The structures of thin layer formed by microphase separation of grafted Y-shaped block copolymers in solutions

Abstract

We study the structure formation of grafted Y-shaped block copolymers in solutions via dissipative particle dynamics simulations. We systematically examine how the solvent quality, the grafting density, and the incompatibility between polymer blocks affect the morphology of the grafted layer. The layer thickness and the lateral domain size and inhomogeneity of the layer structures are analyzed. A power law, hlayer ~ σ(n), is found between the layer thickness (hlayer) and the grafting density (σ), which shows three regimes, i.e., the brushes regime, the crossover regime, and the mushrooms regime. In the brushes regime, we also find that the exponent n is dependent on the grafting densities and solvent conditions, regardless of the incompatibility between the polymer blocks. In the mushrooms and the crossover regime, a variety of surface structures can be observed, such as mixed micelles, internally segregated micelles, hamburger micelles, segmented wormlike micelles, and dumbbell micelles. The stripe-like structure formed in the brushes regime is investigated in detail. The simulation results are in good agreement with theoretical predictions and experimental observations, and can be helpful for the surface structure design of functional materials.

Influence of Grafting Point Distribution on the Surface Structures of Y-Shaped Polymer Brushes in Solution

“…The simulated annealing technique was used in the simulations. , The “single-site bond fluctuation” model of polymers was applied. , Details of the model system and simulation procedure are given elsewhere. ,, Only a brief account is given here.…”

“…We also found that the morphologies of the grafted polymers are affected by the solvent quality and selectivity, grafting density, as well as the incompatibility between different polymers. More recently, the structures of thin layer formed by grafted Y-shaped block copolymers in different solutions, such as polymer layer thickness and domain size, have been investigated in detail by Gao et al 16 using dissipative particle dynamics. Different with our simulation results, they found that all of the surface structures are irregular and lack long-range order, even though the grafting points are fixed and with uniform distribution.…”

Binary hairy nanoparticles: Recent progress in theory and simulations

“…The studies about end‐grafted diblock copolymer brushes were carried out almost simultaneously with mixed homopolymer brushes. Theory and simulations on this important type of binary polymer brushes have been extensively reported in past two decades . Similar to mixed homopolymer brushes, diblock copolymer brushes with enough incompatibility between the two blocks also experience microphase separation.…”

“…In addition, the same scaling law in poor solvent becomes H 1 = d∝N 1/2 ( τ 3 / χ ) 1/6 ( τ is a parameter which indicates the solvent quality). Lately, the nanostructures of grafted Y‐shaped copolymers were investigated via MC simulations using simulated annealing technique and DPD simulations . Both of these simulations systematically examined how the solvent quality, the grafting density, and the incompatibility between the polymer blocks affect the morphology of the grafted layer.…”

Phase Behavior of Ternary Polymer Brushes

“…Patterned surfaces created by block copolymers have been thoroughly studied for use in biological, electronic, and membrane applications. − As useful as block copolymers are, they have several significant drawbacks. First, the coatings are generally spin coated, meaning that only planar surfaces can be used.…”