand hosts and methylated pyridine guests, respectively. Films on gold, containing as low as 2.5 % of host and guest groups, show uniform appearance and behaviour while, non-functionalised blends are clearly separated.

 

Electrochemical experiments showed that the methyl pyridinium guest can, in the polymeric film, be converted into the corresponding radical in the polymer blend. This removes the interactions between the host and guest and leads to a decompatibilisation and separation of the polymer (Figure 1), once heated above the T_g, to impart conformational mobility to the polymer chains.