Simulation Of Mixing Charged Brushes Under External Electric Field

With many ends that can be functionalized,star brushes can be used for detecting special matter and surface modification.When the grafting density is high,the star brushes will form a two population structure to occupy more space.If we graft some linear chains with star chains simultaneously,the linear chains will occupy the lower layer and all the ends of star brushes will distribute over the surface so that they can realize maximum functions.On the other hand,there are heterogeneous configurations in the mixing brushes and these configurations can be changed by many factors.As a result,there are many choices to control the configuration of the mixing brushes and these open a routine for design "molecular switch"The two-layer status was studied when the length and charged fraction of the linear chains changed in different external electric field.The external electric field was divided into three cases that without electric field,stretching field and collapsing field,and the phase diagrams were plotted in these three cases.Without electric field,there are three statuses that the linear chains occupy in the lower layer,mix ideally and distribute among the top layer.Under stretching field,the relation of two layers does not change nearly and only the top layer chains are stretched by the electric field.But under collapsing field,a new phase that the linear chains distribute between the star chains generates.Furthermore,if the linear chains are longer,it is more likely to tending to extend for the star brushes and phase transition occurs from the low layer to top layer.When the charged fraction of linear chains increases,the stiffness of linear chains increases so that they are tendency to be stretched.But they also tend to collapse due to the attraction of the plate under the collapsing field,so more complicated phenomenon emergent.Finally,when the linear chains are relative long,as the charged fraction of the linear chains increases,the linear chins transit from the low layer to top layer and then the linear chains split in two inner layers.This transition has not observed in the early studies and is new phenomenon.