Search results for "Langevin dynamics"
showing 4 items of 14 documents
Stratification of polymer mixtures in drying droplets: Hydrodynamics and diffusion
2020
We study the evaporation-induced stratification of a mixture of short and long polymer chains in a drying droplet using molecular simulations. We systematically investigate the effects of hydrodynamic interactions (HI) on this process by comparing hybrid simulations accounting for HI between polymers through the multiparticle collision dynamics technique with free-draining Langevin dynamics simulations neglecting the same. We find that the dried supraparticle morphologies are homogeneous when HI are included but are stratified in core--shell structures (with the short polymers forming the shell) when HI are neglected. The simulation methodology unambiguously attributes this difference to th…
Conformational studies of the Emp-AKH peptide using Molecular and Langevin Dynamics methods
1998
The secondary structure of the member of the AKH/RPCH family has been studied by Molecular Dynamics and Langevin Dynamics methods. Molecular dynamics simulation were performed in vacuum, model aqueous solution and simulated membrane. Langevin dynamics simulation was performed using the friction factor γ equal to 2 ps-1. Molecular dynamics as well as Langevin Dynamics simulation were conducted at 300 K. All minimum energy conformers have similar backbone structure characterised by the turn consisted out of 3 amino acids, Thr, Pro and Asn7. Structures obtained from Molecular Dynamics simulation are characterised by the lack of hydrogen bonds whereas the structure obtained form Langevin Dynami…
Insight in NLO Polymer Material Behavior from Langevin Dynamic Modeling of Chromophore Poling
2011
Calculation of chromophore polar order, i.e. the polarization of nonlinear optically (NLO) active polymers poled by external field, is challenging. One possible solution is to reproduce the orientation polarization of chromophores under external field using Langevin dynamics (LD) molecular modeling. The present work investigates the influence of chromophore dipole moment, density and field extent on NLO efficiency and polarization/relaxation dynamics. Results of simulations convince us, that the method is applicable for modeling real NLO polymers. In the spotlight of this investigation we would like to describe a NLO polymer as a “ferrofluid” where chromophores are active particles or elect…
Stratification in Drying Polymer–Polymer and Colloid–Polymer Mixtures
2017
Drying polymer-polymer and colloid-polymer mixtures were studied using Langevin dynamics computer simulations. Polymer-polymer mixtures vertically stratified into layers, with the shorter polymers enriched near the drying interface and the longer polymers pushed down toward the substrate. Colloid-polymer mixtures stratified into a polymer-on-top structure when the polymer radius of gyration was comparable to or smaller than the colloid diameter, and a colloid-on-top structure otherwise. We also developed a theoretical model for the drying mixtures based on dynamical density functional theory, which gave excellent quantitative agreement with the simulations for the polymer-polymer mixtures a…