Stretching helical nano-springs at finite temperatureH. Wada and R. R. Netz
Physics Department, Technical University Munich - 85748 Garching, Germany
received 5 December 2006; accepted in final form 25 January 2007; published March 2007
published online 27 February 2007
Using dynamic simulations and analytic methods, we study the elastic response of a helical filament subject to uniaxial tension over a wide range of bend and twist persistence length. A low-pitch helix at low temperatures exhibits a stretching instability and the force-extension curve consists of a sequence of spikes. At elevated temperature (i.e. small persistence lengths) the helix melts and a pronounced force plateau is obtained in the fixed-extension ensemble. The torque boundary condition significantly affects the resulting elastic properties.
87.15.-v - Biomolecules: structure and physical properties.
62.25.+g - Mechanical properties of nanoscale materials.
82.37.Gk - STM and AFM manipulations of a single molecule.
© Europhysics Letters Association 2007