%0 Book Section %1 statphys23_0116 %A Winkler, R.G. %B Abstract Book of the XXIII IUPAP International Conference on Statistical Physics %C Genova, Italy %D 2007 %E Pietronero, Luciano %E Loreto, Vittorio %E Zapperi, Stefano %K distribution dna dynamics flow functions hydrodynamic interactions intermittency non-equilibrium phenomena shear statphys23 topic-7 tumbling under %T Semiflexible Polymers in Shear Flow %U http://st23.statphys23.org/webservices/abstract/preview_pop.php?ID_PAPER=116 %X Experimental studies of individual DNA molecules in steady shear flow by fluorescence microscopy have provided a wealth of information on single polymer dynamics 1,2. In particular, these experiments reveal remarkably large conformational changes due to tumbling motion, i.e., a polymer stretches and recoils in the coarse of time. The dependence of the tumbling time on the shear rate (or Weissenberg number) has been elucidated and orientational distribution functions of $łambda$-DNA have been measured 1,2. A number of theoretical studies have been performed in order to achieve a microscopic understanding of the observed phenomena, which provided various scaling relations for conformational and dynamical properties (3 and references therein). Since shear flows are omnipresent in biological systems and technical applications, e.g., microfluidics, the understanding of the dynamics of semiflexible polymers -- such as DNA -- is of great practical interest. The microscopic conformational properties affect the macroscopic rheological behavior of the polymer solution and, hence, a detailed theoretical description of the microscopic dynamics is desirable. In this contribution, analytical results for the dynamics of a semiflexible polymer in shear flow are presented. An analytical expression is provided for the orientational distribution function and the dependence of the tumbling time on shear rate. It will be shown that these quantities agree almost quantitatively with experimental results. As it turns out, hydrodynamic interactions play a minor role only, as long as the Weissenberg number is used in data presentation. The analytical results show that due to shear flow high order correlations in time and the whole history of time evolution of the system are important for structural as well as dynamical quantities. This is the origin of what is called intermittency phenomena in Ref. 2 -- characterized by algebraic or exponential tails of distribution functions -- although the underlying thermal process is Gaussian and Markovian and the equations of motion are linear. Thus, a polymer in shear flow is an example where a very complex system behavior is obtained despite the underlaying simple Gaussian process. \\ 1) C. M. Schroeder, R. E. Teixeira, E. S. G. Shaqfeh, and S. Chu, Phys. Rev. Lett. 95, 018301 (2005)\\ 2) S. Gerashchenko and V. Steinberg, Phys. Rev. Lett. 96, 038304 (2006) 3 R. G. Winkler, Phys. Rev. Lett. 97, 128301 (2006)

@incollection{statphys23_0116, abstract = {Experimental studies of individual DNA molecules in steady shear flow by fluorescence microscopy have provided a wealth of information on single polymer dynamics [1,2]. In particular, these experiments reveal remarkably large conformational changes due to tumbling motion, i.e., a polymer stretches and recoils in the coarse of time. The dependence of the tumbling time on the shear rate (or Weissenberg number) has been elucidated and orientational distribution functions of $\lambda$-DNA have been measured [1,2]. A number of theoretical studies have been performed in order to achieve a microscopic understanding of the observed phenomena, which provided various scaling relations for conformational and dynamical properties ([3] and references therein). Since shear flows are omnipresent in biological systems and technical applications, e.g., microfluidics, the understanding of the dynamics of semiflexible polymers -- such as DNA -- is of great practical interest. The microscopic conformational properties affect the macroscopic rheological behavior of the polymer solution and, hence, a detailed theoretical description of the microscopic dynamics is desirable. In this contribution, analytical results for the dynamics of a semiflexible polymer in shear flow are presented. An analytical expression is provided for the orientational distribution function and the dependence of the tumbling time on shear rate. It will be shown that these quantities agree almost quantitatively with experimental results. As it turns out, hydrodynamic interactions play a minor role only, as long as the Weissenberg number is used in data presentation. The analytical results show that due to shear flow high order correlations in time and the whole history of time evolution of the system are important for structural as well as dynamical quantities. This is the origin of what is called {\em intermittency phenomena} in Ref. [2] -- characterized by algebraic or exponential tails of distribution functions -- although the underlying thermal process is Gaussian and Markovian and the equations of motion are linear. Thus, a polymer in shear flow is an example where a very complex system behavior is obtained despite the underlaying simple Gaussian process. \\ 1) C. M. Schroeder, R. E. Teixeira, E. S. G. Shaqfeh, and S. Chu, Phys. Rev. Lett. {\bf 95}, 018301 (2005)\\ 2) S. Gerashchenko and V. Steinberg, Phys. Rev. Lett. {\bf 96}, 038304 (2006) [3] R. G. Winkler, Phys. Rev. Lett. {\bf 97}, 128301 (2006)}, added-at = {2007-06-20T10:16:09.000+0200}, address = {Genova, Italy}, author = {Winkler, R.G.}, biburl = {https://www.bibsonomy.org/bibtex/26eb9841a75f17c636f19016437496f19/statphys23}, booktitle = {Abstract Book of the XXIII IUPAP International Conference on Statistical Physics}, editor = {Pietronero, Luciano and Loreto, Vittorio and Zapperi, Stefano}, interhash = {a1e6f4d280ec48f118f50bdb1fdebcdc}, intrahash = {6eb9841a75f17c636f19016437496f19}, keywords = {distribution dna dynamics flow functions hydrodynamic interactions intermittency non-equilibrium phenomena shear statphys23 topic-7 tumbling under}, month = {9-13 July}, timestamp = {2007-06-20T10:16:12.000+0200}, title = {Semiflexible Polymers in Shear Flow}, url = {http://st23.statphys23.org/webservices/abstract/preview_pop.php?ID_PAPER=116}, year = 2007 }