Polymers and Complex Matter

Abstract

This special issue, in honour of Lothar Schäfer on the occasion ofhis 60th birthday, focuses on polymers and complex matter and coversa broad range of topics both in terms of subject matter and methodsapplied. This reflects the wide and open minded interests of the honoree.Lothar Schäfer began his career in Heidelberg working on theoreticalnuclear physics with H A Weidenmüller. Following a stay at the CEN Saclay in 1974, he turned to the fieldof critical phenomena. He made fundamental contributions to the subject ofdisordered systems, in particular on Goldstone modes with F J Wegner and on Anderson localization with A U Pruisken. With T A Witten heformulated a truly field theoretic description of general polymer solutions.Polymers in solution and the renormalization group approach to their experimentally accessible properties have, since 1980 in Hannoverand 1983 in Essen, been his primary field of research summarized inhis book Excluded Volume Effects in Polymer Solutions as Explained bythe Renormalization Group covering `all you ought to know' on the subject. This work is complemented by analytical studies of polymer dynamics.The subjects contained in this special issue encompass soft matter and its rheology,polymers in confinement and their role in short- and long-range colloidal interactions: discussinglenses, dumbbells, rods and dendrimers.Special topics are short chains, directed molecules and gas permeationthrough polymers.Applications of polymer theory to biological systems include the interactions between DNA molecules and between DNA and proteins and the polymerization of the actin skeleton.Work on random matrix theory, functional renormalization and ageing is devoted to the implications of disorder. Finally, more general aspects of the field theory of polymers and complex matter are discussed, like the Hubbard–Stratonovich transformation,renormalization of polymer field theory, exact renormalizationgroup equations, percolation and growth models, and the subtle matter of Lifshitz-point behaviour, which may appear in copolymeric systems.In January 2005 a workshop `Polymers and Complex Matter' was held in Essen where many of the contributions to this issue were presented and discussed.Many of the authors of this anniversary issue have enjoyed discussions and collaborations with Lothar Schäfer; who always seeks contact with thoseusing different methods in their research. In discussions, hisopen and thorough way of pursuing a subject is always fascinating and makes one share his enthusiasm to find and follow the ideal path to verity anew. The authors wish Lothar Schäfer many more years of continuation in this spirit.