Influence of excluded volume interactions on the dynamics of dendrimer and star polymers in layered random flow

Abstract

The influence of excluded volume interactions (EVIs) governs the dynamics of branched polymeric structures. Therefore, we developed a theory with the inclusion of ubiquitous EVIs on average square displacement (ASD) of the centre of mass in layered random flow (LRF). The mean-field approach is used to account for effective EVIs between non-bonded monomers of generalised Gaussian structures. The effect of polymer topology is analysed under the influence of $$\delta $$ - and power-law correlated LRF. Qualitatively, the theory predicts two anomalous power-law regimes: (i) the intermediate time subdiffusive behaviour with enhanced ASD, due to EVIs, shows the internal motion of the chain and (ii) the long-time superdiffusive behaviour with slightly suppressed ASD represents the overall diffusion of the polymer. The time dependence of ASD in the presence of EVIs reveals the anomalous long-time dynamics governed by a power-law, $$t^{2-\alpha /2}$$ . The model with EVIs predicts enhanced swelling of the polymeric structure and the stretching regime in the magnitude of the ASD. The influence of EVIs in star polymer causes enhanced delay in cross-over time which is further increased with increase in functionality. Dendrimer structure with EVI delays the cross-over time with spacer length. Finally, the increase in EVIs in all topologies causes the enhancement in ASD and delay in cross-over time from subdiffusive to superdiffusive regime.