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