Home > Research > Out of Equilibrium: Morphology, Mechanics and Dynamics

JPEGThe quantitative determination of reaction or association rate coefficients is a major issue in the field of chemical physics. In a certain number of cases, these rates depend on the time it takes for the reactive species to occupy a specific mutual spatial and orientational configuration that enables subsequent association or reaction step. Such rates are known to be limited by diffusion. Biochemistry offers numerous examples of multi-molecular association (formation of large long-lived complexes) where the mutual diffusion movement of the intervening species is expected to be a key factor controlling the association dynamics.

Moreover, the assumption of viscous hydrodynamics is reasonable for large molecules. The relative simplicity of the association kinetics in homogeneous solutions is lost when one of the reactive species is immobilized near a surface, and deriving the correct association rate in this situation is a challenging issue, even though the volume kon kinetic coefficient is known.

Articles in this section

  • Microtubule organization

    Figure 8. An initially homogeneous and isotropic solution of microtubules might grow into an oriented state if growth of a given filament requires not finding other filaments on its path as it grows.
    We study [1] a microtubule growth model where the increase in size of the plus-end is (...)

  • Colloidal propellers

    Figure 1. The simplest propeller made from an assembly of colloidal spheres. We have shown how the propelling efficiency, i.e the efficiency of transformation of rotation into translation depends on the geometrical characteristics of the aggregate.
    We studied the design principles of the (...)

  • Pebble shapes

    Expertise in dealing with the characterization of shapes by means of curvature, as required for the thermal analysis of membrane shape fluctuation, has lead us to collaborate with Philippe Duringer from the Geology Department of Strasbourg and with Douglas Durian from U-Penn in Philadelphia on (...)

  • Compression modulus of a macroscopic fiber bundles

    We study dense, disordered stacks of elastic macroscopic fibers. These stacks often exhibit non-linear elasticity, due to the coupling between the applied stress and the internal distribution of fiber contacts. We propose a theoretical model for the compression modulus of such systems, and (...)

  • Mestastability of a circular o-ring

    An o-ring takes spontaneously the shape of a chair when strong enough torsion is applied in its tangent plane. This state is metastable, since work has to be done on the o-ring to return to the circular shape. We show that this metastable state exists in a Hamiltonian where curvature and (...)

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