Toward a 3D physical model of diffusive polymer chains

Recent studies in polymer physics have created macro-scale analogs to solute microscopic chains like DNA by inducing diffusive motion on a chain of beads. These bead persistence lengths O(10) links and undergo under random fluctuations vibration. We present model within new stochastic forcing system: an air fluidizing bed granular media. A spherical 6 mm resin beads crimped onto silk thread are buffeted randomly the multiphase flow grains low density rising “bubbles”. “thermalize” various at different airflow rates, while X-ray imaging captures projection chains’ dynamics With modern 3D printing techniques, we can better represent complex polymers geometrically varying connections their relative strength, e.g., mimicking variable stiffness between adjacent nucleotide pairs DNA. also develop Discrete Element Method (DEM) simulations study chain, where is represented simulated particles connected linear angular spring-like bonds. In experiment, find that velocity distributions follow exponential rather than Gaussian expected from solution. Through use DEM simulation, this difference likely be attributed forces imparted fluidized environment. anticipate expanding future explore wide range composition confinement geometry, which will provide insights into large biopolymers.