Abstract
The kinetics of the collapse of the coil state into condensed states is studied with vibrated granular chain composed of N metal beads partially immersed in water. The radius of gyration of the chain, R <sub>g</sub> is measured. For short chains (N < 140), disk-like condensed state is formed and R <sub>g</sub> decreases with time such that the function ΔR <sub>g</sub> <sup>2</sup> (≡R <sub>g</sub> <sup>2</sup> - R <sub>g</sub> <sup>2</sup> (∞)) A e <sup>-tτ</sup> , where the relaxation time follows a power-law dependence on the chain length N with an exponent γ 1.9 ± 0.2. For the chains with length N ≥ 300, rod-like clusters are observed during the initial stage of collapse and R <sub>g</sub> <sup>2</sup> R <sub>g</sub> <sup>2</sup> (0) - Bt <sup>γ</sup> , with 0.6 ± 0.1. In the coarsening stage, the exponential dependence of δR <sub>g</sub> <sup>2</sup> on time still holds, however, the relaxation time τ fluctuates and has no simple dependence on N. Furthermore, the time dependence of the averaged radius of gyration of the individual clusters, R <sub>g,cl</sub> can be described by the theory of Lifshitz and Slyozov. A peak in the structure function of long chains is observed in the initial stage of the collapse transition. The collapse transition in the bead chains is a first order phase transition. However, features of the spinodal decomposition are also observed. © 2011 American Institute of Physics.