Research programme
Defect engineering is an established term and approach in hard-matter science, most prominently in the
context of tailoring electronic, mechanical, and optical properties of inorganic semiconductors, and more
recently also in organic molecular materials. In sharp contrast, the potential of defect control in soft
matter, with its inherently rich free energy landscape and structural diversity, has not yet been
comprehensively explored. Whereas strategies to make and functionalize defect-free, well-defined
polymeric and colloidal structures have attracted much attention in the past, attempts to classify, assess,
and control defects in soft matter are scarce (one prominent exception being liquid crystals).
The mission of the proposed collaborative research center (CRC) is to shift this paradigm. For this
purpose, we first aim to understand the influence of defects on the structure, dynamics, and properties
of polymeric, colloidal, and amphiphilic systems. Secondly, we want to develop comprehensive
strategies to control the defect formation and thus, gain control over the defect structure(s),
concentration, and temporal evolution. Based on these insights, we aim to
(1) establish a fundamental understanding of the interplay between defects and the adaptivity and resilience
of dynamic soft matter systems and,
(2) enable the development of functional units for devices, wherein defects will be the actual function givers
e.g., by controlling the transport of matter or charges.
For that purpose, we propose a classification of defects in terms of topological defects, connectivity
defects, and doping defects. The impact of these types of defects in soft matter will be evaluated
systematically in a joint effort of experiment and theory. Experimentally, the investigation of the different
defect types requires not only comprehensive synthetic expertise, but also specialized analytical methods
suitable for different environments as well as multiple length and time scales. At this, we will cover a broad
scope of soft matter manifestations, reaching from flexible polymers, to block copolymers and ampihphiles,
but also colloids and biomolecules such as DNA or proteins. We will consider classical soft matter properties, that is, macroscopic elasticity, viscoelasticity, and microscopic permeability and try to find
fundamental physical principles which describe their dependency on the presence of different forms of
defects. In addition, the impact of defects on specific properties such as the electro-optical activity of
polymer- and colloid-based functional units will be considered. As further step, active supramolecular
materials of synthetic and biological origin will be investigated with respect to the controllable induction and
elimination of defects.
To achieve our overarching goal and enable a defect-controlled materials design, the proposed research
requires close and long-term cooperation between scientists from the disciplines of biology, chemistry,
and physics, who are all localized at one of Germany’s renowned centers of polymer and soft matter
science: Mainz