Polymer films are often prepared from water-borne polymer dispersions. The film formation process starting from polymer dispersions encompasses three steps, which are water evaporation, particle deformation, and polymer interdiffusion.  Polymer interdiffusion is important for cohesion of the final film. During interdiffusion, particle boundaries disappear, while polymer chains from adjacent particles mix and form entanglements.

The group employs Förster resonance energy transfer (FRET), a fluorescence technique, to track interdiffusion.  Currently, we work together with BASF SE, investigating the interdiffusion in water-borne pressure-sensitive adhesives (PSAs).  PSAs consist of soft, slightly cross-linked chains.  In the materials currently under study, ionic cross-links are formed during interdiffusion.  Since ionic cross-links can be reversible, they allow for self-healing. Making use of FRET, it was proven that polymer interdiffusion indeed takes place in these materials. Cross-linking was confirmed by mechanical testing.


Persons:
Christopher Hirth,
apl. Prof. Jörg Adams,
Prof. Diethelm Johannsmann

Selected Publications: